Evaluating the Cold Tolerance of Stenotaphrum Trin Plants by Integrating Their Performance at Both Fall Dormancy and Spring Green-Up

Abstract

Owing to the poor cold tolerance of Stenotaphrum Trin and the urgent need for shade-tolerant grass species in temperate regions of East China, this study evaluated the cold tolerance of 55 Stenotaphrum accessions, aiming to provide shade-tolerant materials for temperate regions. A fine cold-tolerant turfgrass should have both the advantages of delayed fall dormancy and early spring green-up. However, previous research on the cold resistance of turfgrass has mainly focused on the performance of the spring green-up, with less attention paid to the fall dormancy, which has affected the ornamental and application value of turfgrass. This study first dynamically investigated the leaf colour of each accession during the fall dormancy and the coverage during the spring green-up and evaluated the cold resistance of the accession through membership functions and cluster analysis. Significant differences in the cold resistance were found with the assignment of breeding lines to four categories. The weak correlation (R² = 0.1682) between leaf colour during the fall dormancy and coverage during the spring green-up indicates that using the performance of a single period to represent the cold resistance of accessions is not appropriate. To test whether using the laboratory-based LT50 and stolon regrowth rating analysis can replace the above-improved method, we conducted a related analysis and found that the fit between these two methods is very poor. This phenomenon is attributed to the poor correlation between the laboratory-based parameters and the pot-investigated data. Therefore, this study presents a cold resistance evaluation method for Stenotaphrum that integrates performance in both the fall dormancy and spring green-up periods. This improved evaluation method cannot be simplified by the growth performance of a single period or replaced by using laboratory-based LT50 and stolon regrowth tests. With the help of this improved method, several excellent cold tolerance accessions (ST003, S13, and S12) were identified for temperate regions of East China.

1. Introduction

The tropical turfgrass Stenotaphrum Trin has both feed and ornamental value [1]. Due to its much greater shade tolerance than that of other warm-season turfgrasses, Stenotaphrum species are preferred for use in shaded landscapes in tropical and subtropical regions [2,3]. However, its poor cold tolerance severely restricts its use in temperate regions [4,5,6]. Given the need for shade-tolerant turfgrasses in the temperate regions of East China, the use of Stenotraphrum requires the identification and use of cold-resistant germplasm for acceptance and application by the public.

Unlike annual plants such as wheat that do not undergo the fall dormancy process, perennial turfgrass with strong cold resistance should have both the advantages of delayed fall dormancy and early spring green-up [7,8,9]. Field and laboratory evaluations are commonly used for evaluating cold resistance. Field evaluation is considered as a relatively accurate method of evaluating cold resistance. However, field evaluations mainly focus on the performance of green-up in the following year, with less attention paid to the performance of fall dormancy [10,11]. Electrolyte leakage and tissue regrowth measurements are common laboratory methods used to assess cold tolerance in turfgrass species [5,12,13]. Electrolyte leakage has been shown to poorly represent the actual cold tolerance [14,15,16]. Measurements of tissue regrowth have also been shown to be poorly correlated with cold resistance [4,17,18]. These methods are likely not reflective of actual cold tolerance because they do not account for a plant’s ability to retain colour in the fall or an ability to green-up earlier in the spring. Therefore, the objective of this research was to measure both fall dormancy and spring green-up to assess the cold tolerance of Stenotaphrum breeding lines and to compare this assessment to electrolyte leakage and stolon regrowth following exposure to cold.

Stenotaphrum plants can be divided into seven categories (https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:19069-1#source-KB, accessed on 20 June 2024). (1) Stenotaphrum helferi. the native range of this species is South China to Peninsula Malaysia, Philippines. It is a perennial or rhizomatous geophyte and grows primarily in the wet tropical biome. (2) Stenotaphrum clavigerum. The native range of this species is Aldabra to Assumption. It is an annual and grows primarily in the seasonally dry tropical biome. (3) Stenotaphrum dimidiatum. The native range of this species is coastal Kenya to South Africa, West Indian Ocean, and the Indian Subcontinent to Peninsula Malaysia. It is a perennial or rhizomatous geophyte and grows primarily in the seasonally dry tropical biome. (4) Stenotaphrum micranthum. The native range of this species is Southeast Tanzania to the West Indian Ocean, Spratly Islands, and East Malaysia to the Pacific Ocean. It is an annual and grows primarily in the seasonally dry tropical biome. (5) Stenotaphrum oostachyum. The native range of this species is Northwest and Central Madagascar. It is a perennial or rhizomatous geophyte and grows primarily in the seasonally dry tropical biome. (6) Stenotaphrum secundatum. The native range of this species is Southeast U.S.A. to eastern and southern South America and West Tropical Africa to Chad. It is a perennial or rhizomatous geophyte and grows primarily in the seasonally dry tropical biome. It is used as animal food and a medicine and has uses environmentally and for food. (7) Stenotaphrum unilaterale. The native range of this species is Central Madagascar. It is a perennial or rhizomatous geophyte and grows primarily in the seasonally dry tropical biome. The distribution of Stenotaphrum plants in China is mainly in South China. The use of which is also mainly in the tropical and subtropical regions of China. No dominant variety was found. Significant variations in cold tolerance among the species of Stenotaphrum plants [5,6] have been detected. Although the cold tolerance has been investigated on many accessions from Europe and North America [19,20,21,22], the large-scale cold tolerance evaluation of Stenotaphrum plants from China is still lacking. This notion is further supported by the finding that Stenotaphrum research undertaken by Chinese scholars mainly focuses on molecular maker analysis, physiology, and pathology, with little attention paid to the cold tolerance evaluation of Stenotaphrum plants from China [23,24,25,26,27,28,29,30]. This study used 55 accessions of Stenotaphrum plants, the composition of which was mainly wild accessions from China, aiming to establish a suitable cold tolerance evaluation method for Stenotaphrum plants and identify several accessions that can be applied to the temperate regions of East China.

Specifically, this study first dynamically investigated the leaf colour during the fall dormancy and the coverage during the spring green-up of 55 Stenotaphrum Trin resources and evaluated their cold resistance by integrating the two-index using a membership function. By analysing the correlation between autumn/winter leaf colour and next year’s green-up coverage, as well as comparing the growth performance of a single growth period with the ranking of a comprehensive evaluation, whether this method can be simplified by the growth performance of the fall dormancy or spring green-up is clarified. Furthermore, the cold resistance of these resources was evaluated through the laboratory-based cold resistance evaluation methods (leaf LT50 and stolon regrowth analysis) and was ranked and clustered through membership functions and cluster analysis. Whether field evaluation methods can be replaced by laboratory evaluation methods was determined by comparing the differences between laboratory cold resistance evaluation data and field evaluation data. By conducting a correlation analysis between field evaluation data and laboratory evaluation data, the reasons for the differences between field evaluation and laboratory evaluation were clarified. Through the above series of experiments, this study ultimately presented a method to compensate for the shortcomings of the current evaluation methods for the cold resistance of turfgrass and clarified whether this improved method can be simplified or replaced by other methods.

2. Materials and Methods

2.1. Accession Information

Eighty domestic and foreign accessions of Stenotaphrum were collected for cold tolerance evaluation. These accessions came from China (63), the United States (10), South Africa (3), Zimbabwe (1), Australia (1), Argentina (1), and Vanuatu (1). At one year of planting in Nanjing, China, only 55 accessions had survived, i.e., 25 accessions did not survive the winter. Among the 55 surviving accessions, 41 were sourced from China, 8 from the United States, 2 from South Africa, 1 from Zimbabwe, 1 from Australia, 1 from Argentina, and 1 from Vanuatu (Supplementary Table S1). Specifically in China, the strains were obtained from Fujian Province (14), Hainan Province (14), Yunnan Province (5), Guangxi Province (5), and Guangdong Province (3) and conformed to the distribution characteristics of Stenotaphrum (https://www.iplant.cn/z/frps/33150, accessed on 15 June 2024). Subsequently, the cold resistance of these 55 accessions was evaluated.

2.2. Plant Growth Conditions

The 50 accessions for the potted experiment were planted in flower pots with a bottom diameter of 18 cm. The flower pot was filled with half soil and half sand. Each accession contained three replicates. All the accessions were cultivated in the turfgrass nursery of Nanjing Botanical Garden Mem. Sun Yat-Sen, China. Compound fertilizer was applied once a month [31]. The dosage used was 0.5 g/pot for the pot experiments. The lowest temperature in winter was −10 °C. The detailed climate information is listed in Supplementary Table S2.

2.3. Investigation of Leaf Colour during the Fall Dormancy and Coverage during the Spring Green-Up

From the end of October 2022 to the middle of December 2022, photos of potted accessions were taken during the fall dormancy. The interval at which the images were taken was 7 days. The leaf colour was scored according to the GBT30395-2013 standard as previous reported [32,33,34,35].

From the end of April 2023 to the beginning of June 2023, photos of potted accessions were taken during the green-up. The rate of green-up was obtained through visual inspection [32,33,34,36].

2.4. LT50

The experiment was conducted in September 2023. According to previous methods [37], the lethal temperature killing 50% of the plants (LT50) was determined by the electrolyte leakage method, and each treatment included 4 replicates. Briefly, the leaves of healthy plants were removed and rinsed 3 times with deionized water, after which the water that clung to the leaf surface was removed with filter paper. The leaves were cut to a length of approximately 0.5 cm and divided into 5 parts (2 g each). The samples were treated in a cryogenic circulator (Polyscience Company, Warrington, PA, USA), followed by an overnight pre-culture at 4 °C. The low-temperature gradients were set to 4, −1, −6, −11, and −16 °C. After thawing at 4 °C, the electrolyte was extracted by adding 20 mL of deionized water. The conductivity was measured with a conductivity meter (Shanghai Leici Instrument, Shanghai, China) before and after the samples were boiled in a water bath for 15 min.

$\mathrm{electrolyte}\mathrm{leakage}={\displaystyle \frac{\mathrm{conductivity}\mathrm{before}\mathrm{boiling}\mathrm{water}\mathrm{bath}}{\mathrm{conductivity}\mathrm{after}\mathrm{boiling}\mathrm{water}\mathrm{bath}}}\ast 100\%$

The LT50 was obtained by fitting the logistic growth equation:

$\mathrm{Y}={\displaystyle \frac{\mathrm{YM}\ast \mathrm{Y}0}{\left(\mathrm{YM}-\mathrm{Y}0\right)\ast \exp \left(-\mathrm{k}\ast \mathrm{x}\right)+\mathrm{Y}0}}$

where Y is the electrolyte leakage, x is the temperature, and YM and Y0 are the maximal and initial electrolyte leakage. K is the rate constant. The LT50 is the x value where Y equals 50%.

2.5. Stolon Regrowth Experiments

The experiment was conducted in September 2023. Using the methods in [38], stolon regrowth was evaluated via the number of stolons regenerated after low-temperature treatment. The stolons with 5 nodes were treated with 5 temperature gradients (8, 3, −2, −7, and −12 °C). Each treatment included 3 replicates (10 stolons per replicate). After thawing at 4 °C for 24 h, the stolons were planted in plugs filled with half soil and half sand. After 7 days of cultivation in the laboratory, the number of regrowing stolons was determined.

2.6. Membership Function Analysis

The comprehensive cold tolerance evaluation was carried out using the membership function method [39,40,41]. Briefly, the subordination function value of the average greenness, average coverage, and total relative regrowth rates were calculated by the following equation:

$\mathrm{Uij}={\displaystyle \frac{\mathrm{Xij}-\mathrm{Ximin}}{\mathrm{Ximax}-\mathrm{Ximin}}}$

whereas the subordination function value of the LT50 was calculated by the following equation:

$\mathrm{Uij}=1-{\displaystyle \frac{\mathrm{Xij}-\mathrm{Ximin}}{\mathrm{Ximax}-\mathrm{Ximin}}}$

i: a certain material, j: the index, U: the membership grade, Xij: the measured value of the index in a certain material, Ximin: the minimum value of the index in material i, and Ximax: the maximum value of the index in material i.

2.7. Data Statistics and Graphing

The cluster analysis was performed by using squared Euclidean distance coefficient and linkage between groups cluster method in SPSS 19.0 software. Correlation analysis was conducted using Graphpad Prism 9.5 software. For the tables, the data presented are the means ± standard error of at least three replicates. The differences among accessions in a same column was assessed using SPSS 19.0 software and a significant difference is indicated by different letters.

3. Results

3.1. Investigation of Leaf Greenness during the Fall Dormancy and the Coverage during the Spring Green-Up Using the Pot Experiment

Since only 55 accessions survived a winter among the 80 accessions (Supplementary Table S1), detailed cold tolerance evaluations were conducted on the surviving 55 accessions. The investigation of leaf greenness began at the end of October and lasted until late December. As autumn and winter continued, the leaf greenness of Stenotaphrum gradually decreased and all the accessions progressed to a withered yellow state at the end of the monitoring period (Table 1). To objectively reflect the trend of changes in greenness, we averaged the data from 8 time points and obtained the average greenness. This indicator was subsequently used to rank the greenness of the 55 accessions in autumn and winter. The greater the average greenness was, the longer the green period was during the fall dormancy. The average greenness of these accessions varied greatly, ranging from 4.625 to 1.375. The three accessions with the highest average greenness were ST003, S12, and 674925-1. The three accessions with the lowest average greenness were S01, S27, and S28.

The investigation of coverage began at the end of April and lasted until early June. As the green-up period progressed, the grass gradually turned green, and by the end of monitoring, most accessions had approached a complete green-up state (Table 2). To objectively reflect the trend of this green-up change, we averaged the greening coverage at four-time points and obtained the average coverage. By using this indicator, the average coverage of the 55 accessions during the green-up was ranked. A higher average coverage indicates the faster green-up ability of an accession. The average coverage varied greatly among the accessions, ranging from 85% to 9%. The three accessions with the highest average coverage were 291594, S62, and S13. The three accessions with the lowest average coverage were S02, S10, and S28.

3.2. Membership Function Analysis and Cluster Analysis Based on Pot Experiment Results

The data for the leaf colour during the fall dormancy and the turfgrass coverage during the spring green-up was analysed using membership function analysis. The score obtained was used to rank the cold tolerance. The cold tolerance varied greatly among the accessions, ranging from 0.87 to 0. The three accessions with the highest cold tolerance were ST003, S13, and S12. The three accessions with the lowest cold tolerance were S27, S02, and S28 (Table 3). The picture of these six accessions at fall dormancy and spring green-up was presented in Supplementary Figure S1. Cluster analysis revealed that these accessions were divided into two categories: cold tolerant and cold sensitive (Figure 1). The cold tolerance category can be further subdivided into two subcategories: super cold-tolerance and middle cold-tolerance. The cold sensitive category can be subdivided into two subcategories: super cold-sensitive and middle cold-sensitive (Figure 1). The accessions ranking 1–13 are mainly concentrated in the super cold-tolerant subcategory. The accessions ranking 14–46 are mainly concentrated in middle cold-tolerant subcategory. Those that ranked 47–51 are gathered in the middle cold-sensitive subcategory, and those that ranked 52–55 are gathered in the super cold-sensitive subcategory (Figure 1).

The correlation analysis revealed that a positive correlation existed between autumn/winter leaf greenness and the turfgrass coverage during the spring green-up (Figure 2). Accessions with delayed fall dormancy will have an early spring green-up rate. However, the poor R² (0.1682) indicates a weak correlation, suggesting that it is inappropriate to simplify the cold resistance evaluation by investigating the growth performance of a single period. This result was further confirmed by the discrepancy between the ranking of autumn leaf colour or spring coverage rate and the ranking of comprehensive evaluation (Table 3).

3.3. Laboratory-Based Leaf LT50 and Stolon Regrowth Rate Analysis

To investigate whether the pot evaluation can be replaced by the laboratory-based cold resistance evaluation methods, we conducted leaf LT50 and stolon regrowth rate analysis. The cold tolerance of the leaves was measured through an electrolyte leakage test (Table 4). Logistic equation fitting was performed on the relative conductivity of each accession, and the fitting degree (R²) of each equation was greater than 0.86, indicating that the equation fit was good and that the obtained LT50 was highly reliable. A more negative LT50 value indicates a greater cold tolerance ability for leaves. A significant difference in leaf LT50 was detected among the accessions, ranging from −9.32 to 3.45. The three accessions with the most favourable LT50 values were S39, S005, and 410364. The three accessions with the lowest LT50 values were S11, S006, and S27.

Since the spring green-up of Stenotaphrum depends on the budding of the stolons, the regrowth ability of the stolons was evaluated. For all the accessions, as the temperature during the low-temperature pre-treatment decreased, the ability of the stolons to regrow significantly decreased. At −7 °C, most accessions lost their ability to regrow, while at −12 °C, all accessions lost their ability to regrow (Table 5). Given the significant differences in the ability of the accessions to regrow at relatively normal temperatures (8 °C), the regrowth ability of stolons at 8 °C was used as a control and the regrowth ability of stolons under other temperature treatments was standardized. The total relative regrowth rate of stolons at low temperatures was subsequently obtained by averaging the total relative regrowth rate of stolons at −3 °C, −2 °C, and −7 °C. A higher total relative regrowth rate indicates a greater ability for stolons to regrow in the next year. The total relative regrowth rate varied greatly among the accessions, ranging from 52% to 13%. The top three accessions in terms of total relative regrowth rate were S30, S39, and S25. The three accessions with the lowest total relative regrowth rates were S27, S10, and 300129.

3.4. Membership Function Analysis and Cluster Analysis Based on Laboratory Results

The score and rank based on the laboratory results were obtained by membership function analysis (Table 6). A significant difference between the laboratory-based rank and the pot-evaluated rank was detected, and the coincidence degree between them was poor (Table 3 and Table 6). Cluster analysis revealed that these accessions could be divided into two categories and three subcategories based on the laboratory results (Figure 3). Specifically, the accessions ranking 1–9 are clustered in one subcategory (cold-tolerant). The accessions ranking 10–50 are clustered in one subcategory (middle cold-sensitive), while those rankings 51–55 are clustered in one subcategory (super cold-sensitive) (Figure 3). A very poor consistency with the clustering results between the pot evaluation and the laboratory-based evaluation was found (Figure 1 and Figure 3).

3.5. Correlation Analysis between the Laboratory-Based Data and the Pot Analysis Data

A correlation analysis was conducted between LT50 and other data. It was found that LT50 was not correlated with the average greenness during the autumn/winter nor average coverage during the spring green-up but was correlated with the total relative regrowth rate (Figure 4).

A correlation analysis was conducted between the total relative regrowth rate and other data. It was found that the total relative regrowth rate was not correlated with average greenness but was positively correlated with average coverage during the spring green-up (Figure 5).

4. Discussion

4.1. Establishment of a Method for Evaluating the Cold Tolerance of Stenotaphrum by Integrating Its Performance at Both the Fall Dormancy and the Spring Green-Up

It is assumed that the cold resistance of the leaves of perennial turfgrass is crucial when it first encounters autumn/winter cold, while the regrowth ability of stolons is crucial for rapid spring green-up. Briefly, when plants encounter chilling injury, their leaves strive to maintain photosynthesis by prolonging the green period and synthesizing energy to resist chilling injury. Secondly, the leaves transport photosynthate to the stolon to store energy for spring green-up. Leaves with a strong cold resistance are more conducive to the implementation of the above process. The bud from the stolon was the initial site for spring green-up. Therefore, the cold tolerance of perennial turfgrass relies on both the leaves and stolons. This mechanism is completely different from the mechanism of cold resistance in annual plants, which do not experience fall dormancy and spring green-up [42,43,44]. Moreover, the use of an evaluation system for the cold resistance of annual plants is inappropriate for evaluating the cold resistance of perennials [45,46,47,48]. A successful cold-tolerant perennial grass plant needs to be characterized by both delayed fall dormancy and early spring green-up. In this study, through the dynamic investigation of changes in leaf colour in autumn/winter and green coverage in the following year and the membership function analysis and cluster analysis, the growth performance of 55 Stenotaphrum accessions in these two stages was evaluated (Table 1, Table 2 and Table 3; Figure 1). This improved evaluation method compensates for the limitation of the previous cold tolerance evaluation method, which mainly focused on the spring green-up stage and paid less attention to fall dormancy [10,11]. The cold-tolerant accessions selected by this improved method have more ornamental value and are easier for the public to accept. The results showing that the autumn/winter leaf colour and the spring green-up coverage has a weak correlation and that the rank fit between a single period and these two periods is poor indicates that the growth performance of a single period cannot replace the overall evaluation (Figure 2; Table 3). The use of technical methods can only regulate the growth performance of one period (e.g., fall dormancy) and does not affect the growth performance of another period (e.g., spring green-up), supporting the above results [49,50].

4.2. This Improved Evaluation Method Cannot Be Replaced by Laboratory Evaluation

The laboratory-based cold tolerance results and the pot cold tolerance results are inconsistent (Table 3 and Table 6; Figure 1 and Figure 3). There was no correlation between LT50 and the autumn leaf colour or the spring green-up coverage. The total relative regrowth was not correlated with the autumn/winter leaf colour and only correlated with the next year’s green coverage (Figure 4 and Figure 5). This explains why LT50 and stolon regrowth data cannot fully reflect the cold resistance of Stenotaphrum accessions. The inconsistency of the LT50 or the stolon regrowth data to the cold tolerance found in other perennial grass might be also partially attributed to this reason [16,17].

The stolon regrowth rate is positively correlated with the spring green-up coverage (Figure 5), which is in agreement with reports on other turfgrasses [5,51]. These data can to some extent reflect the situation of spring green-up of turfgrass. However, caution should be taken when using this method for cold tolerance evaluation in the future due to the weak correlation.

4.3. Screening of Several Excellent Cold-Tolerant Accessions That Can Be Directly Used in Temperate Regions of China

Through the comprehensive evaluation method, we selected excellent-cold-resistance accessions, which were represented by ST003, S13, and S12 (Table 3). These excellent accessions were obtained from Sydney, Australia, Wenchang, Hainan (China), and Tengchong, Yunnan (China) (Supplementary Table S1). Although several studies have evaluated the cold resistance of Stenotaphrum plants, most have focused on accessions from Europe and North America [19,20,21,22]. This study evaluated the cold resistance of Stenotaphrum plants mainly using Chinese accessions. Due to cold tolerance being an important factor limiting plant geographical distribution [52] and cold tolerance being evaluated in temperate regions in China, the selected excellent-cold-resistance accessions can be directly applied locally. In the future, we plan to further evaluate the shade tolerance of these cold-tolerant accessions and screen for excellent shade-tolerant grass accessions that can be applied in temperate regions.

5. Conclusions

A turfgrass with good cold resistance should have both the advantage of delayed fall dormancy and early spring green-up. Based on the situation that the previous cold tolerance evaluation of turfgrass mainly focused on the spring green-up and paid less attention to its performance in the fall dormancy, this study integrates the performance of these two stages by dynamically investigating the autumn/winter leaf colour and next year’s coverage and uses membership functions and cluster analysis to comprehensively evaluate the cold resistance of 55 Stenotaphrum accessions. This method cannot be simplified by the performance of one period, nor can it be replaced by indicator measurements conducted in the laboratory. The establishment of this method compensates for the shortcomings of previous methods for evaluating the cold tolerance of turfgrass. With the help of this improved method, we have screened several excellent-cold-tolerance accessions (ST003, S13, and S12) for the temperate regions of East China.

Author Contributions

J.-Q.Z. and Z.-Y.W. designed the work. J.Q. and D.-L.H. carried out the experiments. D.-L.H., J.-Q.Z. and Z.-Y.W. wrote the paper. J.-Y.Z., J.-B.C., D.-J.S. and J.-X.L. revised the paper. All authors contributed to the article. All authors have read and agreed to the published version of the manuscript.

Data Availability Statement

The original contributions presented in the study are included in the article/Supplementary Materials, further inquiries can be directed to the corresponding authors.

Conflicts of Interest

The authors declare no competing interests.

Footnotes

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Figures and Tables

Figure 1. Cluster analysis based on pot experiment results.

Figure 2. Correlation between the average greenness during the fall dormancy and average coverage during the spring green-up. The P and R2 are the fitted parameters. The symbol * indicates a correlation.

Figure 3. Cluster analysis based on laboratory results.

Figure 4. Correlation between LT50 and other parameters. (A) Correlation between LT50 and average greenness. (B) Correlation between LT50 and average coverage. (C) Correlation between LT50 and total relative regrowth rate. The P and R2 are the fitted parameters. The symbol * indicates a correlation.

Figure 5. Correlation between total relative regrowth rate and other parameters. (A) Correlation between total relative regrowth rate and average greenness. (B) Correlation between total relative regrowth rate and average coverage. The P and R2 are the fitted parameters. The symbol * indicates a correlation.

Table 1

Leaf greenness during the fall dormancy.

Name	Leaf Greenness																Av. Greenness
	29 October		5 November		12 November		19 November		26 November		5 December		10 December		17 December
ST003	7.000 ± 0.577	b	7.000 ± 0.577	a	6.000 ± 0.289	a	5.000 ± 0.000	a	4.000 ± 0.289	a	3.000 ± 0.000	a	3.000 ± 0.000	a	2.000 ± 0.577	a	4.625 ± 0.289	a
S12	7.000 ± 0.000	b	7.000 ± 0.000	a	6.000 ± 0.289	a	5.000 ± 0.289	a	4.000 ± 0.000	a	3.000 ± 0.577	a	2.000 ± 0.289	b	1.000 ± 0.000	b	4.375 ± 0.180	ab
674925-1	7.000 ± 0.000	b	7.000 ± 0.000	a	6.000 ± 0.289	a	4.000 ± 0.577	b	3.000 ± 0.000	b	3.000 ± 0.000	a	2.000 ± 0.000	b	1.000 ± 0.000	b	4.125 ± 0.108	bc
674925-3	7.000 ± 0.000	b	7.000 ± 0.000	a	6.000 ± 0.289	a	4.000 ± 0.000	b	3.000 ± 0.000	b	3.000 ± 0.000	a	2.000 ± 0.289	b	1.000 ± 0.000	b	4.125 ± 0.072	bc
410361	8.000 ± 0.577	a	7.000 ± 0.577	a	6.000 ± 0.289	a	4.000 ± 0.000	b	3.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	4.000 ± 0.180	cd
S004	7.000 ± 0.000	b	6.000 ± 0.000	b	5.000 ± 0.000	b	4.000 ± 0.289	b	3.000 ± 0.000	b	3.000 ± 0.000	a	2.000 ± 0.289	b	1.000 ± 0.000	b	3.875 ± 0.072	cde
S04	7.000 ± 0.577	b	6.000 ± 0.000	b	5.000 ± 0.000	b	4.000 ± 0.000	b	3.000 ± 0.000	b	3.000 ± 0.000	a	2.000 ± 0.000	b	1.000 ± 0.000	b	3.875 ± 0.072	cde
S08	6.000 ± 0.000	b	6.000 ± 0.000	b	6.000 ± 0.000	a	4.000 ± 0.577	b	3.000 ± 0.289	b	3.000 ± 0.289	a	2.000 ± 0.289	b	1.000 ± 0.000	b	3.875 ± 0.180	cde
S25	6.000 ± 0.000	b	6.000 ± 0.000	b	6.000 ± 0.000	a	4.000 ± 0.577	b	3.000 ± 0.289	b	3.000 ± 0.289	a	2.000 ± 0.289	b	1.000 ± 0.000	b	3.875 ± 0.180	cde
S39	7.000 ± 0.000	b	6.000 ± 0.000	b	5.000 ± 0.000	b	4.000 ± 0.000	b	3.000 ± 0.289	b	3.000 ± 0.289	a	2.000 ± 0.000	b	1.000 ± 0.000	b	3.875 ± 0.072	cde
S48	7.000 ± 0.000	b	6.000 ± 0.000	b	6.000 ± 0.000	a	4.000 ± 0.577	b	3.000 ± 0.289	b	2.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	b	3.875 ± 0.108	cde
S13	7.000 ± 0.000	b	6.000 ± 0.000	b	5.000 ± 0.000	b	4.000 ± 0.000	b	3.000 ± 0.000	b	2.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	b	3.75 ± 0.000	de
S26	7.000 ± 0.000	b	6.000 ± 0.000	b	5.000 ± 0.000	b	4.000 ± 0.000	b	3.000 ± 0.000	b	2.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	b	3.75 ± 0.000	de
S31	6.000 ± 0.000	b	6.000 ± 0.000	b	5.000 ± 0.000	b	4.000 ± 0.000	b	3.000 ± 0.000	b	3.000 ± 0.000	a	2.000 ± 0.000	b	1.000 ± 0.000	b	3.75 ± 0.000	de
S58	7.000 ± 0.577	b	6.000 ± 0.289	b	5.000 ± 0.000	b	4.000 ± 0.000	b	2.000 ± 0.000	c	2.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	b	3.625 ± 0.108	ef
647924-2	7.000 ± 0.289	b	6.000 ± 0.000	b	5.000 ± 0.289	b	3.000 ± 0.000	c	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	3.375 ± 0.072	fg
S14	6.000 ± 0.000	b	5.000 ± 0.000	c	4.000 ± 0.000	c	4.000 ± 0.000	b	3.000 ± 0.289	b	2.000 ± 0.289	b	2.000 ± 0.289	b	1.000 ± 0.000	b	3.375 ± 0.108	fg
S52	6.000 ± 0.577	b	5.000 ± 0.000	c	5.000 ± 0.000	b	3.000 ± 0.000	c	3.000 ± 0.000	b	2.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	b	3.375 ± 0.072	fg
S007	6.000 ± 0.000	b	5.000 ± 0.000	c	4.000 ± 0.000	c	3.000 ± 0.000	c	3.000 ± 0.000	b	2.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	b	3.25 ± 0.000	gh
S10	6.000 ± 0.289	b	5.000 ± 0.000	c	4.000 ± 0.577	c	3.000 ± 0.577	c	3.000 ± 0.000	b	2.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	b	3.25 ± 0.180	gh
291594	7.000 ± 0.000	b	5.000 ± 0.577	c	4.000 ± 0.000	c	3.000 ± 0.000	c	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	3.125 ± 0.072	ghi
300129	7.000 ± 0.000	b	5.000 ± 0.000	c	4.000 ± 0.000	c	3.000 ± 0.000	c	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	3.125 ± 0.000	ghi
300130	7.000 ± 0.000	b	5.000 ± 0.577	c	4.000 ± 0.289	c	3.000 ± 0.289	c	2.000 ± 0.289	c	2.000 ± 0.289	b	1.000 ± 0.000	c	1.000 ± 0.000	b	3.125 ± 0.253	ghi
S22	6.000 ± 0.000	b	6.000 ± 0.000	b	4.000 ± 0.000	c	3.000 ± 0.000	c	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	3.125 ± 0.000	ghi
S37	5.000 ± 0.577	c	4.000 ± 0.000	d	4.000 ± 0.000	c	3.000 ± 0.000	c	3.000 ± 0.000	b	2.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	b	3.125 ± 0.072	ghi
410364	6.000 ± 0.000	b	5.000 ± 0.000	c	4.000 ± 0.000	c	3.000 ± 0.000	c	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	3.000 ± 0.000	hij
674924-2	6.000 ± 0.289	b	5.000 ± 0.289	c	4.000 ± 0.000	c	3.000 ± 0.289	c	2.000 ± 0.289	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	3.000 ± 0.182	hij
S11	6.000 ± 0.000	b	4.000 ± 0.289	d	4.000 ± 0.289	c	3.000 ± 0.289	c	2.000 ± 0.000	c	2.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	b	3.000 ± 0.108	hij
S23	6.000 ± 0.000	b	5.000 ± 0.000	c	4.000 ± 0.000	c	3.000 ± 0.000	c	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	3.000 ± 0.000	hij
S53	6.000 ± 0.000	b	4.000 ± 0.000	d	4.000 ± 0.000	c	3.000 ± 0.000	c	2.000 ± 0.000	c	2.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	b	3.000 ± 0.000	hij
509038	6.000 ± 0.000	b	5.000 ± 0.000	c	3.000 ± 0.000	d	3.000 ± 0.000	c	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	2.875 ± 0.000	ijk
S006	5.000 ± 0.577	c	4.000 ± 0.000	d	4.000 ± 0.000	c	3.000 ± 0.289	c	2.000 ± 0.289	c	2.000 ± 0.289	b	2.000 ± 0.289	b	1.000 ± 0.000	b	2.875 ± 0.218	ijk
S46	5.000 ± 0.000	c	4.000 ± 0.000	d	4.000 ± 0.000	c	3.000 ± 0.000	c	2.000 ± 0.000	c	2.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	b	2.875 ± 0.000	ijk
S54	6.000 ± 0.577	b	4.000 ± 0.000	d	4.000 ± 0.000	c	3.000 ± 0.000	c	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	2.875 ± 0.072	ijk
410363	5.000 ± 0.000	c	5.000 ± 0.000	c	3.000 ± 0.000	d	3.000 ± 0.000	c	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	2.750 ± 0.000	jkl
S21	5.000 ± 0.000	c	4.000 ± 0.000	d	4.000 ± 0.000	c	3.000 ± 0.000	c	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	2.750 ± 0.000	jkl
S29	5.000 ± 0.000	c	5.000 ± 0.000	c	3.000 ± 0.289	d	3.000 ± 0.289	c	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	2.750 ± 0.072	jkl
S38	5.000 ± 0.000	c	5.000 ± 0.000	c	3.000 ± 0.000	d	2.000 ± 0.000	d	2.000 ± 0.000	c	2.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	b	2.750 ± 0.000	jkl
S44	4.000 ± 0.000	d	4.000 ± 0.000	d	3.000 ± 0.000	d	3.000 ± 0.000	c	2.000 ± 0.000	b	2.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	b	2.750 ± 0.000	jkl
S62	5.000 ± 0.577	c	4.000 ± 0.289	d	4.000 ± 0.289	c	3.000 ± 0.289	c	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	2.750 ± 0.180	jkl
S30	5.000 ± 0.000	c	4.000 ± 0.000	d	3.000 ± 0.000	d	3.000 ± 0.000	c	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	2.625 ± 0.000	klm
S47	6.000 ± 0.000	b	5.000 ± 0.577	c	4.000 ± 0.000	c	2.000 ± 0.000	d	1.000 ± 0.000	d	1.000 ± 0.000	c	1.000 ± 0.000	c	1.000 ± 0.000	b	2.625 ± 0.072	klm
S49	5.000 ± 0.577	c	4.000 ± 0.000	d	4.000 ± 0.000	c	3.000 ± 0.000	c	2.000 ± 0.000	c	1.000 ± 0.000	c	1.000 ± 0.000	c	1.000 ± 0.000	b	2.625 ± 0.072	klm
S55	4.000 ± 0.000	d	4.000 ± 0.000	d	3.000 ± 0.000	d	3.000 ± 0.000	c	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	2.5 ± 0.000	lmn
S005	6.000 ± 0.000	b	4.000 ± 0.000	d	3.000 ± 0.000	d	2.000 ± 0.000	d	1.000 ± 0.000	d	1.000 ± 0.000	c	1.000 ± 0.000	c	1.000 ± 0.000	b	2.375 ± 0.000	mn
S50	4.000 ± 0.000	d	4.000 ± 0.000	d	3.000 ± 0.577	d	3.000 ± 0.000	c	2.000 ± 0.000	c	1.000 ± 0.000	c	1.000 ± 0.000	c	1.000 ± 0.000	b	2.375 ± 0.072	mn
G001	4.000 ± 0.000	d	4.000 ± 0.000	d	3.000 ± 0.000	d	2.000 ± 0.000	d	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	2.375 ± 0.000	mn
S45	4.000 ± 0.000	d	3.000 ± 0.577	e	2.000 ± 0.000	e	2.000 ± 0.000	d	2.000 ± 0.000	c	2.000 ± 0.000	b	2.000 ± 0.000	b	1.000 ± 0.000	b	2.250 ± 0.072	n
S51	5.000 ± 0.577	c	4.000 ± 0.000	d	3.000 ± 0.000	d	2.000 ± 0.000	d	1.000 ± 0.000	d	1.000 ± 0.000	c	1.000 ± 0.000	c	1.000 ± 0.000	b	2.250 ± 0.072	n
S57	4.000 ± 0.577	d	3.000 ± 0.289	e	3.000 ± 0.289	d	2.000 ± 0.000	d	2.000 ± 0.000	c	2.000 ± 0.000	b	1.000 ± 0.000	c	1.000 ± 0.000	b	2.250 ± 0.144	n
S56	4.000 ± 0.289	d	3.000 ± 0.000	e	3.000 ± 0.000	d	2.000 ± 0.000	d	1.000 ± 0.000	d	1.000 ± 0.000	c	1.000 ± 0.000	c	1.000 ± 0.000	b	2.000 ± 0.036	n
S02	3.000 ± 0.577	e	2.000 ± 0.000	f	2.000 ± 0.000	e	1.000 ± 0.000	e	1.000 ± 0.000	d	1.000 ± 0.000	c	1.000 ± 0.000	c	1.000 ± 0.000	b	1.500 ± 0.072	o
S01	2.000 ± 0.000	f	2.000 ± 0.000	f	2.000 ± 0.000	e	1.000 ± 0.000	e	1.000 ± 0.000	d	1.000 ± 0.000	c	1.000 ± 0.000	c	1.000 ± 0.000	b	1.375 ± 0.000	o
S27	3.000 ± 0.000	e	2.000 ± 0.000	f	1.000 ± 0.000	f	1.000 ± 0.000	e	1.000 ± 0.000	d	1.000 ± 0.000	c	1.000 ± 0.000	c	1.000 ± 0.000	b	1.375 ± 0.000	o
S28	3.000 ± 0.000	e	2.000 ± 0.000	f	1.000 ± 0.000	f	1.000 ± 0.000	e	1.000 ± 0.000	d	1.000 ± 0.000	c	1.000 ± 0.000	c	1.000 ± 0.000	b	1.375 ± 0.000	o

Note: the word “Average” was abbreviated as Av. The significant differences among accessions in a same column is indicated by different letters.

Table 2

Coverage survey at the spring green-up.

Name	Cover (%)								Av. Cover (%)
	28 April		7 May		27 May		6 June
291594	60.000 ± 0.000	a	80.000 ± 0.012	a	98.000 ± 0.015	abc	100.000 ± 0.000	a	84.500 ± 0.007	a
S62	60.000 ± 0.010	a	70.000 ± 0.000	b	100.000 ± 0.000	a	100.000 ± 0.000	a	82.500 ± 0.003	ab
S13	60.000 ± 0.006	a	65.000 ± 0.020	c	98.000 ± 0.010	abc	100.000 ± 0.000	a	80.750 ± 0.009	bc
S58	60.000 ± 0.000	a	58.000 ± 0.020	e	100.000 ± 0.000	a	100.000 ± 0.000	a	79.500 ± 0.002	cd
S57	55.000 ± 0.020	b	63.000 ± 0.010	cd	93.000 ± 0.017	def	100.000 ± 0.000	a	77.750 ± 0.011	de
S08	50.000 ± 0.000	c	55.000 ± 0.029	e	99.000 ± 0.000	ab	100.000 ± 0.000	a	76.000 ± 0.007	ef
S006	50.000 ± 0.029	c	53.000 ± 0.015	ef	92.000 ± 0.017	defg	100.000 ± 0.000	a	73.750 ± 0.015	fg
S39	35.000 ± 0.000	f	60.000 ± 0.015	d	100.000 ± 0.000	a	100.000 ± 0.000	a	73.750 ± 0.004	fg
S47	40.000 ± 0.020	e	55.000 ± 0.012	e	100.000 ± 0.000	a	100.000 ± 0.000	a	73.750 ± 0.008	fg
S007	45.000 ± 0.000	d	54.000 ± 0.01	ef	90.000 ± 0.000	fg	100.000 ± 0.000	a	72.250 ± 0.003	gh
S25	35.000 ± 0.000	f	55.000 ± 0.000	e	93.000 ± 0.015	def	100.000 ± 0.000	a	70.750 ± 0.004	hi
S30	35.000 ± 0.029	f	55.000 ± 0.029	e	90.000 ± 0.000	fg	100.000 ± 0.000	a	70.000 ± 0.014	hi
S005	35.000 ± 0.000	f	50.000 ± 0.000	fg	94.000 ± 0.029	cdef	100.000 ± 0.000	a	69.750 ± 0.007	i
647924-2	30.000 ± 0.000	g	55.000 ± 0.000	e	90.000 ± 0.000	fg	100.000 ± 0.000	a	68.750 ± 0.000	i
S22	35.000 ± 0.000	f	50.000 ± 0.000	fg	90.000 ± 0.000	fg	100.000 ± 0.000	a	68.750 ± 0.000	i
S48	35.000 ± 0.000	f	50.000 ± 0.000	fg	90.000 ± 0.000	fg	100.000 ± 0.000	a	68.750 ± 0.000	i
674925-1	25.000 ± 0.029	h	60.000 ± 0.000	d	88.000 ± 0.029	gh	100.000 ± 0.000	a	68.250 ± 0.014	ij
S51	25.000 ± 0.000	h	52.000 ± 0.015	ef	96.000 ± 0.015	abcd	100.000 ± 0.000	a	68.250 ± 0.008	ij
S29	32.000 ± 0.015	fg	50.000 ± 0.000	fg	90.000 ± 0.000	fg	100.000 ± 0.000	a	68.000 ± 0.004	ijk
S52	30.000 ± 0.000	g	43.000 ± 0.015	hi	98.000 ± 0.012	abc	100.000 ± 0.000	a	67.750 ± 0.007	ijk
S54	30.000 ± 0.000	g	50.000 ± 0.000	fg	90.000 ± 0.000	fg	100.000 ± 0.000	a	67.500 ± 0.000	ijk
S37	30.000 ± 0.000	g	55.000 ± 0.029	e	88.000 ± 0.015	efg	96.000 ± 0.020	b	67.250 ± 0.022	ijk
S26	30.000 ± 0.000	g	45.000 ± 0.029	h	90.000 ± 0.000	fg	100.000 ± 0.000	a	66.250 ± 0.007	jkl
S23	20.000 ± 0.000	j	50.000 ± 0.000	fg	94.000 ± 0.015	cdef	100.000 ± 0.000	a	66.000 ± 0.004	jkl
S56	40.000 ± 0.000	e	47.000 ± 0.018	gh	85.000 ± 0.000	h	90.000 ± 0.000	c	65.500 ± 0.004	kl
S31	20.000 ± 0.000	j	45.000 ± 0.000	h	96.000 ± 0.015	abcd	100.000 ± 0.000	a	65.250 ± 0.004	kl
S50	25.000 ± 0.000	h	40.000 ± 0.000	ij	96.000 ± 0.020	abcd	100.000 ± 0.000	a	65.250 ± 0.005	lm
674924-2	15.000 ± 0.000	k	45.000 ± 0.029	h	100.000 ± 0.000	a	100.000 ± 0.000	a	65.000 ± 0.007	lm
S14	20.000 ± 0.000	j	60.000 ± 0.000	d	80.000 ± 0.000	i	100.000 ± 0.000	a	65.000 ± 0.000	lmn
S38	20.000 ± 0.000	j	40.000 ± 0.000	ij	100.000 ± 0.000	a	100.000 ± 0.000	a	65.000 ± 0.000	lmn
ST003	25.000 ± 0.029	h	35.000 ± 0.029	k	100.000 ± 0.000	a	100.000 ± 0.000	a	65.000 ± 0.014	lmn
S12	40.000 ± 0.000	e	38.000 ± 0.015	jk	80.000 ± 0.000	i	100.000 ± 0.000	a	64.500 ± 0.004	lmn
S04	10.000 ± 0.000	lm	45.000 ± 0.029	h	96.000 ± 0.010	abcd	100.000 ± 0.000	a	62.750 ± 0.009	mno
S55	20.000 ± 0.000	j	37.000 ± 0.015	jk	94.000 ± 0.006	cdef	100.000 ± 0.000	a	62.750 ± 0.005	no
S49	15.000 ± 0.000	k	40.000 ± 0.000	ij	90.000 ± 0.000	fg	100.000 ± 0.000	a	61.250 ± 0.000	op
G001	15.000 ± 0.000	k	35.000 ± 0.000	k	95.000 ± 0.000	bcde	100.000 ± 0.000	a	61.250 ± 0.000	op
S53	2.000 ± 0.010	op	38.000 ± 0.012	jk	99.000 ± 0.006	ab	100.000 ± 0.000	a	59.750 ± 0.007	p
S46	10.000 ± 0	lm	20.000 ± 0.000	n	96.000 ± 0.010	abcd	100.000 ± 0.000	a	56.500 ± 0.003	q
410363	8.000 ± 0.015	mn	25.000 ± 0.000	m	80.000 ± 0.000	i	100.000 ± 0.000	a	53.250 ± 0.004	r
300130	0.000 ± 0.000	p	35.000 ± 0.000	k	75.000 ± 0.000	j	100.000 ± 0.000	a	52.500 ± 0.000	r
509038	12 ± 0.015	kl	18.000 ± 0.015	no	80.000 ± 0.000	i	100.000 ± 0.000	a	52.500 ± 0.008	r
410364	1.000 ± 0.000	p	30.000 ± 0.000	l	70.000 ± 0.000	k	100.000 ± 0.000	a	50.250 ± 0.000	s
674925-3	5.000 ± 0.000	no	20.000 ± 0.000	n	70.000 ± 0.000	k	100.000 ± 0.000	a	48.750 ± 0.000	s
S21	15.000 ± 0.029	k	30.000 ± 0.029	l	60.000 ± 0.000	l	85.000 ± 0.000	d	47.500 ± 0.014	s
410361	10.000 ± 0.000	lm	30.000 ± 0.000	l	55.000 ± 0.029	m	80.000 ± 0.000	e	43.750 ± 0.007	t
S004	2.000 ± 0.010	op	10.000 ± 0.000	p	70.000 ± 0.000	k	90.000 ± 0.000	c	43.000 ± 0.003	t
S45	10.000 ± 0.000	lm	25.000 ± 0.029	m	55.000 ± 0.029	m	65.000 ± 0.029	f	38.750 ± 0.022	u
S11	5.000 ± 0.000	no	5.000 ± 0.000	q	45.000 ± 0.000	n	60.000 ± 0.000	g	28.750 ± 0.000	v
S44	5.000 ± 0.000	no	7.000 ± 0.006	pq	30.000 ± 0.000	o	40.000 ± 0.000	h	20.500 ± 0.001	w
300129	7.000 ± 0.017	mn	15.000 ± 0.000	o	20.000 ± 0.000	p	35.000 ± 0.000	i	19.250 ± 0.004	w
S01	2.000 ± 0.000	op	8.000 ± 0.015	pq	25.000 ± 0.000	o	40.000 ± 0.000	h	18.750 ± 0.004	w
S27	2.000 ± 0.010	op	8.000 ± 0.010	pq	30.000 ± 0.000	o	35.000 ± 0.000	i	18.750 ± 0.005	w
S02	2.000 ± 0.000	op	6.000 ± 0.006	pq	15.000 ± 0.000	q	30.000 ± 0.000	j	13.250 ± 0.001	x
S10	0.000 ± 0.000	p	5.000 ± 0.000	q	15.000 ± 0.000	q	25.000 ± 0.000	k	11.250 ± 0.000	y
S28	1.000 ± 0.000	p	5.000 ± 0.000	q	10.000 ± 0.000	r	20.000 ± 0.000	l	9.000 ± 0.000	y

Note: the word “Average” was abbreviated as Av. The significant differences among accessions in a same column is indicated by different letters.

Table 3

Membership function analysis based on pot experiment results. Note: the word “Average” was abbreviated as Av. The significant differences among accessions in a same column is indicated by different letters.

Accession	Av. Greenness		Av. Coverage		Score		Rank
ST003	1.000 ± 0.000	a	0.741 ± 0.012	m	0.871 ± 0.006	a	1
S13	0.742 ± 0.066	cd	0.950 ± 0.004	c	0.846 ± 0.032	ab	2
S12	0.927 ± 0.027	ab	0.735 ± 0.001	m	0.831 ± 0.014	abc	3
S08	0.771 ± 0.013	cd	0.887 ± 0.002	e	0.829 ± 0.005	abcd	4
674925-1	0.853 ± 0.043	bc	0.784 ± 0.012	ijk	0.819 ± 0.015	abcd	5
S39	0.777 ± 0.047	cd	0.857 ± 0.002	f	0.817 ± 0.025	abcd	6
S58	0.697 ± 0.028	de	0.925 ± 0.006	d	0.811 ± 0.017	bcd	7
S25	0.771 ± 0.013	cd	0.817 ± 0.002	gh	0.794 ± 0.007	bcde	8
S48	0.775 ± 0.036	cd	0.791 ± 0.006	ijk	0.783 ± 0.021	cde	9
291594	0.543 ± 0.026	fgh	1.000 ± 0.000	a	0.771 ± 0.013	de	10
S26	0.742 ± 0.066	cd	0.758 ± 0.003	lm	0.750 ± 0.031	ef	11
S04	0.777 ± 0.047	cd	0.711 ± 0.006	n	0.744 ± 0.021	ef	12
S31	0.742 ± 0.066	cd	0.745 ± 0.001	m	0.743 ± 0.034	ef	13
S007	0.586 ± 0.052	efg	0.837 ± 0.004	fg	0.712 ± 0.028	fg	14
647924-2	0.621 ± 0.033	ef	0.791 ± 0.006	ijk	0.706 ± 0.021	fgh	15
S52	0.621 ± 0.033	ef	0.778 ± 0.001	kl	0.699 ± 0.015	fgh	16
S62	0.419 ± 0.018	hijkl	0.973 ± 0.005	b	0.696 ± 0.006	fgh	17
674925-3	0.855 ± 0.054	bc	0.526 ± 0.004	rs	0.691 ± 0.029	fghi	18
S14	0.619 ± 0.021	ef	0.741 ± 0.006	m	0.681 ± 0.014	ghij	19
S22	0.547 ± 0.049	fgh	0.791 ± 0.006	ijk	0.669 ± 0.028	ghijk	20
S37	0.543 ± 0.026	fgh	0.782 ± 0.022	jk	0.662 ± 0.002	ghijkl	21
S006	0.443 ± 0.029	hijk	0.857 ± 0.012	f	0.651 ± 0.021	hijklm	22
410361	0.810 ± 0.016	cd	0.460 ± 0.005	t	0.635 ± 0.005	ijklmn	23
S23	0.508 ± 0.045	fghij	0.754 ± 0.001	lm	0.631 ± 0.023	jklmn	24
S47	0.394 ± 0.057	ijklm	0.857 ± 0.002	f	0.626 ± 0.027	jklmn	25
S54	0.464 ± 0.019	ghijk	0.774 ± 0.006	kl	0.619 ± 0.013	klmn	26
S004	0.777 ± 0.047	cd	0.450 ± 0.001	t	0.613 ± 0.024	klmno	27
674924-2	0.484 ± 0.015	ghij	0.741 ± 0.003	m	0.613 ± 0.008	klmno	28
S29	0.425 ± 0.015	hijkl	0.781 ± 0.001	jk	0.603 ± 0.008	lmnop	29
S30	0.390 ± 0.035	jklmn	0.807 ± 0.012	hi	0.599 ± 0.011	mnop	30
S53	0.508 ± 0.045	fghij	0.672 ± 0.002	o	0.590 ± 0.021	mnopq	31
S57	0.265 ± 0.021	op	0.910 ± 0.007	d	0.587 ± 0.014	nopq	32
S38	0.429 ± 0.038	hijkl	0.741 ± 0.006	m	0.585 ± 0.022	nopqr	33
S005	0.312 ± 0.028	lmno	0.804 ± 0.002	hij	0.558 ± 0.012	opqrs	34
S46	0.468 ± 0.042	ghijk	0.629 ± 0.002	p	0.549 ± 0.022	pqrs	35
300130	0.519 ± 0.033	fghi	0.576 ± 0.005	q	0.548 ± 0.014	pqrs	36
S49	0.386 ± 0.012	jklmn	0.692 ± 0.006	no	0.539 ± 0.009	qrs	37
S55	0.351 ± 0.031	klmno	0.711 ± 0.001	n	0.531 ± 0.015	qrs	38
410364	0.508 ± 0.045	fghij	0.546 ± 0.004	r	0.527 ± 0.025	rst	39
S51	0.269 ± 0.001	no	0.784 ± 0.003	ijk	0.527 ± 0.001	rst	40
S50	0.308 ± 0.005	lmno	0.745 ± 0.002	m	0.526 ± 0.003	rst	41
509038	0.468 ± 0.042	ghijk	0.576 ± 0.005	q	0.522 ± 0.018	st	42
410363	0.429 ± 0.038	hijkl	0.586 ± 0.001	q	0.508 ± 0.019	st	43
G001	0.312 ± 0.028	lmno	0.692 ± 0.006	no	0.502 ± 0.017	st	44
S56	0.193 ± 0.006	p	0.748 ± 0.001	m	0.471 ± 0.003	t	45
S21	0.429 ± 0.038	hijkl	0.509 ± 0.014	s	0.469 ± 0.012	t	46
S11	0.502 ± 0.011	fghij	0.261 ± 0.002	v	0.381 ± 0.006	u	47
300129	0.547 ± 0.049	fgh	0.135 ± 0.004	w	0.341 ± 0.022	uv	48
S45	0.277 ± 0.047	mno	0.393 ± 0.025	u	0.335 ± 0.011	uv	49
S10	0.576 ± 0.004	gf	0.029 ± 0.001	y	0.302 ± 0.002	v	50
S44	0.429 ± 0.038	hijkl	0.152 ± 0.001	w	0.291 ± 0.019	v	51
S01	0.000 ± 0.000	q	0.129 ± 0.003	wx	0.064 ± 0.001	w	52
S27	0.000 ± 0.000	q	0.129 ± 0.005	x	0.064 ± 0.002	w	53
S02	0.035 ± 0.019	q	0.056 ± 0.001	x	0.045 ± 0.011	wx	54
S28	0.000 ± 0.000	q	0.000 ± 0.000	z	0.000 ± 0.000	x	55

Table 4

Leaf LT50.

Name	Fitted Equation	R2	LT50
S39	Y = 0.0001214257/(0.726933e(0.9834X) + 0.000167)	0.9962	−9.322
S005	Y = 0.00009260336/(0.99510695e(1.062X) + 0.00009305)	0.9936	−8.744
410364	Y = 0.000057860928/(0.99514186e(1.128X) + 0.00005814)	0.9938	−8.651
674925-1	Y = 0.00012980552/(0.9599648e(1.041X) + 0.0001352)	0.9953	−8.598
S22	Y = 0.009776992/(0.87537e(0.5697X) + 0.01103)	0.9388	−8.130
S25	Y = 0.0060481639/(0.856899e(0.6375X) + 0.007001)	0.9382	−8.039
S30	Y = 0.000074015504/(0.98732504e(1.254X) + 0.00007496)	0.9932	−7.584
S14	Y = 0.00101304/(1.003992e(0.9263X) + 0.001008)	0.9303	−7.442
S13	Y = 0.001925836/(1.010097e(0.8403X) + 0.001903)	0.9207	−7.431
S55	Y = 0.00072324/(1.0072825e(0.9924X) + 0.0007175)	0.9509	−7.286
509038	Y = 0.0319708/(0.9969e(0.518X) + 0.0311)	0.9763	−6.588
S47	Y = 0.244601/(0.9515e(0.2011X) + 0.2105)	0.951	−6.105
s46	Y = 0.034527/(0.98615e(0.5549X)+0.03385)	0.9939	−6.005
410363	Y = 0.0050289084/(0.886966e(1.136X) + 0.005634)	0.9972	−4.666
S57	Y = 0.004862/(0.995138e(1.165X) + 0.004862)	0.9906	−4.567
300130	Y = 0.002255/(0.997745e(1.455X) + 0.002255)	0.996	−4.187
G001	Y = 0.05019384/(0.93299e(0.7484X) + 0.05101)	0.9973	−3.926
S51	Y = 0.11036856/(0.841e(0.5361X) + 0.1154)	0.9734	−3.875
S58	Y = 0.2392359/(0.8063e(0.3166X) + 0.2307)	0.9029	−3.726
ST003	Y = 0.14605676/(0.8111e(−0.4706X) + 0.1517)	0.9755	−3.726
674925-3	Y = 0.251808/(0.788e(0.306X) + 0.244)	0.9965	−3.628
647924-2	Y = 0.2639386/(0.7887e(−0.2983X) + 0.2533)	0.9962	−3.537
S04	Y = 0.01177386/(0.9775e(1.343X) + 0.0119)	0.9986	−3.298
S02	Y = 0.02462/(0.97538e(1.119X) + 0.02462)	0.999	−3.287
S26	Y = 0.29094953/(0.6728e(0.2717X) + 0.2993)	0.945	−3.192
S29	Y = 0.081644706/(0.87528e(0.778X) + 0.08502)	0.9446	−3.103
S31	Y = 0.00738243/(0.982543e(1.627X) + 0.007457)	0.9968	−3.012
410361	Y = 0.019615484/(0.97498e(1.302X) + 0.01972)	0.9963	−3.004
S44	Y = 0.0661362/(0.8303e(0.8921X) + 0.0732)	0.9909	−2.962
S48	Y = 0.038806316/(0.94997e(1.092X) + 0.03923)	0.9937	−2.938
S49	Y = 0.016183542/(0.96979e(−1.436X)+0.01641)	0.975	−2.860
S01	Y = 0.06156948/(0.92834e(0.9526X) + 0.06216)	0.9834	−2.858
674924-2	Y = 0.12187968/(0.8518e(0.6895X) + 0.1248)	0.9736	−2.855
S23	Y = 0.049398912/(0.93632e(1.055X) + 0.05008)	0.9893	−2.801
S52	Y = 0.4486097/(0.8117e(0.1628X) + 0.3773)	0.9669	−2.736
S08	Y = 0.16656668/(0.8332e(0.6524X) + 0.1666)	0.9569	−2.467
S004	Y = 0.1205039/(0.8749e(0.8163X) + 0.121)	0.9124	−2.433
S53	Y = 0.054600213/(0.94213e(1.266X) + 0.05477)	0.9529	−2.252
291594	Y = 0.37764/(0.689e(0.2548X) + 0.36)	0.977	−2.181
S007	Y = 0.033322732/(0.96213e(1.551X) + 0.03347)	0.9852	−2.171
S38	Y = 0.23126787/(0.7486e(0.5685X) + 0.2351)	0.9767	−2.095
S12	Y = 0.18992891/(0.809e(0.736X) + 0.1901)	0.9566	−1.971
S54	Y = 0.27675508/(0.5583e(0.4981X) + 0.3164)	0.9954	−1.719
S45	Y = 0.3547992/(0.6842e(0.3752X) + 0.3448)	0.9328	−1.676
300129	Y = 0.335682/(0.6909e(0.4776X) + 0.3291)	0.9623	−1.471
S62	Y = 0.393151/(0.6483e(0.3226X) + 0.3817)	0.9171	−1.461
S37	Y = 0.4515098/(0.6016e(0.2602X) + 0.4354)	0.9082	−0.968
S50	Y = 0.4506476/(0.5882e(0.2879X) + 0.4388)	0.9715	−0.835
S56	Y = 0.4829058/(0.5944e(0.275X) + 0.4586)	0.8743	−0.576
S28	Y = 0.50284/(0.5565e(−0.2231X) + 0.4835)	0.9411	−0.285
S10	Y = 0.5437773/(0.5721e(0.2231X) + 0.5049)	0.8281	0.081
S21	Y = 0.5490298/(0.5151e(0.2924X) + 0.5269)	0.9247	0.353
S11	Y = 0.5569336/(0.5256e(0.2513X) + 0.5284)	0.9165	0.429
S006	Y = 0.6057768/(0.4544e(0.207X) + 0.5836)	0.9358	1.562
S27	Y = 0.7050042/(0.4224e(0.1686X) + 0.6546)	0.8635	3.447

Table 5

Stolon regrowth ability post-low-temperature treatment.

Name	Regrowth Ratio (%)									Relative Regrowth Rate (%)						Total Relative Regrowth Rate (%)
	8 °C		3 °C		−2 °C		−7 °C		−12 °C	3 °C		2 °C		−7 °C
S30	46.000 ± 0.033	abc	36.000 ± 0.033	bc	26.000 ± 0.033	ab	10.000 ± 0.000	a	0.000 ± 0.000	78.000 ± 0.032	cd	57.000 ± 0.054	abc	22.000 ± 0.021	a	52.000 ± 0.058	a
S39	50.000 ± 0.057	ab	40.000 ± 0.100	ab	26.000 ± 0.066	ab	10.000 ± 0.100	a	0.000 ± 0.000	80.000 ± 0.036	bc	52.000 ± 0.045	bcdef	20.000 ± 0.036	ab	51.000 ± 0.014	ab
S25	40.000 ± 0.100	cd	36.000 ± 0.033	bc	20.000 ± 0.000	abcd	3.000 ± 0.033	ab	0.000 ± 0.000	90.000 ± 0.052	a	50.000 ± 0.078	cdefg	8.000 ± 0.069	abc	49.000 ± 0.064	bc
S55	40.000 ± 0.000	cd	36.000 ± 0.066	bc	23.000 ± 0.033	abc	0.000 ± 0.000	b	0.000 ± 0.000	90.000 ± 0.032	a	58.000 ± 0.021	ab	0.000 ± 0.031	c	49.000 ± 0.036	bc
S13	53.000 ± 0.033	a	46.000 ± 0.033	a	26.000 ± 0.088	ab	3.000 ± 0.033	ab	0.000 ± 0.000	87.000 ± 0.058	ab	49.000 ± 0.065	defg	6.000 ± 0.066	bc	47.000 ± 0.067	c
410364	46.000 ± 0.088	abc	36.000 ± 0.033	bc	26.000 ± 0.066	ab	3.000 ± 0.033	ab	0.000 ± 0.000	78.000 ± 0.088	cd	57.000 ± 0.021	abc	7.000 ± 0.025	abc	47.000 ± 0.065	c
S14	50.000 ± 0.057	ab	40.000 ± 0.056	ab	30.000 ± 0.057	a	0.000 ± 0.000	b	0.000 ± 0.000	80.000 ± 0.065	bc	60.000 ± 0.054	a	0.000 ± 0.000	c	47.000 ± 0.069	c
S31	30.000 ± 0.033	ef	26.000 ± 0.033	def	16.000 ± 0.033	abcde	0.000 ± 0.000	b	0.000 ± 0.000	87.000 ± 0.037	ab	53.000 ± 0.088	abcde	0.000 ± 0.000	c	47.000 ± 0.056	c
S22	50.000 ± 0.057	ab	40.000 ± 0.056	ab	20.000 ± 0.032	abcd	6.000 ± 0.033	ab	0.000 ± 0.000	80.000 ± 0.041	bc	40.000 ± 0.056	hijk	12.000 ± 0.032	abc	44.000 ± 0.044	d
674925-1	46.000 ± 0.066	abc	30.000 ± 0.098	cde	20.000 ± 0.057	abcd	10.000 ± 0.100	a	0.000 ± 0.000	65.000 ± 0.012	ghi	43.000 ± 0.032	ghij	22.000 ± 0.021	a	43.000 ± 0.021	d
291594	30.000 ± 0.000	ef	26.000 ± 0.088	def	13.000 ± 0.033	abcde	0.000 ± 0.000	b	0.000 ± 0.000	87.000 ± 0.037	ab	43.000 ± 0.036	ghij	0.000 ± 0.000	c	43.000 ± 0.032	d
S58	30.000 ± 0.057	ef	23.000 ± 0.033	efg	16.000 ± 0.033	abcde	0.000 ± 0.000	b	0.000 ± 0.000	77.000 ± 0.077	cde	53.000 ± 0.088	abcde	0.000 ± 0.000	c	43.000 ± 0.032	d
ST003	40.000 ± 0.100	cd	36.000 ± 0.033	bc	16.000 ± 0.033	abcde	0.000 ± 0.000	b	0.000 ± 0.000	90.000 ± 0.032	a	40.000 ± 0.022	hijk	0.000 ± 0.000	c	43.000 ± 0.024	d
674925-3	36.000 ± 0.066	de	26.000 ± 0.033	def	20.000 ± 0.057	abcd	0.000 ± 0.000	b	0.000 ± 0.000	72.000 ± 0.032	def	56.000 ± 0.032	abcd	0.000 ± 0.000	c	43.000 ± 0.024	d
S006	30.000 ± 0.000	ef	20.000 ± 0.023	fh	16.000 ± 0.033	abcde	0.000 ± 0.000	b	0.000 ± 0.000	67.000 ± 0.054	fghi	53.000 ± 0.088	abcde	0.000 ± 0.000	c	40.000 ± 0.054	e
410363	43.000 ± 0.066	bcd	30.000 ± 0.100	cde	20.000 ± 0.057	abcd	0.000 ± 0.000	b	0.000 ± 0.000	70.000 ± 0.035	efgh	47.000 ± 0.023	efgh	0.000 ± 0.000	c	39.000 ± 0.054	ef
S56	26.000 ± 0.033	fg	20.000 ± 0.100	fh	10.000 ± 0.057	bcde	0.000 ± 0.000	b	0.000 ± 0.000	77.000 ± 0.078	cd	38.000 ± 0.041	ijkl	0.000 ± 0.000	c	38.000 ± 0.045	efg
S005	50.000 ± 0.100	ab	33.000 ± 0.033	bcd	23.000 ± 0.033	abc	0.000 ± 0.000	b	0.000 ± 0.000	66.000 ± 0.065	fghi	46.000 ± 0.054	fgh	0.000 ± 0.000	c	37.000 ± 0.023	fg
S47	50.000 ± 0.100	ab	36.000 ± 0.133	bc	20.000 ± 0.100	abcd	0.000 ± 0.000	b	0.000 ± 0.000	72.000 ± 0.033	defg	40.000 ± 0.022	hijk	0.000 ± 0.000	c	37.000 ± 0.065	fg
G001	30.000 ± 0.320	ef	23.000 ± 0.088	efg	10.000 ± 0.057	bcde	0.000 ± 0.000	b	0.000 ± 0.000	77.000 ± 0.057	cde	33.000 ± 0.014	klm	0.000 ± 0.000	c	37.000 ± 0.047	fg
S50	36.000 ± 0.066	de	26.000 ± 0.033	def	13.000 ± 0.066	abcde	0.000 ± 0.000	b	0.000 ± 0.000	72.000 ± 0.023	def	36.000 ± 0.036	kl	0.000 ± 0.000	c	36.000 ± 0.054	g
S51	36.000 ± 0.066	de	26.000 ± 0.033	def	13.000 ± 0.066	abcde	0.000 ± 0.000	b	0.000 ± 0.000	72.000 ± 0.054	def	36.000 ± 0.054	kl	0.000 ± 0.000	c	36.000 ± 0.054	g
S54	30.000 ± 0.054	ef	26.000 ± 0.033	def	6.666 ± 0.033	cde	0.000 ± 0.000	b	0.000 ± 0.000	87.000 ± 0.036	ab	20.000 ± 0.059	n	0.000 ± 0.000	c	36.000 ± 0.064	g
S02	36.000 ± 0.133	de	26.000 ± 0.066	def	10.000 ± 0.057	bcde	0.000 ± 0.000	b	0.000 ± 0.000	72.000 ± 0.023	def	28.000 ± 0.023	m	0.000 ± 0.000	c	33.000 ± 0.033	h
S08	36.000 ± 0.033	de	30.000 ± 0.098	cde	6.000 ± 0.066	cde	0.000 ± 0.000	b	0.000 ± 0.000	83.000 ± 0.054	abc	17.000 ± 0.032	n	0.000 ± 0.000	c	33.000 ± 0.057	h
S23	36.000 ± 0.066	de	26.000 ± 0.066	def	10.000 ± 0.057	bcde	0.000 ± 0.000	b	0.000 ± 0.000	72.000 ± 0.023	def	28.000 ± 0.036	m	0.000 ± 0.000	c	33.000 ± 0.036	h
S37	20.000 ± 0.021	g	10.000 ± 0.021	h	10.000 ± 0.100	bcde	0.000 ± 0.000	b	0.000 ± 0.000	50.000 ± 0.054	m	50.000 ± 0.078	cdefg	0.000 ± 0.000	c	33.000 ± 0.035	h
S44	36.000 ± 0.033	de	20.000 ± 0.100	fh	16.000 ± 0.033	abcde	0.000 ± 0.000	b	0.000 ± 0.000	56.000 ± 0.036	klm	44.000 ± 0.064	ghi	0.000 ± 0.000	c	33.000 ± 0.025	h
S48	30.000 ± 0.057	ef	20.000 ± 0.000	fh	10.000 ± 0.054	bcde	0.000 ± 0.000	b	0.000 ± 0.000	67.000 ± 0.023	fghi	33.000 ± 0.014	klm	0.000 ± 0.000	c	33.000 ± 0.014	h
300130	43.000 ± 0.033	bcd	26.000 ± 0.066	def	16.000 ± 0.088	abcd	0.000 ± 0.000	b	0.000 ± 0.000	60.000 ± 0.036	ijk	37.000 ± 0.056	jkl	0.000 ± 0.000	c	33.000 ± 0.025	h
410361	36.000 ± 0.033	de	20.000 ± 0.057	fh	13.000 ± 0.033	abcde	0.000 ± 0.000	b	0.000 ± 0.000	56.000 ± 0.021	klm	36.000 ± 0.032	kl	0.000 ± 0.000	c	31.000 ± 0.023	hi
S29	36.000 ± 0.033	de	20.000 ± 0.100	fh	13.000 ± 0.033	abcde	0.000 ± 0.000	b	0.000 ± 0.000	56.000 ± 0.025	klm	36.000 ± 0.025	kl	0.000 ± 0.000	c	31.000 ± 0.065	hi
S49	36.000 ± 0.133	de	20.000 ± 0.023	fh	13.000 ± 0.033	abcde	0.000 ± 0.000	b	0.000 ± 0.000	56.000 ± 0.025	klm	36.000 ± 0.021	kl	0.000 ± 0.000	c	31.000 ± 0.021	hi
509038	46.000 ± 0.033	abc	26.000 ± 0.033	def	16.000 ± 0.033	abcde	0.000 ± 0.000	b	0.000 ± 0.000	57.000 ± 0.065	klm	35.000 ± 0.057	kl	0.000 ± 0.000	c	30.000 ± 0.035	hij
S46	46.000 ± 0.066	abc	26.000 ± 0.088	def	16.000 ± 0.088	abcde	0.000 ± 0.000	b	0.000 ± 0.000	57.000 ± 0.041	klm	35.000 ± 0.36	kl	0.000 ± 0.000	c	30.000 ± 0.025	hij
S57	40.000 ± 0.100	cd	23.000 ± 0.033	efg	13.000 ± 0.033	abcde	0.000 ± 0.000	b	0.000 ± 0.000	58.000 ± 0.023	jkl	33.000 ± 0.014	lm	0.000 ± 0.000	c	30.000 ± 0.054	hij
674924-2	36.000 ± 0.033	de	26.000 ± 0.133	def	6.000 ± 0.066	cde	0.000 ± 0.000	b	0.000 ± 0.000	72.000 ± 0.045	def	17.000 ± 0.025	n	0.000 ± 0.000	c	30.000 ± 0.036	hij
S004	30.000 ± 0.000	ef	16.000 ± 0.033	g	10.000 ± 0.057	bcde	0.000 ± 0.000	b	0.000 ± 0.000	53.000 ± 0.069	lm	33.000 ± 0.045	klm	0.000 ± 0.000	c	29.000 ± 0.031	ij
S01	30.000 ± 0.000	ef	16.000 ± 0.033	g	10.000 ± 0.057	bcde	0.000 ± 0.000	b	0.000 ± 0.000	53.000 ± 0.047	lm	33.000 ± 0.025	klm	0.000 ± 0.000	c	29.000 ± 0.025	ij
S21	30.000 ± 0.000	ef	20.000 ± 0.013	fh	6.000 ± 0.033	cde	0.000 ± 0.000	b	0.000 ± 0.000	67.000 ± 0.014	fghi	20.000 ± 0.056	n	0.000 ± 0.000	c	29.000 ± 0.021	ij
S26	30.000 ± 0.000	ef	16.000 ± 0.033	g	10.000 ± 0.000	bcde	0.000 ± 0.000	b	0.000 ± 0.000	53.000 ± 0.021	lm	33.000 ± 0.014	klm	0.000 ± 0.000	c	29.000 ± 0.021	ij
S38	30.000 ± 0.100	ef	20.000 ± 0.023	fh	6.000± 0.033	cde	0.000 ± 0.000	b	0.000 ± 0.000	67.000 ± 0.023	fghi	20.000 ± 0.056	n	0.000 ± 0.000	c	29.000 ± 0.023	ij
S52	30.000 ± 0.100	ef	16.000 ± 0.033	g	10.000 ± 0.023	bcde	0.000 ± 0.000	b	0.000 ± 0.000	53.000 ± 0.056	lm	33.000 ± 0.014	klm	0.000 ± 0.000	c	29.000 ± 0.025	ij
647924-2	36.000 ± 0.033	de	16.000 ± 0.033	g	13.000 ± 0.033	abcde	0.000 ± 0.000	b	0.000 ± 0.000	44.000 ± 0.025	m	36.000 ± 0.054	kl	0.000 ± 0.000	c	27.000 ± 0.014	j
S53	40.000 ± 0.052	cd	16.000 ± 0.033	g	16.000 ± 0.066	abcde	0.000 ± 0.000	b	0.000 ± 0.000	40.000 ± 0.036	mn	40.000 ± 0.036	hijk	0.000 ± 0.000	c	27.000 ± 0.036	j
S62	20.000 ± 0.021	g	16.000 ± 0.033	g	0.000 ± 0.000	e	0.000 ± 0.000	b	0.000 ± 0.000	80.000 ± 0.054	bc	0.000 ± 0.000	p	0.000 ± 0.000	c	27.000 ± 0.054	j
S007	36.000 ± 0.033	de	16.000 ± 0.033	g	10.000 ± 0.100	bcde	0.000 ± 0.000	b	0.000 ± 0.000	44.000 ± 0.023	m	28.000 ± 0.025	m	0.000 ± 0.000	c	24.000 ± 0.021	k
S12	36.000 ± 0.133	de	23.000 ± 0.066	efg	3.000 ± 0.033	de	0.000 ± 0.000	b	0.000 ± 0.000	64.000 ± 0.036	hij	8.000 ± 0.036	o	0.000 ± 0.000	c	24.000 ± 0.036	k
S28	30.000 ± 0.054	ef	20.000 ± 0.045	fh	0.000 ± 0.000	e	0.000 ± 0.000	b	0.000 ± 0.000	67.000 ± 0.025	fghi	0.000 ± 0.000	p	0.000 ± 0.000	c	22.000 ± 0.000	k
S45	30.000 ± 0.100	ef	20.000 ± 0.100	fh	0.000 ± 0.000	e	0.000 ± 0.000	b	0.000 ± 0.000	67.000 ± 0.056	fghi	0.000 ± 0.000	p	0.000 ± 0.000	c	22.000 ± 0.056	k
S04	40.000 ± 0.052	cd	20.000 ± 0.000	fh	6.000 ± 0.033	cde	0.000 ± 0.000	b	0.000 ± 0.000	50.000 ± 0.054	m	15.000 ± 0.025	n	0.000 ± 0.000	c	22.000 ± 0.021	k
S11	26.000 ± 0.066	fg	16.000 ± 0.033	g	0.000 ± 0.000	e	0.000 ± 0.000	b	0.000 ± 0.000	62.000 ± 0.023	ijk	0.000 ± 0.000	p	0.000 ± 0.000	c	21.000 ± 0.023	k
S27	26.000 ± 0.066	fg	16.000 ± 0.033	g	0.000 ± 0.000	e	0.000 ± 0.000	b	0.000 ± 0.000	62.000 ± 0.056	ijk	0.000 ± 0.000	p	0.000 ± 0.000	c	21.000 ± 0.056	k
S10	26.000 ± 0.066	fg	13.000 ± 0.033	gh	0.000 ± 0.000	e	0.000 ± 0.000	b	0.000 ± 0.000	50.000 ± 0.054	m	0.000 ± 0.000	p	0.000 ± 0.000	c	17.000 ± 0.054	l
300129	26.000 ± 0.120	fg	10.000 ± 0.000	h	0.000 ± 0.000	e	0.000 ± 0.000	b	0.000 ± 0.000	38.000 ± 0.000	n	0.000 ± 0.000	p	0.000 ± 0.000	c	13.000 ± 0.000	m

Note: The significant differences among accessions in a same column is indicated by different letters.

Table 6

Membership function analysis based on laboratory results. The significant differences among accessions in a same column is indicated by different letters.

Accession	LT50	Total Relative Regrowth Rate		Score		Rank
S39	1.000 ± 0.000	0.974 ± 0.014	ab	0.987 ± 0.007	a	1
S30	0.863 ± 0.000	1.000 ± 0.000	a	0.931 ± 0.000	b	2
S25	0.899 ± 0.000	0.923 ± 0.001	bc	0.911 ± 0.001	bc	3
410364	0.947 ± 0.000	0.871 ± 0.026	c	0.909 ± 0.013	bc	4
S55	0.841 ± 0.000	0.922 ± 0.026	bc	0.881 ± 0.013	cd	5
S14	0.852 ± 0.000	0.872 ± 0.023	c	0.862 ± 0.011	d	6
S13	0.852 ± 0.000	0.872 ± 0.012	c	0.862 ± 0.006	d	7
674925-1	0.943 ± 0.000	0.768 ± 0.031	d	0.856 ± 0.015	d	8
S22	0.906 ± 0.000	0.795 ± 0.022	d	0.851 ± 0.011	d	9
S005	0.954 ± 0.000	0.616 ± 0.023	fg	0.785 ± 0.011	e	10
S31	0.505 ± 0.000	0.871 ± 0.031	c	0.688 ± 0.015	f	11
S47	0.748 ± 0.000	0.615 ± 0.005	fg	0.681 ± 0.002	fg	12
S58	0.561 ± 0.000	0.771 ± 0.062	d	0.666 ± 0.031	fg	13
ST003	0.561 ± 0.000	0.769 ± 0.003	d	0.665 ± 0.001	fg	14
674925-3	0.554 ± 0.000	0.769 ± 0.023	d	0.661 ± 0.011	fg	15
410363	0.635 ± 0.000	0.667 ± 0.024	ef	0.651 ± 0.012	g	16
509038	0.785 ± 0.000	0.436 ± 0.019	ijk	0.611 ± 0.009	h	17
291594	0.441 ± 0.000	0.768 ± 0.041	d	0.604 ± 0.021	h	18
G001	0.577 ± 0.000	0.615 ± 0.021	fg	0.596 ± 0.011	h	19
S46	0.740 ± 0.000	0.435 ± 0.008	ijk	0.587 ± 0.004	h	20
S51	0.573 ± 0.000	0.591 ± 0.023	g	0.581 ± 0.011	hi	21
300130	0.597 ± 0.000	0.512 ± 0.012	h	0.555 ± 0.006	ij	22
S57	0.627 ± 0.000	0.436 ± 0.018	ijk	0.531 ± 0.009	jk	23
S02	0.527 ± 0.000	0.512 ± 0.012	h	0.521 ± 0.006	jkl	24
S44	0.501 ± 0.000	0.513 ± 0.021	hi	0.507 ± 0.011	klm	25
S48	0.501 ± 0.000	0.512 ± 0.007	hi	0.506 ± 0.003	klm	26
S23	0.489 ± 0.000	0.513 ± 0.022	hi	0.501 ± 0.011	klmn	27
S54	0.404 ± 0.000	0.590 ± 0.021	g	0.497 ± 0.011	klmn	28
S49	0.493 ± 0.000	0.486 ± 0.007	hij	0.491 ± 0.003	lmno	29
S08	0.463 ± 0.000	0.512 ± 0.007	hi	0.487 ± 0.003	lmno	30
S29	0.512 ± 0.000	0.462 ± 0.021	hijk	0.487 ± 0.011	lmno	31
410361	0.505 ± 0.000	0.461 ± 0.007	hijk	0.483 ± 0.003	mnopq	32
S26	0.519 ± 0.000	0.436 ± 0.018	ijk	0.478 ± 0.009	mnopq	33
S56	0.315 ± 0.000	0.641 ± 0.005	efg	0.478 ± 0.002	mnopq	34
674924-2	0.493 ± 0.000	0.435 ± 0.012	ijk	0.464 ± 0.006	nopqr	35
S50	0.335 ± 0.000	0.589 ± 0.006	g	0.462 ± 0.003	nopqr	36
647924-2	0.546 ± 0.000	0.359 ± 0.017	l	0.453 ± 0.008	opqrs	37
S01	0.493 ± 0.000	0.410 ± 0.021	jkl	0.452 ± 0.011	pqrs	38
S52	0.484 ± 0.000	0.411 ± 0.018	kl	0.447 ± 0.009	qrs	39
S004	0.461 ± 0.000	0.410 ± 0.018	kl	0.435 ± 0.009	rst	40
S38	0.434 ± 0.000	0.435 ± 0.012	ijk	0.434 ± 0.006	rst	41
S37	0.345 ± 0.000	0.513 ± 0.021	hi	0.429 ± 0.011	rst	42
S006	0.147 ± 0.000	0.693 ± 0.071	e	0.420 ± 0.035	st	43
S53	0.446 ± 0.000	0.358 ± 0.013	l	0.402 ± 0.006	tu	44
S04	0.528 ± 0.000	0.231 ± 0.003	m	0.379 ± 0.001	uv	45
S62	0.384 ± 0.000	0.358 ± 0.009	l	0.371 ± 0.004	uv	46
S007	0.439 ± 0.000	0.283 ± 0.033	m	0.361 ± 0.016	v	47
S12	0.424 ± 0.000	0.281 ± 0.013	m	0.353 ± 0.006	vw	48
S21	0.242 ± 0.000	0.410 ± 0.012	kl	0.326 ± 0.006	w	49
S45	0.401 ± 0.000	0.231 ± 0.011	m	0.315 ± 0.005	w	50
S28	0.292 ± 0.000	0.231 ± 0.017	m	0.261 ± 0.008	x	51
S11	0.236 ± 0.000	0.205 ± 0.003	m	0.221 ± 0.001	xy	52
300129	0.385 ± 0.000	0.000 ± 0.000	o	0.192 ± 0.000	y	53
S10	0.263 ± 0.000	0.102 ± 0.001	n	0.183 ± 0.001	y	54
S27	0.000 ± 0.000	0.346 ± 0.182	m	0.173 ± 0.091	y	55

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/horticulturae10070761/s1, Table S1: Aaccession information; Table S2: Extreme temperature and rainfall in Nanjing during the experimental process; Figure S1: The performance of six accessions with extreme cold tolerance and cold sensitivity.

References

1. Rhaetia, R.A.; Revathy, K.; Priya, M.M.; Shankar, S.R. Nutritive and proximate analysis on five weedy grasses for their potential use as fodder. AgroLife Sci.; 2020; 9, pp. 26-34. Available online: http://agrolifejournal.usamv.ro/index.php/agrolife/article/view/258 (accessed on 18 June 2024).

2. Cai, X.; Trenholm, L.E.; Kruse, J.; Sartain, J.B. Response of ‘Captiva’St. Augustinegrass to Shade and Potassium. HortScience; 2011; 46, pp. 1400-1403. [DOI: https://dx.doi.org/10.21273/HORTSCI.46.10.1400]

3. Wherley, B.; Chandra, A.; Genovesi, A.; Kearns, M.; Pepper, T.; Thomas, J. Developmental Response of St. Augustinegrass Cultivars and Experimental Lines in Moderate and Heavy Shade. HortScience; 2013; 48, pp. 1047-1051. [DOI: https://dx.doi.org/10.21273/HORTSCI.48.8.1047]

4. Li, R.; Qu, R.; Bruneau, A.H.; Livingston, D.P. Selection for Freezing Tolerance in St. Augustinegrass through Somaclonal Variation and Germplasm Evaluation. Plant Breed.; 2010; 129, pp. 417-421. [DOI: https://dx.doi.org/10.1111/j.1439-0523.2009.01743.x]

5. Kimball, J.A.; Tuong, T.D.; Arellano, C.; Iii, D.P.L.; Milla-Lewis, S.R. Assessing Freeze-Tolerance in St. Augustinegrass: Temperature Response and Evaluation Methods. Euphytica; 2017; 213, 110. [DOI: https://dx.doi.org/10.1007/s10681-017-1899-z]

6. Moseley, D.O.; Trappe, J.M.; Milla-Lewis, S.R.; Chandra, A.; Kenworthy, K.E.; Liu, W.; Patton, A.J. Characterizing the Growth and Winter Survival of Commercially Available and Experimental Genotypes of St. Augustinegrass. Crop Sci.; 2021; 61, pp. 3097-3109. [DOI: https://dx.doi.org/10.1002/csc2.20445]

7. Li, Z.; Li, X.; He, F. Non-Structural Carbohydrates Contributed to Cold Tolerance and Regeneration of Medicago sativa L. Planta; 2023; 257, 116. [DOI: https://dx.doi.org/10.1007/s00425-023-04154-8] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/37171508]

8. Rimi, F.; Macolino, S.; Richardson, M.D.; Karcher, D.E.; Leinauer, B. Influence of Three Nitrogen Fertilization Schedules on Bermudagrass and Seashore Paspalum: I. Spring Green-up and Fall Color Retention. Crop Sci.; 2013; 53, pp. 1161-1167. [DOI: https://dx.doi.org/10.2135/cropsci2012.09.0562]

9. Schiavon, M.; Leinauer, B.; Sevastionova, E.; Serena, M.; Maier, B. Warm-season Turfgrass Quality, Spring Green-up, and Fall Color Retention under Drip Irrigation. Appl. Turfgrass Sci.; 2011; 8, pp. 1-9. [DOI: https://dx.doi.org/10.1094/ATS-2011-0422-01-RS]

10. Dunne, J.C.; Tuong, T.D.; Livingston, D.P.; Reynolds, W.C.; Milla-Lewis, S.R. Field and Laboratory Evaluation of Bermudagrass Germplasm for Cold Hardiness and Freezing Tolerance. Crop Sci.; 2019; 59, pp. 392-399. [DOI: https://dx.doi.org/10.2135/cropsci2017.11.0667]

11. Hinton, J.D.; Livingston, D.P.; Miller, G.L.; Peacock, C.H.; Tuong, T. Freeze Tolerance of Nine Zoysiagrass Cultivars Using Natural Cold Acclimation and Freeze Chambers. HortScience; 2012; 47, pp. 112-115. [DOI: https://dx.doi.org/10.21273/HORTSCI.47.1.112]

12. Gopinath, L.; Moss, J.Q.; Wu, Y. Quantifying Freeze Tolerance of Hybrid Bermudagrasses Adapted for Golf Course Putting Greens. HortScience; 2021; 56, pp. 478-480. [DOI: https://dx.doi.org/10.21273/HORTSCI15606-20]

13. Ebdon, J.S.; Gagne, R.A.; Manley, R.C. Comparative Cold Tolerance in Diverse Turf Quality Genotypes of Perennial Ryegrass. HortScience; 2002; 37, pp. 826-830. [DOI: https://dx.doi.org/10.21273/HORTSCI.37.5.826]

14. Maier, F.P.; Lang, N.S.; Fry, J.D. Evaluation of an Electrolyte Leakage Technique to Predict St. Augustinegrass Freezing Tolerance. HortScience; 1994; 29, pp. 316-318. [DOI: https://dx.doi.org/10.21273/HORTSCI.29.4.316]

15. Fry, J.; Lang, N.S.; Clifton, R.G.P.; Maier, F.P. Freezing Tolerance and Carbohydrate Content of Low-temperature-acclimated and Nonacclimated Centipedegrass. Crop Sci.; 1993; 33, pp. 1051-1055. [DOI: https://dx.doi.org/10.2135/cropsci1993.0011183X003300050035x]

16. Cardona, C.A.; Duncan, R.R.; Lindstrom, O. Low Temperature Tolerance Assessment in Paspalum. Crop Sci.; 1997; 37, pp. 1283-1291. [DOI: https://dx.doi.org/10.2135/cropsci1997.0011183X003700040043x]

17. Milla-Lewis, S.R.; Kimball, J.A.; Claure, T.E.; Tuong, T.D.; Arellano, C.; Livingston, D.P., III. Freezing Tolerance and the Histology of Recovering Nodes in St. Augustinegrass. Intl. Turfgrass Soc. J.; 2013; 12, pp. 523-530.

18. Maier, F.P.; Lang, N.S.; Fry, J.D. Freezing Tolerance of Three St. Augustinegrass Cultivars as Affected by Stolon Carbohydrate and Water Content. J. Am. Soc. Hortic. Sci.; 1994; 119, pp. 473-476. [DOI: https://dx.doi.org/10.21273/JASHS.119.3.473]

19. Kimball, J.A.; Tuong, T.D.; Arellano, C.; Livingston, D.P.; Milla-Lewis, S.R. Linkage Analysis and Identification of Quantitative Trait Loci Associated with Freeze Tolerance and Turf Quality Traits in St. Augustinegrass. Mol. Breed.; 2018; 38, 67. [DOI: https://dx.doi.org/10.1007/s11032-018-0817-y]

20. Kimball, J.A.; Isleib, T.G.; Reynolds, W.C.; Zuleta, M.C.; Milla-Lewis, S.R. Combining Ability for Winter Survival and Turf Quality Traits in St. Augustinegrass. HortScience; 2016; 51, pp. 810-815. [DOI: https://dx.doi.org/10.21273/HORTSCI.51.7.810]

21. Webster, D.E.; Ebdon, J.S. Effects of Nitrogen and Potassium Fertilization on Perennial Ryegrass Cold Tolerance during Deacclimation in Late Winter and Early Spring. HortScience; 2005; 40, pp. 842-849. [DOI: https://dx.doi.org/10.21273/HORTSCI.40.3.842]

22. Fry, J.D.; Lang, N.S.; Clifton, R.G.P. Freezing Resistance and Carbohydrate Composition of ‘Floratam’ St. Augustinegrass. HortScience; 1991; 26, pp. 1537-1539. [DOI: https://dx.doi.org/10.21273/HORTSCI.26.12.1537]

23. Luo, Y.; Zhang, X.; Xu, J.; Zheng, Y.; Pu, S.; Duan, Z.; Li, Z.; Liu, G.; Chen, J.; Wang, Z. Phenotypic and Molecular Marker Analysis Uncovers the Genetic Diversity of the Grass Stenotaphrum Secundatum. BMC Genet.; 2020; 21, 86. [DOI: https://dx.doi.org/10.1186/s12863-020-00892-w] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/32787786]

24. Song, Y.-B.; Yu, F.-H.; Li, J.-M.; Keser, L.H.; Fischer, M.; Dong, M.; Van Kleunen, M. Plant Invasiveness Is Not Linked to the Capacity of Regeneration from Small Fragments: An Experimental Test with 39 Stoloniferous Species. Biol. Invasions; 2013; 15, pp. 1367-1376. [DOI: https://dx.doi.org/10.1007/s10530-012-0374-y]

25. Li, Q.; Nothnagel, E.A. Absence of Variable Fluorescence from Guard Cell Chloroplasts of Stenotaphrum Secundatum. Plant Physiol.; 1988; 86, pp. 429-434. [DOI: https://dx.doi.org/10.1104/pp.86.2.429] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/16665925]

26. Liu, T.; Chen, D.; Liu, Z.; Wang, Z.Y.; Hu, J.S. First Report of Pyricularia Leaf Spot on St. Augustine Grass (Stenotaphrum secundatum) in China. Plant Dis.; 2018; 102, 1666. [DOI: https://dx.doi.org/10.1094/PDIS-11-17-1837-PDN]

27. Mei, S.S.; Wang, Z.Y.; Zhang, J.; Rong, W. First Report of Leaf Blight on Stenotaphrum Secundatum Caused by Nigrospora Osmanthi in China. Plant Dis.; 2019; 103, 1783. [DOI: https://dx.doi.org/10.1094/PDIS-02-19-0270-PDN]

28. Zong, J.; Li, L.; Yao, X.; Chen, J.; Wang, H.; Zhao, X.; Liu, J. Performance of Five Typical Warm-season Turfgrasses and Their Influence on Soil Bacterial Community under a Simulated Tropical Coral Island Environment. Land Degrad. Dev.; 2021; 32, pp. 3920-3929. [DOI: https://dx.doi.org/10.1002/ldr.4012]

29. Wu, Y.; Liao, L.; Wang, Z.; He, L. The Complete Plastid Genome of Stenotaphrum Subulatum Trin. (Panicoideae) and Phylogenetic Analysis. Mitochondrial DNA Part B; 2020; 5, pp. 1378-1380. [DOI: https://dx.doi.org/10.1080/23802359.2020.1735959]

30. Wang, Z.; Raymer, P.; Chen, Z. Isolation and Characterization of Microsatellite Markers for Stenotaphrum Trin. Using 454 Sequencing Technology. HortScience; 2017; 52, pp. 16-19. [DOI: https://dx.doi.org/10.21273/HORTSCI10521-16]

31. Reeves, S.A.; McBee, G.G. Nutritional Influences on Cold Hardiness of St. Augustinegrass (Stenotaphrum Secundatum) ¹. Agron. J.; 1972; 64, pp. 447-450. [DOI: https://dx.doi.org/10.2134/agronj1972.00021962006400040011x]

32. Karcher, D.E.; Richardson, M.D. Quantifying Turfgrass Color Using Digital Image Analysis. Crop Sci.; 2003; 43, pp. 943-951. [DOI: https://dx.doi.org/10.2135/cropsci2003.9430]

33. Richardson, M.D.; Karcher, D.E.; Purcell, L.C. Quantifying Turfgrass Cover Using Digital Image Analysis. Crop Sci.; 2001; 41, pp. 1884-1888. [DOI: https://dx.doi.org/10.2135/cropsci2001.1884]

34. Morri, K.N.; Shearman, R.C. NTEP Turfgrass Evaluation Guidelines. National Turfgrass Evaluation Program. 2014; Available online: https://www.Ntep.Org/Pdf/Ratings.Pdf (accessed on 18 June 2024).

35. Bunderson, L.D.; Johnson, P.G.; Kopp, K.L.; Dyke, A.V. Tools for Evaluating Native Grasses as Low Maintenance Turf. HortTechnology; 2009; 19, pp. 626-632. [DOI: https://dx.doi.org/10.21273/HORTTECH.19.3.626]

36. Russell, T.R.; Karcher, D.E.; Richardson, M.D. Daily Light Integral Requirements of Warm-season Turfgrasses for Golf Course Fairways and Investigating in Situ Evaluation Methodology. Crop Sci.; 2020; 60, pp. 3301-3313. [DOI: https://dx.doi.org/10.1002/csc2.20234]

37. Gu, S. Lethal Temperature Coefficient–a New Parameter for Interpretation of Cold Hardiness. J. Hortic. Sci. Biotechnol.; 1999; 74, pp. 53-59. [DOI: https://dx.doi.org/10.1080/14620316.1999.11511071]

38. Dunn, J.H.; Bughrara, S.S.; Warmund, M.R.; Fresenburg, B.F. Low Temperature Tolerance of Zoysiagrasses. HortScience; 1999; 34, pp. 96-99. [DOI: https://dx.doi.org/10.21273/HORTSCI.34.1.96]

39. Wang, H.; Cheng, X.; Shi, Q.; Xu, J.; Chen, D.; Luo, C.; Liu, H.; Cao, L.; Huang, C. Cold Tolerance Identification of Nine Rosa L. Materials and Expression Patterns of Genes Related to Cold Tolerance in Rosa hybrida. Front. Plant Sci.; 2023; 14, 1209134. [DOI: https://dx.doi.org/10.3389/fpls.2023.1209134]

40. Jin, D.; Xu, Y.; Gui, H.; Zhang, H.; Dong, Q.; Sikder, R.K.; Wang, X.; Yang, G.; Song, M. Evaluation of Cotton (Gossypium hirsutum L.) Leaf Abscission Sensitivity Triggered by Thidiazuron through Membership Function Value. Plants; 2020; 10, 49. [DOI: https://dx.doi.org/10.3390/plants10010049]

41. Singh, A.; Kumar, A.; Kumar, R.; Prakash, J.; Kumar, N.; Verma, A.K. Evaluation of Salt Tolerance in Jamun (Syzygium cumini L. Skeels) Using Morpho-Physiological Traits and Membership Function Analysis. Sci. Hortic.; 2024; 326, 112742. [DOI: https://dx.doi.org/10.1016/j.scienta.2023.112742]

42. Li, J.; Zhang, Z.; Chong, K.; Xu, Y. Chilling Tolerance in Rice: Past and Present. J. Plant Physiol.; 2022; 268, 153576. [DOI: https://dx.doi.org/10.1016/j.jplph.2021.153576] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/34875419]

43. Wingler, A. Comparison of Signaling Interactions Determining Annual and Perennial Plant Growth in Response to Low Temperature. Front. Plant Sci.; 2015; 5, 125650. [DOI: https://dx.doi.org/10.3389/fpls.2014.00794] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/25628637]

44. Zhang, Q.; Chen, Q.; Wang, S.; Hong, Y.; Wang, Z. Rice and Cold Stress: Methods for Its Evaluation and Summary of Cold Tolerance-Related Quantitative Trait Loci. Rice; 2014; 7, 24. [DOI: https://dx.doi.org/10.1186/s12284-014-0024-3] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/25279026]

45. Yang, X.; Brown, H.E.; Teixeira, E.I.; Moot, D.J. Development of a Lucerne Model in APSIM next Generation: 1 Phenology and Morphology of Genotypes with Different Fall Dormancies. Eur. J. Agron.; 2021; 130, 126372. [DOI: https://dx.doi.org/10.1016/j.eja.2021.126372]

46. Trischuk, R.G.; Schilling, B.S.; Low, N.H.; Gray, G.R.; Gusta, L.V. Cold Acclimation, de-Acclimation and Re-Acclimation of Spring Canola, Winter Canola and Winter Wheat: The Role of Carbohydrates, Cold-Induced Stress Proteins and Vernalization. Environ. Exp. Bot.; 2014; 106, pp. 156-163. [DOI: https://dx.doi.org/10.1016/j.envexpbot.2014.02.013]

47. Janská, A.; Maršík, P.; Zelenková, S.; Ovesná, J. Cold Stress and Acclimation—What Is Important for Metabolic Adjustment?. Plant Biol.; 2010; 12, pp. 395-405. [DOI: https://dx.doi.org/10.1111/j.1438-8677.2009.00299.x] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/20522175]

48. Dhont, C.; Castonguay, Y.; Avice, J.-C.; Chalifour, F.-P. VSP Accumulation and Cold-Inducible Gene Expression during Autumn Hardening and Overwintering of Alfalfa. J. Exp. Bot.; 2006; 57, pp. 2325-2337. [DOI: https://dx.doi.org/10.1093/jxb/erj204] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/16798845]

49. Luca, V.D.; de Barreda, D.G. Effect of a Biostimulant on Bermudagrass Fall Color Retention and Spring Green-Up. Agronomy; 2021; 11, 608. [DOI: https://dx.doi.org/10.3390/agronomy11030608]

50. Munshaw, G.C.; Ervin, E.H.; Beasley, J.S.; Shang, C.; Zhang, X.; Parrish, D.J. Effects of Late-season Ethephon Applications on Cold Tolerance Parameters of Four Bermudagrass Cultivars. Crop Sci.; 2010; 50, pp. 1022-1029. [DOI: https://dx.doi.org/10.2135/cropsci2008.09.0565]

51. Annicchiarico, P.; Collins, R.P.; Fornasier, F.; Rhodes, I. Variation in Cold Tolerance and Spring Growth among Italian White Clover Populations. Euphytica; 2001; 122, pp. 407-416. [DOI: https://dx.doi.org/10.1023/A:1012918100232]

52. Caturegli, L.; Ramazani, R.; Volterrani, M.; Grossi, N.; Magni, S.; Macolino, S.; Pornaro, C.; Bella, S.L.; Tuttolomondo, T.; Minelli, A. St. Augustinegrass Accessions Planted in Northern, Central and Southern Italy: Growth and Morphological Traits during Establishment. Ital. J. Agron.; 2018; 13, pp. 332-337. [DOI: https://dx.doi.org/10.4081/ija.2018.1294]