Rooting performance of cassava cuttings due to the number of nodes and rooting media

Abstract

Cassava is a major food security crop in the developing world, providing a basic diet for over half a billion people. Stem cutting is the major propagation technique in commercial cassava production, despite its limitations in bulkiness and high cost. Research is lacking in optimizing the number of nodes for the most economical use of the planting material. It can be hypothesized that one or two node cuttings can be used in proper rooting media. Hence, a study was conducted to determine the appropriate number of nodes on selected rooting media for better rooting and shoot growth of cassava. A factorial combination of four number nodes (one, two, three, and standard, or 4–6 nodes) and four types of rooting media (sawdust, cocopeat, topsoil, and sand) was used in a completely randomized design with three replications. Nursery and field establishment data were collected. The result revealed that the interaction between the number of nodes and the media significantly (p < 0.05) affected all fresh and dry weights of root and shoot. Sawdust and cocopeat performed best in terms of root number, root length, leaf number, branch number, shoot length, and rooting percentage. Root fresh weight, root dry weight, shoot fresh weight, and shoot dry weight were higher when stem cuttings were planted using two or more nodes on cocopeat or sawdust as compared to planting them on topsoil or sand. The use of two or more nodes on cuttings using cocopeat or sawdust found outstanding results for rooting. However, the standard cutting was better for survival percentage during field establishment. The result confirmed that two nodes of cassava stem cutting are enough for the successful rooting of cassava, and sawdust promotes the rooting of cuttings. Hence, we recommend sawdust as a rooting medium and two or more nodes of stem cuttings of cassava.

INTRODUCTION

Cassava is among the most widely cultivated food crops in some districts of southern Ethiopia, mainly in the Wolaita zone (Legesse, 2018). The Qulle variety of cassava was introduced from Nigeria and is characterized by high returns, resistance to diseases, and low toxicity (Parmar et al., 2018). Its carbohydrate richness, availability throughout the year, tolerance to low soil fertility, and resistance to drought, pests, and diseases make cassava an attractive crop, especially to smallholder farmers, who account for the largest share of the country's agricultural production (Ewubare & Ologhadien, 2019; Inegbedion et al., 2020). Cassava can grow on poor soils, is easily propagated, requires little cultivation, and can tolerate periodic and extended periods of drought (Hillocks et al., 2002). The main part of the plant used for food is the tuberous roots, which can be retrieved from the soil up to 3 years after maturity (Lebot, 2009). This provides an important form of “insurance” against social disruption, prolonged droughts, or other periods of stress and unrest.

Seed is not the commercial propagation technique for cassava, and farmers do not establish it by using its seeds (Halsey et al., 2008). As stated by Lebot (2009), many cassava varieties have become adapted to vegetative propagation. As a result, the botanical seed is rarely used in commercial cassava cultivation. Cassava is, therefore, propagated vegetatively by stem cuttings (Ceballos et al., 2004). Stems older than 18 months are highly lignified and should not be used as planting material because their stems have fewer nutrient reserves, produce weak shoots, and have only a few storage roots (Bridgemohan & Bridgemohan, 2014). The use of stem cuttings from old plants makes cassava multiplication tedious and slow (Santana et al., 2009), leading to insufficient planting materials, which may restrict productivity. The planting materials from large cuttings are insufficient in number for large-scale plantations (Demeke et al., 2014). Shanker et al. (2019) and other scholars also reported that the rooting medium should be considered an integral part of the propagation system; percentage rooting and the quality of the roots produced are directly influenced by the medium. Mixtures such as perlite plus peat, coconut fiber, or vermiculite have also given good results (Fabbri et al., 2004). The type of rooting media and their characteristics are of greatest importance for the quality of rooted cuttings (Khayyat et al., 2007). Soil-less media have become very popular among propagators because of their consistency, excellent aeration, reproducibility, and low bulk density, which minimize the shipping and handling costs of the medium itself and the produced plants (Mamba & Wahome, 2010).

The rooting medium directly affects the quality and percentage of rooting (Farooq et al., 2018). According to Haile (2017), both the biological and physico-chemical characteristics of a potting medium affect plant and root growth. It is known that good growth media provide several essential functions, such as serving as a reservoir for plant nutrients, being suitable for gas exchange, anchoring the plant in place, maintaining available water, being well-drained, and being free of disease and insects (Galavi et al., 2013). Currently, traditional propagation of cassava using bulky stem cuttings is widely practiced around the world. This resulted in an increase in production costs and a scarcity of planting material. Lack of planting material is a serious problem for small-scale farmers, as is the propagation of new genotypes founded by cassava breeders. We hypothesize that the selection of an appropriate rooting medium for rooting can allow the use of a section or mini-stem with one or two nodes for the successful propagation of cassava for small-scale, resource-limited cassava growers and/or cassava breeders at the early stages of multiplication. Therefore, the current experiment was conducted to determine the optimum node number and appropriate media type for the successful propagation of cassava plants.

MATERIALS AND METHODS Description of the study area

The experiment was conducted at Hawassa University, College of Agriculture, which is located 273 km southwest of Addis Ababa in Sidama Regional State. The site is located at 7°03′05.7″ N and 38°30′21.1″ E, at an altitude of 1712 m above sea level. The average rainfall in the area is 800–1100 mm annually. The average annual maximum, minimum, and mean temperatures of the area are 27, 12, and 20°C, respectively. The main rainy season extends from April to September, and it is interrupted by some dry periods from May to July (NMA, 2015).

Nursery experiment Experimental materials, treatments, and design

For the experiment, cocopeat, sawdust, sand, and topsoil were used as rooting media. Cocopeat is a non-fibrous, spongy material obtained during husk extraction from coconut palms. It is imported by propagators for commercial use. Sawdust is a wood shaving (lignocellulosic compound) that mostly consists of cellulose (45%–50%), lignin (23%–30%), hemicellulose (20%–30%), and various extractives (acids, soluble sugar, resins, waxes, oil, etc.) (1.5%–5%) (Mohammed-Ziegler et al., 2004). Sand is a naturally occurring granular material composed of finely divided rock and mineral particles. It is characterized by its relatively high density and grain size.

The stem cuttings of cassava Qulle variety were used in this experiment. The variety is popular in Southern Ethiopia and adapted to wide environmental conditions. The experiment consists of four numbers of stem nodes (One bud, two buds, three buds, and standard [4–6 nodes]) in four different rooting media types (sand, topsoil, coco peat, and sawdust) laid out in a completely random design (CRD) in three replications. The experiment had a combination of 16 treatments in three replicates that gave a total of 48 experimental units. Each treatment combination was assigned randomly to the experimental units. A uniform rectangular small sunken bed size of 0.5 m by 0.5 m sunken bed was used for each treatment. The sunken beds were separated by 0.2 m from each other and covered with polyethylene sheets.

Experimental procedure

Cocopeat was obtained from commercial propagators (Nunhems Ethiopia PLC). Whereas both topsoil and sand were collected from the farm of Hawassa University's College of Agriculture demonstration field. Sawdust was collected from Hawassa University Enterprise. The experiment was conducted in a black plastic net house that allowed 50% light to pass in. Rectangular, sunken (15 cm deep) beds with a size of 0.5 m by 0.5 m were prepared inside the net house before the start of the experiment, and the ground of the beds was sealed with a polyethylene sheet. The different soil media were filled into the sunken beds, which were surfaced with polyethylene sheets. Mature and healthy-looking stem cuttings of cassava variety Qulle were collected from Bele (Wolaita zone). The stem pieces were prepared with different bud numbers according to the treatments. The stem piece with different node numbers was prepared and planted inside each medium, depending on the treatment combinations. Fifteen stem pieces were planted in each sunken bed as an experimental unit, for a total of 720 plants per entire experiment. Immediately after planting, the sunken beds planted with the stem pieces were covered in groups with a polyethylene sheet, making a hoop over the beds. This makes small polyethylene tunnels containing the sunken beds under them. The tunnel helps to maintain high relative humidity around the stem cuttings planted. The treatments (planted stem cuttings) inside the tunnel were checked for the need for water. Watering was done in the evening when the relative humidity dropped below 90%. After the stem cuttings were rooted, half of the rooted cuttings were transferred to the field to observe the survival rate. Another half of the rooted cuttings were left for measurements of the root and shoot parameters.

Data collection Nursery data

For the measurement of parameters, five rooted cuttings were randomly selected from each treatment combination per replicate 46 days after planting, and an average was calculated on a per-rooted cutting basis. The measurements were taken as presented in the following paragraph.

Root and shoot lengths were measured using a tape meter. The longest root was measured from each rooted cutting, and the height of the new growth on the stem cutting was measured for shoot length. Root and shoot numbers were counted for each selected rooted cutting. All emerged leaves were also counted from the cuttings to express the leaf number per cutting. The sprout number was recorded as the number of buds sprouted on the stem cuttings on the selected rooted cuttings. Fully extended branches were counted on each selected rooted cutting and recorded as the number of branches per rooted cutting. Immediately after uprooting rooted cuttings carefully, all roots and shoots that arose from the selected rooted cuttings were carefully removed and separately weighed using a sensitive balance to express root and shoot fresh weights. These fresh roots and shoots were oven-dried at 70°C for 48 h, and the dry weights of the root and shoot were measured using a sensitive balance. All the measurements were on a single plant/rooted cutting basis.

Data in field (during establishment)

Survival percentage: 2 months after field establishment, the number of surviving plants was counted and expressed as a percentage.

Data analysis

All collected data were subjected to the analysis of variance (ANOVA) following the procedure described by Gomez and Gomez (1984) using SAS software version 9.3. Treatments that show significant differences were subjected to the Least Significance Difference (LSD) for mean separation at the 5% probability level.

RESULTS AND DISCUSSION Nursery experiment

All parameters measured except shoot number were significantly affected by media type. Similarly, all parameters measured were affected by the number of nodes in the cuttings, except for root number and shoot length. The only significant interactions were observed for root fresh and dry weights and shoot fresh and dry weights (Table A1).

Root length, leaf number, branch number, and rooting percentage

The longest root length and highest branch number were recorded on stem cuttings with two and above numbers of nodes. The leaf number from stem cuttings with two nodes was even better than the standard cutting. The highest rooting percentage was obtained from the three and standard cuttings. Whereas the highest values of rooting percentage were recorded from three and the standard cuttings (Table 1). This might be due to the fact that longer cuttings tend to have longer roots since they accumulate more carbohydrates. Longer roots may be able to reach deeper soil. The results presented by Ky-Dembele et al. (2011) noted that higher rooting percentages observed from longer cuttings of the khaya plant may be related to better initial carbohydrate reserves stored in longer cuttings, which is consistent with the current finding regarding the numbers to rooting percentage. Other study by Adugna et al. (2015) also found that four nodal cuttings of guava planted on a 1:1:1 mixture of forest soil, decomposed animal manure, and fine sand rooting media had the largest number of leaves.

TABLE 1 Effect of rooting media and number of nodes on root length, leaf number, branch number, and rooting percentage.

	Root length (cm)	Leaf number	Branch number	Rooting (%)
Number of node
One	6.21b	19.14c	1.28b	27.23c
Two	9.06a	33.93a	2.74a	61.13b
Three	9.40a	27.32ab	3.04a	69.99ab
Standard (4–6)	11.05a	24.39bc	2.75a	79.43a
LSD (5%)	2.2	7.86	0.78	12.58
Rooting media
Coco peat	14.95a	35.96a	3.4a	76.68a
Sand	4.08c	15.83b	1.45b	46.10b
Sawdust	12.42b	36.36a	3.99a	80.57a
Topsoil	4.27c	26.65b	0.96b	34.42b
LSD (5%)	2.2	7.86	0.78	12.58

Note: Means followed by the same letters in the same column of each factor are not significant at the 5% level of significance.

Abbreviation: LSD, least significance difference.

With regard to rooting media, the longest root length (14.95 cm) was recorded from coco peat, and the lowest was obtained from sand and topsoil. While the highest leave number, branch number, and rooting percentage were obtained from coco peat and sawdust media (Table 1). This is due to the fact that coco peat and sawdust provide good retention of soil moisture and sufficiently available air space for the cuttings, favoring root initiation, growth, and shoot formation. Rooting media are an essential part of the propagation system because rooting competency depends on the type of medium used, which directly affects the quality and percentage of rooting (Lanyon et al., 2004). In line with the present findings, Fagge and Manga (2011) also declared that the quality of the rooting medium influences the root characteristics even before rooting because of the retention of water and aeration, which directly affect the quantity, length, and weight of healthy roots. In agreement with our findings, Kishan (2004) also observed the longest grape roots in both hardwood and semi-hardwood cuttings on sand +30% coco peat medium. According to Sameei et al. (2004), the maximum values of leaf area, leaf number, offset number, shoot and root fresh and dry weight, and shoot length in pothos were noted in mediums containing coco peat as rooting media.

Root number and shoot length

The average number of roots from cuttings varied with the type of media used. It ranged in average from 16.10 to 71.7. From the results, it was observed that the highest number of roots were obtained from cassava cutting grown both on coco peat (71.7) and sawdust (64.03) as no statistical differences between these two media types. A similar trend was also observed on shoot length, with better shoot length both on sawdust (8.96) and coco peat (7.63) as rooting media. Sand and topsoil were poor for the root number and shoot length growth (Table 2).

TABLE 2 Effect of the number of nodes of cassava cuttings and rooting media on root number and shoot length (cm)

	Root number	Shoot length (cm)
Number of nodes
One	5.45	29.20
Two	5.27	47.35
Three	5.14	41.50
Standard	6.10	50.40
LSD (5%)	NS	NS
Rooting media
Coco peat	71.70a	7.63a
Sand	16.50b	2.64b
Sawdust	64.03a	8.96a
Topsoil	16.10b	2.74b
LSD (5%)	17.6	1.51

Note: Means followed by the same letters in the same column of each factor are not significant at the 5% level of significance.

Abbreviation: LSD, least significance difference.

This result might be due to the fact that both sawdust and coco peat rooting media have better aeration and drainage of water, which could promote both root and shoot growth by fulfilling the required air space for the supply of sufficient oxygen for respiration. The spongy nature of the media and the availability of macro pores in abundance makes coco peat and sawdust suitable for rooting of cuttings. In accordance with our study, Maboko and Du-Plooy (2013) revealed that organic growing media (sawdust) has a favorable effect on plant growth. Marinou et al. (2013) also added that it increases the porosity and water retention of the plant-growing medium.

The current study was also supported by Farooq et al. (2018), who report that the media with canal silt (25%), bagasse (50%), and coco peat (25%) showed a significantly higher number of roots (50.00) in grape cuttings. Another worker, Kishan (2004), reported that the number of roots per cutting was greater in sand +20% coco peat on grape cuttings. The present result contradicts a study conducted by Sardoei (2014), who declared that sawdust was poor at rooting cuttings. The author explained that a mixture of sand and coco peat gave the highest values for the number of roots, average root length, and other root and shoot parameters of guava cuttings. Further studies showed that cuttings set in topsoil showed the lowest values for leaf width and number of roots on Vocanga africana cuttings (Ibrahim, 2016). From the results and reports, it can be seen that the rooting of cuttings was affected by the media type and the species of the plant.

Shoot number

Based on the current findings, a higher average number of shoots was observed in cuttings with three nodes and standard cuttings (4–6 nodes) (Table 3). Significantly, the lowest number of shoots were obtained from cassava cutting with one node (0.92) (Table 3). The present result is supported by Alikhani et al. (2011), who report that the highest and lowest shoot numbers were observed in multiple bud (2.73) and single bud (1.82) cuttings, respectively, on pomegranate cuttings.

TABLE 3 Effect of number of nodes and media type on shoot number of cassava cuttings.

	Shoot number
Number of node
One	0.92c
Two	1.39b
Three	1.67ab
Standard (4–6)	1.74a
LSD (5%)	0.31
Rooting media
Coco peat	1.51
Sand	1.25
Sawdust	1.53
Top soil	1.42
LSD (5%)	NS

Note: Means followed by the same letters in each factor are not significant at the 5% level of significance.

Abbreviation: LSD, least significance difference.

Root fresh weight

The result showed that stem cuttings with two nodes planted in coco peat and standard cuttings on sawdust had better root fresh weight (Table 4). Stem cuttings with one node, particularly those planted in sand or topsoil, resulted in lower root fresh weight (Table 4). This indicates that one node was not enough for rooting, particularly when using sand or topsoil as rooting media. The current result revealed that coco peat and sawdust resulted in better root fresh weight at different numbers of nodes in cuttings. This could be due to better aeration and good drainage of water, which could promote root growth and development. Air spaces are required for the supply of sufficient oxygen for respiration. The study conducted by Farooq et al. (2018) indicated that the fresh weight of roots per cutting was significantly affected by the potting medium. Results depict that the highest fresh weight of roots per cutting (2.16) was observed from the cuttings planted in mixtures of canal silt (25%) and bagasse (75%). They further concluded that combinations of canal silt (25%) and bagasse (75%), as well as combinations of canal silt (25%) + bagasse (50%) and coco peat (25%) potting medium, had produced the best results for the sprouting and growth of grape seedlings.

TABLE 4 Interaction effect of number of nodes of cassava cuttings and media on root fresh weight of rooted cuttings.

Rooting media	Number of nodes
	One	Two	Three	Standard (4–6)
Coco peat	0.67cde	6.03a	2.7bc	3.16b
Sand	0.05e	0.57cde	0.33de	1.40bcde
Sawdust	1.66bcde	2.59bcd	3.36b	6.09a
Topsoil	0.14e	3.00b	0.35de	0.67cde
LSD (5%)	2.3

Note: Means followed by the same letters are not significant at the 5% level of significance.

Abbreviation: LSD, least significance difference.

Root dry weight

The highest root dry weight (1.02) was registered from cassava stem cuttings with standard (4–6) cuttings grown on rooting media filled with sawdust (Table 5). Low root dry weight was obtained when cuttings with one node on all types of rooting media as well as when cuttings of all types were planted on sand or topsoil (Table 5). This shows that only one node of cutting, regardless of the media type, and sand and topsoil, regardless of the type of cuttings, were not suitable for rooting cassava cuttings. Topsoil and sand resulted in the lowest root dry weight, indicating the unsuitability of these media for rooting cassava (Table 5). Despite the differences, cuttings with two or more nodes planted in coco peat or sawdust resulted in better root dry weight, indicating sawdust can substitute coco peat for rooting medium. Cocopeat is not available for ordinary propagators, specifically for cassava farmers' usually small-scale and rural settings. Research by Burgess et al. (1990) reported that initial cutting size is important for improving the growth performance of Salix alba L. and is a very important factor involved in rooting ability and growth performance.

TABLE 5 Interaction effect of media and number of nodes of cassava cuttings on root dry weight.

Rooting media	Number of nodes
	One	Two	Three	Standard (4–6)
Coco peat	0.095ef	0.52bc	0.44bc	0.566b
Sand	0.014f	0.069ef	0.056ef	0.22de
Sawdust	0.205def	0.368cd	0.496bc	1.02a
Topsoil	0.057ef	0.131ef	0.072ef	0.103ef
LSD	0.197

Note: Means followed by the same letters are not significant at the 5% level of significance.

Abbreviation: LSD, least significance difference.

Shoot fresh weight

The highest and best shoot fresh weight was obtained from cassava cuttings grown on three nodes or standard (4–6) cuttings with sawdust as rooting media (Table 6). Cassava cuttings with three nodes or standard node numbers (4–6) grown on sawdust and three node cuttings grown on coco peat were statistically similar. One node cutting on cocopeat, sand, and topsoil, as well as all cuttings on sand and topsoil, resulted in poor shoot fresh weight (Table 6). This might be due to the fact that both cocopeat and sawdust had better aeration and water retention, resulting in longer roots that could have the ability to penetrate deeper and therefore have a greater capacity for water and nutrient absorption, leading to heavier shoot fresh weights in both media. Longer cutting with better-stored food on suitable media (coco peat and sawdust) resulted in better shoot growth.

TABLE 6 Interaction effect of rooting media and number of nodes on shoot fresh weight.

Rooting media	Number of nodes
	One	Two	Three	Standard (4–6)
Coco peat	4.54def	10.48cd	17.96ab	12.18bc
Sand	1.22f	3.87ef	2.69ef	2.53ef
Sawdust	7.96cde	13.80bc	20.73a	23.73a
Topsoil	3.48ef	2.88ef	3.2ef	2.57ef
LSD (5%)	6.56

Note: Means followed by the same letters are not significant at the 5% level of significance.

Abbreviation: LSD, least significance difference.

According to Adugna et al. (2015), the highest shoot fresh weight was observed from four nodal cuttings grown on a 1:1:1 mixture of forest soil, decomposed animal manure, and fine sand rooting media on vanilla cuttings. The result was also supported by Girma et al. (2012), who stated that the highest mean values were obtained from four nodal cuttings of vanilla. The current result contradicts the report by Sardoei (2014), who reported that the highest and lowest fresh weights were observed in sand and sawdust (2.33 and 0.51 g, respectively) on guava cuttings. The contradiction could be due to the inherited genetic differences between cassava and guava, the latter of which is difficult to root.

Shoot dry weight

Both the number of nodes and rooting media were the main factors, and the interaction of these two factors significantly affected the shoot dry weight of cassava-rooted cuttings (Table A1). Better shoot dry weights were recorded from cuttings with three nodes and standard cuttings planted in sawdust (Table 7). The result indicated that cocopeat and sawdust resulted in better shoot dry weight, particularly when cuttings with two or more nodes. In line with the current result, Vigl and Rewald (2014) indicated that stem cuttings with a larger diameter and longer length result in better survival and growth under normal conditions for Salicaceae cuttings. This might be due to the longer cutting, which accumulates more carbohydrates, which enables the seedlings to survive. Adugna et al. (2015) declare that the highest shoot dry weight was recorded from four- and five-node cuttings grown on a 1:1:1 mixture of forest soil, decomposed animal manure, and fine sand on vanilla.

TABLE 7 Interaction effect of media and number of nodes on shoot dry weight.

Rooting media	Number of nodes
	One	Two	Three	Standard (4–6)
Coco peat	0.52def	1.23cd	1.87bc	1.33cd
Sand	0.11f	0.56def	0.38ef	0.40ef
Sawdust	0.98de	1.92bc	2.45ab	3.00a
Top soil	0.33ef	0.67def	0.36ef	0.34ef
LSD (5%)	0.82

Note: Means followed by the same letters are not significant at the 5% level of significance.

Abbreviation: LSD, least significance difference.

Establishment Survival percentage

The number of nodes had a significant (p < 0.05) effect on the survival percentage (Table A1). However, rooting media, the interaction of rooting media, and number of nodes had a non-significant effect on the survival percentage of cuttings. The highest value of survival percentage (82.3) was from Standard (4–6) cutting. This might be because the standard (4–6) cutting has a higher bud number and more nutrition reserved in the cassava stem. The lowest survival percentage (26.6) was obtained from one node (Table 8). This might be due to a less reserved nutrient in the node. Similarly, Lahai et al. (1999) noted that longer cuttings produced a fast-growing canopy, and unlike many other crops, the foliage and storage roots of cassava grow simultaneously, resulting in competition for assimilation, dry matter production, and phasic development.

TABLE 8 Effect of number of nodes of cassava cuttings on survival percentage (%).

	Survival percentage (%)
Rooting media
Coco peat	52.1
Sand	57.3
Sawdust	52.6
Top soil	50.0
LSD (5%)	NS
Number of node
One	26.6c
Two	48.95b
Three	55.23b
Standard (4–6)	82.3a
LSD (5%)	19.34

Note: Means followed by the same letters in each factor are not significant at 5% level of significance.

Abbreviation: LSD, least significance difference.

The survival percentage during establishment was tested after the rooted cuttings transferred in the field. The season of the establishment, the conditions, and the weather during transplanting may exert adverse conditions to the serval of the rooted cuttings. Further, refining and sorting of the conditions affecting the survival in field conditions need to be assessed in future works.

CONCLUSION

Cassava is propagated using stem cuttings, which are usually bulky and scarce for farmers. The current study was initiated to optimize rapid cassava propagation using a small number of nodes on different rooting media to economically use stem cuttings. The study in the nursery revealed that the main effects of rooting media and node number significantly affected root length, leaf number, branch number, sprouting percentage, shoot fresh and dry weight, and root fresh and dry weight. Whereas, the interaction of the two factors significantly affected root fresh weight, root dry weight, shoot fresh weight, and shoot dry weight. The higher number of branches, number of leaves, and rooting percentage were obtained from sawdust and coco peat rooting media with stem cuttings containing two or more nodes. Cassava stem cuttings with two or more nodes planted in coco peat or sawdust resulted in better root numbers, fresh and dry weights of roots and shoots. As a media, coco peat and sawdust resulted in a similar effect in favoring the rooting of stem cuttings of cassava. This indicates that sawdust which is low cost, and easily available can substitute coco peat which is a commercial rooting media, imported from abroad. It can be concluded that two or more node stem cuttings planted in coco peat or sawdust produced better root and shoot growth of cassava. Hence, the use of sawdust as a rooting medium and two or more nodes per cutting are recommended for small-scale cassava growers.

ACKNOWLEDGMENTS

The authors gratefully acknowledge Nunhems Ethiopia PLC and Hawassa University Enterprise for providing cocopeat and sawdust, respectively.

FUNDING INFORMATION

No funding was received to support this research or manuscript.

CONFLICT OF INTEREST STATEMENT

The authors have stated explicitly that there are no conflicts of interest in connection with this article.

DATA AVAILABILITY STATEMENT

All data are available in the manuscript.

A APPENDIX

TABLE A1 Analysis of variance for root and nursery parameters.

Parameter	Media	Number of nodes	RM*NoN	Error
df	3	3	9	32
Root number	9570.5***	695.03ns	473.73ns	22.94
Root length	374.72***	48.55*	6.15ns	2.648499
Leaf number	1588.43***	456.33*	67.56ns	9.452862
Branch number	25.95***	7.63**	0.97ns	0.938303
Rooting percentage	6179.69***	6209.82***	240.3ns	15.12
Shoot length	129.24***	2.18 ns	4.2547083ns	1.812554
Shoot number	0.198ns	1.66578***	0.1077926ns	0.372289
Root fresh weight	24.9***	15.01**	5.604824*	1.382327
Root dry weight	0.584839***	0.29454***	0.079698**	0.118576
Shoot fresh weight	550.14***	112.87**	44.37*	3.946479
Shoot dry weight	7.91***	1.666989*	0.5591021*	0.491871
Survival (establishment) % (in the field)	126.66ns	5282.32***	123.435ns	23.13

Note: *, **, and ***, significant at p < 0.05, at p < 0.01 and at p < 0.001, respectively.

Abbreviations: df, degree of freedom; NoN, number of nodes; ns, non-significant; RM, rooting media.