Genetic variability of panicle architecture traits in different rice accessions under the Eastern Terai conditions of Nepal

Abstract

The panicle architecture is a critical determinant of the reproductive success of rice plants and has a direct impact on grain production. In this study, we evaluated the genetic variation of panicle parameters in fifteen rice genotypes and compared them with five commonly grown cultivars in the study area to assess their potential for crop improvement initiatives. The selection of the 15 genotypes was based on specific criteria, including diversity in origin, grain type, and adaptation to local conditions. Significant morphological variations were observed among the rice accessions for panicle parameters, including panicle length, weight, test weight, panicle number, grains/panicle, chaffs/panicle, and flag leaf area. Principal component analysis (PCA) revealed that the first two axes explained 59.8% of the total variance, indicating substantial variability in panicle features across the genotypes. Panicle length, panicle weight, and flag leaf area were identified as significant variables contributing to phenotypic variation. Multiple correlation analysis indicated that panicle weight was strongly positively correlated with panicle length, flagleaf area, grains/panicle, and test weight but was negatively correlated with panicle number, chaffs/panicle, and panicle angle. Genetic advance as a percentage of the mean (GAM) ranged from 7.226% for panicle number to 70.728% for chaffs/panicle. Traits such as grain/panicle, panicle length, flag leaf area, chaffs/panicle, and test weight exhibited high GAM and heritability, highlighting their significance for selection during crop improvement. Certain rice accessions, namely SVIN123, IR106523-25-34-3-2-13-1-2, Radha-13, and IR15L17315, demonstrated superior panicle weight, larger grains/panicle, and panicle length, making them attractive candidates for future rice breeding projects.