Identification of effective morphological traits on rice cultivars yield under moisture stress condition using multivariate statistical methods

One of the main problems in rice cultivation and production is the lack of water resources, especially during periods of low rainfall which affect vegetative growth rate and the level of yield. Drought stress has been well documented as an effective parameter in decreasing crop production, and developing and releasing new varieties which are adapted to water deficit conditions can be a constructive approach to overcoming unsuitable environmental conditions. Hence, the characterization of genetic diversity and germplasm classification for parental selection in breeding purposes is of great importance.
In order to evaluate the adaptation of rice genotypes to drought stress and to identify tolerant and sensitive genotypes, 20 genotypes were studied using a factorial randomized complete block design with three replications at the Rice Research Institute (Rasht). During growth stages, some traits were recorded such as plant height, total and fertile tiller number, flag leaf area, panicle length, filled and empty grain number, 100-grain weight, number of days to maturity and yield.
Mean comparison showed that the lowest percentage changes in traits among local varieties (Hashemi, Alikazemi and Sangjo) and improved cultivars (Dorfak, Sepidrood and Shiroodi) respectively. Cluster analysis using Ward’s minimum variance and squared Euclidean distance for agronomic traits divided the genotypes into two groups. The separated varieties were grouped in clusters with high quality on the basis of morphological traits and this guides us to select the most different and the best for hybridization programmes, especially to hybridize with local varieties in order to create new varieties resistant to stress. The result of factor analysis based on the principal component showed that factors three and four accounted for 73- 85 of total variance.
For the selection of genotypes with high yield and stress tolerance in rice, total and fertile tillers, days to maturity, flag leaf area, panicle length and 100-grain weight could be considered through estimating suitable selection indices for these traits. local and improved cultivars. The study found that the different groups show genetic variation in rice genotypes.