Application of secondary traits in barley for identification of drought tolerant genotypes in multi-environment trials

摘要

Discriminant function analysis (DFA) is a biometric method that can be used by breeders to distinguish between drought tolerant genotypes. Drought stress is one of the major limiting factors that reduce crop production in semi-arid and arid regions around the world. A multi-environment trial was conducted on barley to investigate various phonological and morphological characteristics under both drought stress and irrigated conditions. Ten indigenous barley genotypes were evaluated in four cropping seasons and in two locations of Iran. Genetic variation was observed in all traits. The traits observed in all genotypes were significantly different. The average broad sense heritability predicted for secondary traits (0.88) was significantly more than grain yield (0.62). The results could significantly discriminate between low and high yield genotypes under drought stress by describing eight secondary traits including biomass, spike weight, grain numbers per main spike, grain numbers per plant, awn length, days to flowering, grain filling period and potential yield. High yield genotypes were selected by discriminant analysis (Eq. (1)). The discriminant score (DS) could explain 67% of grain yield variations and had a significant correlation (r=0.82 ** ) with the average of grain yield examined under drought stress over four years. Consequently, integrated selection can be used as a reliable approach to future breeding programs. Results of DFA indicated that the most important traits, in order of appearance, are awn length, grain filling period, spike weight, and grain numbers per main spike. The results demonstrated that secondary traits could be considered as proper criteria to improve the genetic gain of grain yield and to select tolerant cultivars for environments that are susceptible to drought.