Estimation of components variation, genotypic and phenotypic correlation coefficients of grain yield and its component in bread wheat (Tritium aestivum L.) under rainfed conditions

This study was conducted to estimate of narrow sense heritability of grain yield and its component, genetic and phenotypic correlation between these traits and yield. Two parent, Sardari and SON 64, with 50 F3 generations resulted of cross between them were planted in RCBD design in three replication. For measurement of these traits sampling was carried out before and after harvest. Estimation of genetic parameters was conducted considering the importance of genetic variation between and within generations. The maximum narrow sense heritability was detected for harvest index (h2n = %76.4) and the minimum narrow sense heritability was found for number of tiller (h2n = %5.9). The estimated value of narrow-sense heritability for grain yield was % 64.4. The additive effect was more important than number of grain per spike, 1000 grain weight, grain yield, biomass, and harvest index. Dominants effect was also more important than additive effects for number of tiller and length of awn. Yield had positive genetic correlation with seed in spike, number of tiller and biomass and negative correlation with length of awn and harvest index. Therefore, selection based on yield biomass and number of seed in spike due to high narrow sense heritability and genetic correlation with yield can supply favorable genetic gain. Finally, based on our results, we suggest that for increasing in seed yield of wheat under rainfed conditions, these latter two traits for indirect selection can be useful.