Evaluation the relationships between grain yield and some of its related traits in a doubled-haploid bread wheat population

With increasing the world population, and needing to feed it, the yield enhancement of cereals crops is of the most important approaches meet this target, which is achieved via identifying the effective factors underlay yield of cereals like wheat. This experiment was conducted to evaluate the grain yield and its association with some contributed traits in a doubled-haploid (DH) wheat population comprising 100 DH lines deriving from across with maize, along with their parents (CK1 & ES32) and 6 Iranian local cultivars. Traits under study were of grain yield per unit area, number of fertile tiller and total number of tillers per plant, number of node, plant height, flag leaf length and width, spike length, number of grains per spike and 100-grain weight. The results indicated significant (P<0.01) correlations between grain yield with grain number per spike, spike length, and flag leaf length and width. According to stepwise regression analysis: spike length, number of tiller, flag leaf length, and number of grains per spike were the most important causing traits mostly (73%) interpreting the grain yield variation. The simple path coefficients analysis revealed that spike length and number of grains per spike contributed the most significantly (P<0.01) direct effects on grain yield. Moreover, the sequential path analysis showed that the number of tiller had a significant (P<0.01) positive direct effect on grain yield. In addition, there was significant direct effect of grain number on 100-grain weight and of spike length effect on number of grain per spike. Orthogonal contrast analyses results indicated also a nonsignificant difference between local cultivars and DH lines for the most important economic trait, yield. The results of this research could be applied for select the important yield contributed characters as selection criteria according to homogeneity of DH lines, and pave the way to potentially increase the yield of bread wheat cultivars.