Association between grain yield and dry matter accumulation in Iranian wheat cultivars grown in Moghan region

The aim of this research was to study the association between dry matter accumulation (biological yield) and grain yield in Iranian wheat cultivars. The experiment was performed at Moghan College of Agriculture and Natural Resources research farm during 2010-2011 growing season. The plant materials (81 wheat cultivars) were evaluated using a simple lattice design with two replications under well-watered condition. Generally, modern wheat cultivars showed high values of grain yield when they compared with the old ones. This trend was also observed in the cases of harvest index (HI) and grain number per square meter. There were no significant differences in biological yield and thousand grain weight between old and new cultivars. Analysis of correlation showed significant and positive association between grain yield and biological yield which is not consistent with the lack of consistent increases in biological yield through breeding activity in the past. Is seems that modern wheat cultivars have lower amount of pre-anthesis dry matter accumulation than the old cultivars. But, they produce more photoassimilates after anthesis because of increased grain number. Therefore, albeit not significant increases in biological yield through breeding, the grain yield correlated positively with biological yield.