Genetic Analysis of Grain Yield in a 7×7 Diallel Cross F_2 Population of Wheat（T.Aestivum L.）

In order to obtain genetic information for grain yield, seven genetically diverse wheat cultivars were crossed in an incomplete diallel to study the inheritance of grain yield using F2 progenies for two years. Significant differences were observed among genotype, year and genotype × year interaction for grain yield, and both general combining ability（GCA） and specific combining ability（SCA） were also highly significant for grain yield, suggesting that the trait was controlled by both additive and non-additive effect. The GCA estimates revealed that the best combiners for grain yield were Yangmai 5 and Ningmai 9. Adequacy tests revealed that data of grain yield was fully adequate for genetic interpretation. Over-dominance genetic effects were important for the expression of grain yield. Grain yield exhibited moderately high value of narrow sense heritability（hN2=66.98% and hN2=72.37%）.