Genetic studies of yield contributing traits in Amaranthus.

Genetical studies on grain yield and its contributing traits were made in a six parent complete diallel in the F1 and F2 generations of one of the most widely grown grain species of grain amaranths (Amaranthus hypochondriacus L.). Graphical analysis indicated that epistasis exists for 1,000-grain weight in the F1. Grain weight/panicle, yield/plant and harvest index indicated absence of non-allelic gene interaction. The harvest index in the F1 and F2 and grain weight/ panicle, 1,000-grain weight, yield/plant in the F2 appeared to be controlled by overdominance effects. Higher grain yield appeared to be associated with dominant genes. Both additive and non-additive gene effects were responsible for the genetic variation in the diallel population. However, dominance variance was more important than additive variance in grain yield/ plant and harvest index in the F1 and F2. For 1,000-grain weight additive genetic variance was more important in the F1 and non-additive in F2. There was overdominance of a consistent nature in the two analyses for harvest index in the F1 and F2, grain weight/ panicle, 1,000-grain weight and yield/plant in the F2 and partial dominance for 1,000-grain weight in the F1.