Nature and magnitude of genetic variability, heterosis and inbreeding depression in Amaranthus

Combining ability, heterosis and inbreeding depression were estimated in grain amaranths for ten characters. Non-additive genetic variance was predominant for majority of characters in both F1 and F2 generations. The parent AG-21 was good general combiner for yield/plant also showed high GCA effects for panicles/plant and harvest index in both F1 and F2 generations. Seven characters, the best F2s on the basis of SCA involves one parent with high GCA effect and the other with poor or average GCA effects. The hybrids which exhibited highest heterosis also showed high inbreeding depression. Heterosis over better parent was highest for economic grain yield (145.047%), followed by panicles/plant (113.675%), panicle length (33.656%) and grain weight/panicle (23.566%).