Study of genetic parameters and heterotic effects in crosses of maize (Zea mays L.) varieties with varying chromosome knob numbers

Abstract

Sibbed and selfed populations of ten maize varieties of geographically diverse origin and with chromosome knob number varying from 6–12, and their F1 crosses in all possible combinations were studied at two agro-climatically different locations to find out general and specific combining ability, gene action and hybrid vigour in the varietal crosses of maize. The general and specific combining ability and their interaction with locations were highly significant. The magnitude of variance due to interaction of locations with specific combining ability were much more than with general combining ability. The estimates for non-additive component were higher for yield per plant, plant height, and ear placement, whereas for days to silking, ear length, ear diameter and 100-grain weight, the additive as well as non-additive components were of the same order. The magnitude of heterosis over the better parent and the mid parent indicated absence of epistasis and prevalence of partial or complete dominance of genes for yield and days to flowering.