Articles

Heterosis, Potence Ratio and Genetic Distance for yield and yield contributing traits in single cross maize hybrids


Abstract


The study is concerned with the development of single cross heterotic hybrids and to understand the underlying genetic principle for heterosis as well as to establish its relation with parental genetic divergence to formulate a breeding strategy for maize improvement. Heterosis was trait dependent exhibiting high level for plant height, cob characters and grain yield/plant. Two hybrids were better than standard checks, but only DMR QPM 103 x CML 539 recorded 26-28% heterosis over both checks and also displayed positive heterosis for cob characters as well for grain weight. Significanly it was almost seven days earlier in floweringwhich favoured pollination advantage with better floweringsynchrony. Cob characters were positively correlated with yield heterosis’s cob diameter was positively correlated with all cob characters. Cob diameter heterosis could be effective predictor for grain yield heterosis. Majority of the traits were controlled by over dominance gene effect, where more than 80% of hybrids recorded over dominance gene effect for plant height and cob characters. The breeding strategy has to be adopted to maximize heterosis. In this context it appears that inbred tester would improve the population more than the population tester because in an inbred, alleles are fixed whereas in population they are intermediate in frequency. As many as 34 hybrids recorded mid parent heterosis of 100% or above. Of them 25 (74%) belonged to the medium parental divergence group having parental grain yield of 50 g or above. It was observed that parents with high per se performance and intermediate genetic divergence produced highly heterotic and high yielding hybrids.

Keywords

Maize hybrids, Heterosis, Parental divergence, Potence ratio

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Maydica - A journal devoted to maize and allied species

ISSN: 2279-8013