Genetic nature of high density grain and associated rice panicle characters
1988
Mallik, S. | Aguilar, A.M. | Vergara, B.S. (International Rice Research Inst., Los Banos, Laguna (Philippines). Plant Physiology Dept.)
One way of improving rice grain yield is to increase the number of high density (HD) grains (specific gravity 1.20) per panicle without increasing the number of spikelets. The nature of gene action was studied through mean analysis heterosis, heterobeltiosis, potence ratio, heritability, number of effective factor pairs and phenotypic correlation among traits in parents F1 and F2 in seven crosses. Most of the characters studied were governed by dominance effects. Both additive and dominance effects were important in the inheritance of spikelet number and HD grain index on secondary branches. Positive heterosis was observed for number of tillers, primary and secondary branches, sterility on secondary branches and inner vascular bundles. Heterosis was negative for the number of spikelets on tertiary branches, sterility on primary branches and outer vascular bundles. The broad sense heritability estimates were high to moderate for all the characters measured. The number of effective factor pairs did not exceed two for any trait. The relationship between any pair of characters differed among the generations. However, HD grain index on primary braches was significantly and positively correlated with the number of primary branches, spikelet on primary branches and HD grain index on secondary branches in all the generations indicating additive gene action.
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