Diallel Analysis of Traits Concerning Yield in Rice

Abstract

The diallel analysis was applied to F₁'s derived from crossings in all combinations without reciprocals among five varieties representing Hokkaido rice cultivars with different plant types. Additive gene action (a) predominated over dominance action (b) in the number of panicles per plant, the number of spikelets per panicle, the mean straw weight and culm lemgth. On the other hand, the mean square of the b item was large in panicle weight per plant, 100-kernel weight and grain length. A parent, Shiokari seems to have nearly complete recessive gene(s) which reduce grain length. Panicle weight per plant, which consist of the number of panicles per plant and some other components, did not satisfy the hypothesis of additive gene action. The four F₁ hybrids of Shiokari were superior to the othper F₁ hybrids and the five parents. The percentage of panicle weight to the total plant weight satisfied the hypothesis of additive gene action, though it is a compound character composed of many component characters. This character showed unidirectional positive dominance.