Abstract
Magnitude of heterosis and estimates of additive (a), mean dominance (b1), additional dominance (b2) and residual dominance (b3) effects for four sucker-producing characteristics of tobacco were studied by using a diallel set of crosses excluding reciprocals among eight tobacco cultivars differing widely in sucker productivity. Tobacco plants were grown in randomized complete block field with two replications at the Utsunomiya Tobacco Experiment Station in 1980. Significant differences in sucker productivity were observed among eight cultivars and their 28 F1 hybrids. The heterotic response of the hybrids was toward lower sucker productivity. Diallel analysis of variance of the F1 hybrid generation and estimation of genetic parameters indicated that a large amount of variance was due to additive genetic effects and that small amount of variance was due to dominant genetic effects. These estimates suggest a predominance of additive genetic variance in the population for sucker productivity. Heritabilities of four characteristics, that is, the number and dry weight of ground suckers and the number and dry weight of upstalk suckers, were O.689, O.323, 0.414 and O.512, respectively, Correlations among four sucker-producing characteristics were significant.
