The expected proportion of individuals in progeny having genotypic values for fruit weight over a given selection criterion to the total individuals derived from a cross was estimated by multiple-regression analysis in which inbreeding coefficient (F) and midparental (MP) value were independent variables and progeny mean was the dependent variable in Japanese persimmon (Diospyros kaki Thunb.). A total of 117 seedlings from 39 crosses was used. Genetic differences of progenies among crosses could be explained solely by F and MP, the effect of the former being greater than the latter. The expected proportion of progenies with large fruit decreased as MP decreased and severely decreased as F increased. Based on the parental mean of 35 fruit on a single tree for 3 years, the proportion of individuals in progeny with fruit weight >200 g was estimated as 34%, 21%, and 12% for 0, 0.125, and 0.25 F values, respectively, in individual from a cross with MP = 200 g.
M. Yamada, H. Yamane and Y. Ukai
M. Yamada, H. Yamane, K. Yoshinaga and Y. Ukai
Genetic and environmental variances for fruit ripening time (FRT), fruit weight, and soluble solids concentration (SSC) in Japanese persimmon (Diospyros kaki Thunb.) were estimated. The variance among fruit within a tree was the largest among environmental variances. Therefore, using a large sample size per tree and per year effectively increased heritability, but the effect was minimal when more than five fruit were sampled. The variance among years was largest for SSC and smallest for FRT. Generally, the variance associated with the genotype × year interaction was as large as the tree × year interaction. The variance among trees within a genotype was negligible for all traits. Repeating measurements yearly was more efficient than replicating trees.