Abstract
A Japanese pear seedling population of fifteen families consisting of eight individuals per family and their parental cultivars was statistically analyzed with respect to fruit weight, flesh firmness, refractometer index and pH of juice.
Full-sib population analysis performed from 1963 to ′64 indicated that the ratio of variance component due to family to the total of variance was 0.078, 0.265, 0.046 and 0.066 for fruit weight, flesh firmness, refractometer index and pH, respectively.
From the analysis of the same hybrid seedling population and their parents, statistical significance was obtained in offspring-mid-parent regressions and correlation coefficients; the regressions were 1.152, 0.497, 0.644 and the correlation coefficients were 0.687, 0.560, 0.644 for flesh firmness, refractometer index and pH, respectively.
Both the ratio of variance component due to family to the total variance and offspring-mid-parent regression or correlation in the full-sib population are generally recognized as valuable parameters for estimating the heritability. Particularly the latter is generally considered more adequate.
From the results of the experiments, it is concluded that among the four characters flesh firmness has the highest heritability, followed by the refractometer index and the pH of juice, and fruit weight shows the lowest heritability.
