Heritability and correlation studies of certain quantitative traits in table grapes, <i>Vitis</i> spp.

Abstract

Heritabilities and phenotypic correlations among 10 traits of the grapevine (Vitis vinifera x V. rotundifolia hybrid derivatives) were estimated from measurements obtained from 46 families, induding a total of more than 1000 offspring generated by crosses among 26 parents. Measurements on fruit characters were obtained over a period of 4 years, 1976-1979. (General vigor of the vines was measured in only 1 year, 1976). Prior to this analysis the data on fruit traits were statistically adjusted to mitigate the confounding effects of fluctuating annual dimates on estimates of genotypic value. The heritabilities were then estimated by regressing the average performance of each seedling on the average performance of its mid-parent. Heritabilities are 0.12, 0.55, 0.49, 0.75, 1.04, 0.34, 0.15 and 0.10 for duster weight, duster compactness, berry weight, skin texture, pulp texture, total soluble solids, acidity of juice and general vigor, respectively. The heritability estimate for crop weight in this population is practically 0(-0.08). The precision of these estimates is very high, except for that of general vigor. Thus, they should be reliable predictors of the rate of genetic gain attainable in such populations when seedlings are selected as parents on the basis of their own performance. The expected performance of the progeny of randomly mated parents, ranked in the upper 5 % of the progeny generation, were estimated. The implications of these genetic relationships on the effectiveness and efficiency of breeding programs and selection procedures in grapes are discussed.