Heritability estimates in kiwifruit

Genetic studies were conducted in kiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson var. deliciosa] to estimate heritabilities of several important fruit characters. The objective was to test the repeatability of heritabilities estimated from annual data by comparison with combined seasons' data. Fruit characters were measured in two separate factorial mating designs over three consecutive seasons from 1996 to 1998. Heritabilities were estimated for 11 fruit characters based on data collected in each year and further analyses of the pooled years' data provided combined heritability estimates. Results showed low heritabilities (less than or equal to50.35) for yield, total fruit number, flavor and texture, and high heritabilities (greater than or equal to0.65) for mean fruit weight, fruit shape dimensions and soluble solids content. The annual heritability estimates were highly correlated with their respective combined years' estimates (r(2) = 0.97 to 0.99). We conclude that the data from any single year, from 1996 to 1998, were sufficient for estimating heritabilities for these characters. These results suggest genetic studies in kiwifruit could be effectively assessed early in the generation cycle without any significant loss of genetic information.