GENETIC-STUDIES OF 11 QUANTITATIVE CHARACTERS IN APRICOT

A comprehensive programme of apricot genetic improvement was started in 1969 at the INRA Fruit Research Station in Bordeaux. A half-diallel of the first generation, consisting of 15 F1 progenies and five S1 progenies, issued from six parents. Progeny means over 3 years were used for a genetic study. General combining ability (GCA) was highly correlated with the parental phenotype (r = 0.8-1 in ten out of the 11 characters studied) as was progeny mean with midparent value (r = 0.7-0.9 in nine out of the 11 characters). Heritability, estimated by regressing the progeny mean on midparental phenotype, was high except for fruit overcolour (h2 almost-equal-to 0.3); h2 ranged from 0.5 to 0.8 for seven characters and was greater than 0.9 for flowering date, maturity date and juiciness. The mean value of S1 progenies, as a function of the parental phenotype, did not differ from that of F1 progenies, but one progeny showed a poor yield which was ascribed to an inbreeding effect. The high correlations of GCA with parental phenotype, and of progenies with midparent, and some high or very high heritabilities indicated suitability of choosing parents based on their phenotype, and also the high potential for genetic improvement in the apricot.