HERITABILITY OF SPRING BLOOM AND FALL LEAF ABSCISSION DATES IN PRUNUS-PERSICA

The heritability of fall leaf abscission and spring bloom date were estimated in a peach breeding stock recently infused with genes of divergent evolutionary origin. One of the two recent progenitors of this breeding stock was evergreen. The other had a high chilling requirement. The heritability of full-bloom date in this breeding stock was estimated to be 0.60 +/- 0.08 SD, under the assumption of no outcrossing, and 0.67 +/- 0.08 SD, under the assumption of 30% random mating. The heritability of the percentage of leaves abscised by 18 Nov. 1988 was estimated to be 0.33 +/- 0.08, under the assumption of no outcrossing, and 0.47 +/- 0.08, under the assumption of 30% random mating. The heritability of the percentage of leaves abscised, estimated from data collected on 14 Nov. 1989, was 0.49 +/- 0.08, under the assumption of no outcrossing, and 0.55 +/- 0.08, under the assumption of 30% random mating. The phenotypic correlation between date of full bloom and percentage of leaves abscised in the following November was estimated to be 0.21; 0.18 t(0.05) > 0.21 > 0.26 t(0.05). Apparently, these traits readily could be genetically manipulated to circumvent the freeze damage that leads to susceptibility to Cytospora and related disease organisms.