Heritability of Juvenility in Peach

The feasibility of genetically curtailing the period of sexual repression in peach and nectarine seedlings was studied by assessing the propensity of 2-year-old seedlings in a dwarf peach and nectarine breeding stock to produce flowers and fruit. Mean flower number, in a breeding stock comprising about 6300 seedlings from about 300 families, was estimated to be 9 per 2-year-old seedling; with a narrow sense heritability 0.16 ± 0.02. Mean fruit number in this population was estimated to be 3.7 per 2-year-old seedling; with a heritability of 0.33 ± 0.03. It was estimated that 3 cycles of “mass selection” on this trait could increase mean fruit number to about 13 per 2-year-old seedling, thus facilitating a reduction in the minimum length of selection cycles in this breeding stock from 3 to 2 years.