Combining Ability Analysis of Juvenile Period in Pear

Abstract

Combining ability for transmission of juvenile period duration was studied in a large pear breeding population. The 92 parents, consisting of cultivars and selections of Pyrus communis L. and its interspecific hybrids with P. pyrifolia (Burm.) Nakai and P. ussuriensis Maxim., as well as genotypes of P. calleryana Decne., were crossed in 298 combinations. General combining ability was highly significant and of much larger magnitude than specific combining ability, indicating that juvenile period length was under predominantly additive genetic control. Selection of parents based on their juvenile period or their combining ability constants is likely to result in significant reduction in mean juvenile period.