GENETIC VARIANCE-COMPONENTS AND HERITABILITIES OF SEVERAL AVOCADO TRAITS

Genetic variance components for avocado (Persea americana Mill.) trait s were estimated to improve avocado breeding efficiency. The additive and nonadditive genetic variance components were calculated from the v ariances between and within crosses. In all nine traits examined, i.e. -anise scent, fruit density, flowering intensity, fruit weight, harves t duration, inflorescence length, seed size, softening time, and tree size-a significant nonadditive genetic variance was detected. Additive genetic variance in all traits was lower and nonsignificant. The exis tence of major nonadditive variance was indicated also by narrow-sense and broad-sense heritability values estimated for each trait. Therefo re, parental selection should not be based solely on cultivar performa nce. Crosses between parents of medium and perhaps even low performanc e should also be included in the breeding program.