Heritability and Phenotypic Correlations in Peach

Ten peach [Prunus persica (L.) Batsch] horticultural and fruit quality traits were evaluated for two years at Fowler, CA and two years at College Station, TX to estimate heritability and phenotypic correlations. Seedlings from nine F₁ families along with parents used in crosses, were budded onto ‘Nemaguard’ rootstocks for evaluation. An all random effects model (REML) was used to estimate variance components and a multivariate model was used to estimate phenotypic correlations between traits. Moderate heritability (h² = 0.38 – 0.55) was estimated for bloom date, fruit blush, fruit diameter, fruit tip, fruit shape, and fruit ground color, while ripe date, fruit development period (FDP), fruit weight, and soluble solids showed low narrow sense heritability (h² = 0.06-0.24). These traits with low narrow sense heritability had moderate to high broad sense (H²) heritability, indicating an important non-additive genetic component. Two major genes had an effect on additive heritability. The pantao shape and nectarine had pleiotropic effects on fruit diameter, resulting in a higher estimate for this trait. Several traits (fruit blush, fruit weight, fruit diameter, fruit tip, fruit shape, fruit ground color, and soluble solids) were strongly affected by genotype by environmental interaction. Most traits exhibited substantial variability, which should allow for genetic improvement. Ripening date was strongly correlated (r = 0.92) with FDP, while bloom date was negatively correlated with FDP (r = -0.44) and fruit tip (r = -0.40). Ripening date and FDP were moderately correlated with fruit weight (r = 0.54, r = 0.50) and fruit diameter (r = 0.55, r = 0.51). Both measures of fruit size were strongly correlated (r = 0.83).