Prediction of genotypic values for apple fruit texture traits in a breeding population derived from 'Honeycrisp'

The commercially successful apple (Malus pumila Mill.) cultivar Honeycrisp is known for its high degrees ofcrispness and juiciness. This cultivar has been incorporated into numerous breeding programs in an effort to duplicateits desirable texture traits in conjunction with such other traits as reduced postharvest disorders, disease resistance, andimproved tree vigor. This study characterizes variability and estimates heritability for several apple fruit texture traitswithin a large breeding population over several years. Five full-sib families, all sharing 'Honeycrisp' as a commonparent, were assayed with respect to crispness, firmness, and juiciness using sensory evaluation panels and total workrequired to fracture tissue using instrumentalmethods. The incomplete block design of the sensory panels, coupled withbest linear unbiased prediction, facilitated the evaluation of a large number of genotypes with small numbers of fruit pergenotype while accounting for individual sensory panelist effects.Broad-sense heritability estimates exceeded 0.70 for allfour traits. Principal component analysis, applied to the phenotypic data, characterized 'Honeycrisp' as having averagecrispness and low firmness (53rd percentile relative to its offspring) but also as being a relatively extreme example ofhigh juiciness and low work to fracture (first percentile). The improved characterization of desired fruit texturephenotypes and the high levels of broad-sense heritability provide valuable tools for the further development of new,high-quality apple cultivars.