Carpological Variability of Almond [Prunus dulcis (Mill.) D.A. Webb cv. Nonpareil] in a Single Orchard during Seven Consecutive Harvests

Abstract

A multiyear study was conducted in California's San Joaquin Valley to examine variability of carpological characteristics of the popular Nonpareil almond cultivar. Samples of ‘Nonpareil’ almond fruit were collected from a single orchard during seven consecutive harvests and evaluated for 19 specific carpological characters. Harvest year significantly affected all measured variables. Of the evaluated characters, fruit weight was the most variable between years, whereas kernel percentage was one of the least variable characters. As a result of year-to-year variability in carpological characters, the relationship between kernel weight and all other measured variables was investigated to determine if regression models could better describe kernels. Kernel weight best explained variability in kernel surface area (R2 = 0.943) with year-to-year variability having only a minor affect on the relationship. The results indicate that ‘Nonpareil’ almonds cannot be described using simple metrics and that definitive metrics must be able to account for differences among years.