UC Davis

Abstract:

Understanding the intricate interplay between genetic, environmental, and management factors shaping kernel compositional traits in pistachio (Pistacia vera L.) is pivotal for enhancing crop quality. This study examines variation in genetic, environmental, and management factors underlying fat, protein, and moisture content across 24 diverse pistachio cultivars grown in 7 environments, and with some grown under different management conditions: a pruning trial with three treatment levels, and an irrigation trial with four. Development of a Near-Infrared Spectroscopy (NIRS) calibration tailored to pistachio could enable rapid assessment of kernel composition in breeding programs and in post-harvest quality control. Furthermore, when integrated with multi-environment field trials, the impacts of genotype, environment, and agronomic practices on kernel quality could be elucidated. Our findings indicate that NIRS-based predictions were successful in accurately determining total fat, protein, and moisture content (with r of 0.43, 0.93, and 0.70, respectively) in ground pistachio kernels. Total mean fat percent was 45.94%, protein was 21.28%, and moisture was 3.23%. Significant differences were detected between pistachio compositional traits across cultivars and locations (within harvest years), but not in their interaction effects. The elite cultivars Golden Hills and Lost Hills recorded higher average fat content than Kerman, which recorded higher average protein than those two cultivars. Additionally, samples from the 2022 harvest year had higher average fat and moisture percent than samples from the 2023 harvest year. Through the integration of spectral analytical approaches with genetic and multi-environment trials, this research provides an understanding of the complex interactions governing pistachio kernel composition. Findings from this study offer valuable insights for breeding programs and agronomic strategies aimed at optimizing pistachio quality in diverse agricultural contexts.