Genotypic and irrigation-driven variation in soluble carbohydrate and polyol profiles of pistachio (Pistacia vera L.) cultivars

This study analyzed soluble low molecular weight carbohydrates, polyols, and organic acids in eight pistachio ( Pistacia vera L.) cultivars grown in Spain and evaluated how irrigation and ground cover affect the widely cultivated ‘Kerman’ variety. Using gas chromatography–mass spectrometry, major sugars (sucrose, raffinose, glucose, fructose, maltose), minor saccharides (sorbitol, galactosyl-glycerol), inositols ( myo -inositol, galactinol), and organic acids (fumaric, shikimic) were identified. Sucrose was the dominant sugar (3,704–4,688 mg/100 g) across cultivars, while raffinose and galactinol were particularly abundant in ‘Larnaka’, ‘Kerman’, and ‘Avdat’. To the best of our knowledge, sorbitol, myo -inositol, galactosyl glycerol, and galactinol have been detected in pistachio kernels for the first time. In ‘Kerman’, moderate deficit irrigation increased sucrose and raffinose, whereas severe deficit reduced overall carbohydrate levels; ground cover mitigated sugar losses and modified sugar distribution. Principal Component Analysis revealed clear cultivar discrimination driven by carbohydrate composition, with early-maturing genotypes tending to cluster together and showing higher associations with raffinose family oligosaccharides, while other cultivars were associated with soluble sugars, disaccharides, and polyols. Irrigation treatments were also separated, with deficit irrigation associated with reduced carbohydrate levels and greater variability. Overall, kernel carbohydrate composition is strongly influenced by genotype, water availability, and soil management. These findings provide insights for breeding and cultivation strategies aimed at improving water efficiency, nutritional quality, functional traits, and stress resilience in Mediterranean pistachio production.