Genotypic and environmental effects on the concentration of bulb phytochemicals associated with garlic flavor, health-enhancing properties, and postharvest conservation

Abstract

To estimate genetic and environmental effects on traits associated with garlic functional value and postharvest quality, the content of total organosulfur compounds, phenolics, and solids were determined in selected garlic cultivars grown at four locations in Mendoza, Argentina. To this end, an initial experiment considered five cultivars grown in two locations and two years, and a second experiment evaluated 12 cultivars across four locations. Among all the cultivars and locations, pyruvate levels, an estimator of total organosulfur content, varied more than 4-folds (with a range of 24.7-111.1 μmol/g fw), phenolics varied ∼5-folds (132.1-703.1 mg gallic acid equivalents/kg fw), and solids varied within a range of 28.4-41.2%. Strong environmental influence and GxE interactions were found for all traits, together accounting for 54.8-63.2% of the variation found for pyruvate, 63.3-81% for phenolics, and 35.1-50.8% for solids. The impact of genotype was higher for solids (31.9-50.9% of total variation) than for pyruvate (33.6-40.4%) and phenolics (16.1-34.1%). Despite the substantial environmental influence and GxE interaction found, individual garlic cultivars with consistently high levels for all of these traits were identified. Garlic pyruvate, phenolic, and solids levels are genetically and environmentally-conditioned. The identification of environmentally-stable genotypes with high phytochemicals content are valuable for breeding programs aiming at increasing garlic flavor, functional value, and postharvest quality; whereas locations yielding contrastingly high or low pyruvate levels are of interest for producing pungent and mild garlics, respectively, to satisfy different markets and consumer preferences.