Seasonal variation in agronomic characteristics and sugar content of cabbage genotypes

ABSTRACT Cabbage is one of the most popular vegetables that is rich in sugars contributing to flavor and consumer acceptance; however, little information is available on the effect of genotypes and growing conditions on sugar accumulation. We assessed the seasonal variation in agronomic characteristics and free sugar content in cabbage (Brassica oleracea L. var. capitata L.) grown under open field conditions. Seventy-five cabbage genotypes were grown in the spring and autumn 2019, and their morphological characteristics and sugar concentrations were evaluated. Six cabbage types produced predominantly round-shaped heads (64 genotypes). Bright green and green were the dominant colors depending on the outer and inner leaves of the cabbage head. The most variable quantitative trait was head weight in both spring (36.9%) and autumn (49.2%). Glucose was the predominant sugar in most genotypes in both seasons. Mean glucose content in spring and autumn was 209.3 and 214.9 mg g-1 with 14.8% and 14.6% variation, respectively. Most genotypes produced higher fructose concentrations in fall than in spring. Sucrose levels showed the highest variation in both spring (36.0%) and autumn (60.5%), followed by fructose and glucose levels. Most agronomic parameters exhibited nonsignificant or negative correlations with sugar content, except the correlation of head height and width with glucose content. Fructose and glucose were positively correlated with total sugar content, while there was nonsignificant correlation with sucrose. Genotypes 160330 and 183701 produced comparably high and stable total sugar content in both seasons and can therefore be used as commercial breeding materials. We revealed a significant effect of genotype and season on cabbage agronomic characteristics and sugar content.