Multivariate Analysis of the Phenological Stages, Yield, Bioactive Components, and Antioxidant Capacity Effects in Two Mulberry Cultivars under Different Cultivation Modes

Mulberry fruits are rich in bioactive components renowned for their antioxidant properties and potential health benefits. This study thoroughly investigated the impact of cultivation modes on the phenological stages, yield, bioactive components, and antioxidant activity of two mulberry cultivars, Yueshen Dashi (YS-DS) and Xinjiang Baisang (XJ-BS). Notably, greenhouse cultivation led to earlier phenology and shorter fruit development maturation durations compared to field cultivation. Despite a decrease in fruit production and firmness, the greenhouse-grown mulberries exhibited higher individual fruit fresh weight. The content of bioactive components, encompassing anthocyanins, polyphenols, flavonoids, and vitamin C, and of antioxidant activity (measured in the FRAP and DPPH radical scavenging assays) was found to be lower in the greenhouse-grown mulberries than in those cultivated in the field. The contents of total polyphenols and flavonoids showed robust positive correlations in the FRAP and DPPH radical scavenging assays, which suggests that the antioxidant activity of mulberry fruit might be primarily attributable to the bioactive components of total polyphenols and flavonoids. Interestingly, the sugar content and hydroxyl radical scavenging activity (HRSA) displayed an inverse relationship between the two cultivars in the greenhouse versus field conditions. The multivariate analysis highlighted distinct patterns for different cultivars under varying cultivation modes. This study underscores the potential to enhance bioactive components and antioxidant activity through effective manipulation of climate conditions, thereby unlocking the full nutritional potential of mulberry fruits on a large scale in greenhouse environments.