Effects of Light Quality and Photoperiod on Growth, Dry Matter Production and Yield of Ginger

We investigated the effects of light quality and photoperiod on the phenotypic characteristics, dry matter production, and yield of ginger under three light quality ratios (A1: blue light: white light = 1:4; A2: blue light: white light = 1:1; A3: pure white light) and two photoperiod conditions (B1: 12/12 h·d^-1; B2: 16/8 h·d^-1). The results demonstrated that blue light treatment significantly reduced plant height and the dry matter distribution ratio of stems and sheaths. In contrast, stem diameter, tiller number, leaf area, theoretical biomass (TBY), maximum accumulation rate (<i>V</i>_max), average accumulation rate (<i>V</i>_aver), time point of maximum accumulation (<i>T</i>_max), rapid growth period (DRGP), dry matter distribution ratio of leaves, roots, and rhizomes, number of rhizomes per plant, average rhizome weight, and yield all significantly increased with an increasing blue light ratio. Principal component analysis revealed distinct phenotypic traits, dry matter production characteristics, and yield-related traits under different blue light treatments. Blue light promoted tillering and increased stem thickness, which are key mechanisms for enhancing ginger yield. Additionally, prolonged photoperiods significantly increased plant height, stem diameter, branch number, leaf area, and biomass, while promoting the redistribution of photosynthetic products from leaves to rhizomes and increasing the proportion of dry matter allocated to rhizomes, thereby boosting ginger yield. These findings provide valuable insights into optimizing light conditions for ginger cultivation, highlighting the importance of a balanced blue-to-white light ratio and extended photoperiods in improving ginger growth and productivity.