Effects of shading on morphology, photosynthetic characteristics, and yield of different Amorphophallus varieties.

Konjac (Amorphophallus spp.) is a typical shade-demanding cash crop, yet the adaptability of different varieties to light intensity remains poorly understood. This study used one Amorphophallus konjac variety (HMY01) and seven Amorphophallus bulbifer varieties (YunRe1701, YunRe1707, YunRe1709, YunRe1710, YunRe1726, XD09, and GY02) as materials, and established five light gradients (100%, 70%, 50%, 25%, and 7% of natural light) to systematically measure morphological, photosynthetic, and yield-related traits. The results showed that: (1) Moderate shading (25%-50% light) significantly promoted morphological growth, photosynthetic efficiency, and corm yield in most varieties, while both full light and 7% extreme low light inhibited growth and development, with significant differences in optimal light intensity among varieties. (2) Cluster analysis classified the eight varieties into three functional groups: HMY01 (high photosystem II (PSII) stability), morphology-dominant type (YunRe1701, XD09, GY02, emphasizing plant height and leaf area expansion), and photosynthesis-dominant type (YunRe1707, YunRe1709, YunRe1710, YunRe1726, emphasizing light energy use efficiency). (3) Principal component analysis (PCA) extracted four principal components with a cumulative contribution rate of 81.23%, effectively distinguishing two synergistic dimensions: 'light energy utilization and carbon assimilation' and 'morphological construction and pigment adjustment'. This study provides a scientific basis for variety selection and light management in konjac understory intercropping systems.