Abstract
This study analyzed the photosynthetic traits of 74 sugarcane varieties using PAM-2500 and SPAD instruments over three years. Our findings revealed significant variations in photosynthetic characteristics across different genotypes and ratoon years, highlighting the complex interplay between genotype and environmental factors. Notably, the heritability of these traits ranged from 0.70 to 0.86, underscoring a strong genetic influence. Through principal component analysis, we identified three critical aspects of photosynthesis: efficiency and light utilization, electron transfer and reaction center status, and chlorophyll content, collectively explaining 99.9% of the observed variance. The germplasms were categorized into three efficiency groups - High, Moderate, and Low - based on their photosynthetic performance. Importantly, germplasms with high photosynthetic efficiency correlated with increased stalk weight and sucrose content, suggesting potential targets for breeding programs. This study contributes to a deeper understanding of sugarcane photosynthetic dynamics and offers valuable insights for future genetic improvement and sustainable cultivation strategies.