Proline Accumulation and Drought Tolerance in Green Gram (Vigna radiata L.)

Abstract

Green gram (Vigna radiata L.), a key legume crop in Asia, contributes to sustainable agriculture by fixing atmospheric nitrogen and providing valuable nutrients. Despite its importance, productivity is hindered by various factors including drought, affecting key physiological and biochemical processes, leading to reduced yields. This study aimed to identify drought-tolerant green gram genotypes by evaluating 50 accessions for root, shoot and biochemical parameters under controlled moisture stress. An increase in root length and diameter under stress was observed, which aids in nutrient uptake and osmoregulation. Conversely, shoot length and dry weight decreased due to moisture limitations, with genotypes like VBN 3 and PLM 38 showing resilience by maintaining higher dry weights. Biochemical analysis revealed that proline accumulation, which correlates positively with drought tolerance, increased in most genotypes, particularly in IC 395518 and ML 1415. This suggests its role in maintaining cell turgor and mitigating stress effects. Chlorophyll content decreased under stress, while total phenolic content increased in some genotypes, further indicating drought tolerance. Correlation and path analysis revealed strong positive relationships between root traits and proline content, emphasizing their importance in drought tolerance. The study concludes that genotypes with robust root systems and higher proline accumulation are more capable of withstanding drought, highlighting the need for breeding programs targeting these traits for improved green gram productivity under changing climates.