Morpho-physiological and Biochemical Screening of Advanced Grass Pea Lines for Drought Stress Tolerance

Drought stress significantly affects the growth, physiology, and yield of leguminous crops like grass pea (Lathyrus sativus L.). This study evaluated the drought tolerance of five grass pea genotypes (GM-04, GM-02, GM-03, BARI Khesari-2, and BINA Khesari-2) under three water regimes: control, 60%, and 40% field capacity. Key physiological traits—chlorophyll content (SPAD), proline and soluble sugar levels, oxidative stress (MDA), and yield components were analyzed. GM-04 statistically outperformed other genotypes, maintaining higher SPAD values, increased proline and sugar accumulation, and lower MDA levels under stress, indicating effective osmotic adjustment and oxidative stress tolerance. It also achieved the highest yield under both moderate and severe drought, reflecting superior water-use efficiency. In contrast, BINA Khesari-2 showed poor drought response, with significant physiological damage and yield decline. These results suggest GM-04 as a promising drought-tolerant genotype suitable for cultivation in water-limited areas and valuable for breeding programs aimed at enhancing grass pea resilience to climate stress.