Lablab purpureus: Evaluation and Selection of Drought-tolerant - High-yielding Accessions in Dry Farming Systems Based on Drought Tolerance Indices and Multi-environmental Yield Trials

Knowledge of plant responses to the soil moisture regimes is pre-requisite for drought tolerance studies. The present research study was performed to evaluate drought tolerant indices for selection of Lablab genotypes able to tolerate early Terminal Moisture Stress (TMS). The three evaluation sites from different agro-ecological conditions were selected for this study. Each of the site consisted of two trials with moisture stress-free (MSF) and early TMS conditions. The designs of the experiments comprised of a randomized complete block design. The twelve accessions used in the study were the best genotypes selected from the former moisture screening experiment at the seedling stage. Data collections included seed yield plant-1 at MSF and TMS conditions. The responses of Lablab accessions to TMS conditions were quantified through ten developed indices whose correlation coefficients (significant* @ p=0.05, ** @ p=0.01 at 5%) were computed from the mean of the seed yield plant-1 under both conditions. Based on this analysis, three indices; MP, GMP, and STI were discovered with higher correlation coefficients (> 0.5), and effective for selecting the TMS tolerant accessions with high seed yield plant-1 under both conditions. TMS tolerant accessions were selected based on combined rank mean method of desirable indices at all the sites. Through the combined rank mean method, D147, D363, HA4, D349, D352, D348, and D359 were generally selected as TMS tolerant accessions with high seed yield plant-1 across the sites. We therefore, suggest farmers' evaluation of the above-selected accessions in their fields before releasing them as commercial varieties.