Evaluation of common bean entries for drought tolerance in Ethiopia

Soil moisture deficit is the main constraint to common bean production in Ethiopia, particularly in the low altitude regions where rainfall is erratic and often inadequate for optimum bean growth. To examine common bean entries (cultivars/entries) for drought tolerance, twenty entries from CIAT germplasm and other sources were tested at Melkassa Research Center (Ethiopia) under water stressed (late planting) and unstressed (early planting) environmental condition during 1888, 1989 and 1993, from late June to the middle of October. The highest yielding entriers were G 2816 and A 422 in the unstressed and stressed environments respectively. Five different drought stress indices were used to identify drought tolerant lines; including; the Arithmetic mean, Geometric mean response, Percent reduction, and Fisher and Maurer stress index. Lines A 422 and A 410 were identified as the most drought tolerant lines by these indices. Correlation analyses between the various indices and seed yield were conducted for data from the unstressed and stressed environments (Table 3) to determine effectiveness in selection for drought tolerance. The Fischer stress index and the geometric mean index and the strongest correlation with yield in the stressed environment. These results indicate that these indices would best identify drought tolerant lines in water deficit environments and are in agreement with the conclusions ot White and Singh (1991). Regression coefficients from stability analyses were not associated with yield performance in either environment. eng