Effect of Moderate Drought Stress on Photosynthetic Rate and Grain Yield in Finger Millet Genotypes

In the changing climate scenario, drought could be continued as a major abiotic limitation for crop productivity. Finger millet although known for its drought tolerance, the drought stress decreases the grain yield from 25 to 100 percent depending on the duration and magnitude of drought stress. Present study was conducted to explore the genetic variability of selected genotypes over the ruling varieties if any, based on the extent of reduction in grain yield, and dependent photosynthetic traits due to moderate drought stress for 18 to 20 days (grand growth to flower primordial initiation). Five selected genotypes were compared with three released varieties under field condition by withholding the irrigation for stress treatment. Moderate drought stress for a period of 18 to 20 days decreased the photosynthetic rates markedly due to decreased stomatal conductance and transpiration rates. However, yield reduction was less than 6.0 per cent in released varieties. Correlations and path analysis proved that, the mean ear weight and productive tillers per hill are important in yield determination of finger millet under drought condition. Among the varieties, Cv. PR-202 found relatively drought tolerant and this variety can be used as check for screening germplasm accessions against the drought stress. It is concluded that, moderate drought stress for 18 to 20 days with pan evaporation of around 4 mm per day is not a serious limitation under rainfed situations during kharif seasons.