Effective Selection Indices for Improving Tolerance to Water Stress in Millet Germplasm

To evaluate the yield potential of 96 ecotypes including 48 proso millet (Panicum miliaceum) and 48 foxtail millet ecotypes (Setaria italica) along with four check cultivars under well-watered and water stress conditions, a field experiment was carried out in the Agricultural Research Institute, Meybod, Yazd, Iran, during 2013-2014 using an incomplete block design with two replications. Based on the grain and forage yield, tolerance (TOL), stress susceptibility index (SSI), mean productivity (MP), harmonic mean (HM), geometric mean productivity (GMP) and stress tolerance index (STI) as drought tolerance indices were calculated and tolerant genotype selection index (TGSI) was conducted along with factor analysis. Among all the ecotypes and according to all indices, ecotypes S100, P10, S52, P97, S108, P20, S55, S104 and S18 were selected as the most drought-tolerant and grain yield potential. In addition, ecotypes P34, S104, P97, S39, S53, P102, P23, P5, S18, S13, S12, P92, and S3 were tolerant ecotypes with high potential forage yield. The results indicated that the ranking by TGSI was almost similar to the results obtained through the factor analysis. In addition, TGSI has had easier calculations than factor analysis and other methods. Therefore, it is suggested to explore the stress tolerant ecotypes in practical plant breeding.