Evaluation of drought stress tolerance indices of three quinoa cultivars in spring and summer planting dates in Birjand and Sarbisheh region

Results and discussion The results showed that in both regions the highest amount of STI, MP, GMP and HM indices, were recorded for Redcarina variety in all three levels of drought stress at spring cultivation, but they were belonged to Giza-1 at summer cultivation. Due to the dispersion of the results, SSI and TOL indices had less diagnostic power to evaluate the drought tolerance of quinoa cultivars. Principal components analysis showed that Redcarina cultivar was collinear with yield vector in stress condition and MP, GMP, STI and HM indicators and was located in yield potential and tension tolerant area in bi-plot diagram in two regions (Birjand and Sarbisheh) at spring cultivation. In summer cultivation, Giza-1 variety was located at sensitive to stress area and yield potential in bi-plot diagram and was collinear with grain yield vectors in non-stress conditions and MP, GMP, STI and HM indices in two regions. This showed the more yield of this variety in non-stress condition. In most of the planting dates and places were studied, Titicaca cultivar had collinearity with SSI vector or located at the closest position to this vector, which indicated that this cultivar was sensitive to stress. Conclusion In general, in July, Giza-1 variety and in March Redcarina variety were the most tolerance varieties and Titicaca was most sensitive cultivar to drought stress.