Document Type : Original Article

Authors

• Farzane Golestanifar ¹
• Sohrab Mahmoodi ^{2, 3}
• Hamid-Reza Fallahi ^{2, 3}
• Ali Shahidi ⁴

¹ PhD Students, University of Birjand, Iran

² Associate Professor, Department of Plant Production and Genetic Engineering, University of Birjand, Iran

³ Plant and Environmental Stresses Research Group, Faculty of Agriculture, University of Birjand, Iran

⁴ Associate Professor, Department of Water Science and Engineering, University of Birjand, Iran

Abstract

Introduction
Environmental disorders that significantly disturb the growth and yield of plants are considered as stress conditions and cause disturbances in biological. Drought stress is one of these environmental conditions which has been increased as a result of climate change and has been a negative effect on the yield of crops in the world. Every year about 12 million hectares of productive land has become dry and barren due to human activities and climate. More than 6000 varieties of quinoa are cultivated by farmers in the worlds. Quinoa is a plant responds to drought stress through escape, tolerance and avoidance of drought and has an extraordinary capacity for cultivation in dry and low-water soils because of its capabilities such as low inherent need for water, the maintenance of leaf surface and the ability to resume the speed of photosynthesis after drought stress. Titicaca, Redcarina and Giza-1 are three quinoa cultivars. Titicaca and Redcarina, were registered on December 14, 2009 and January 31, 2005, respectively, and are native to Denmark and Netherlands, respectively, and Giza1 is native to Egypt. Increasing yield in water deficit conditions requires the identification of genotypes resistant to drought stress. Different quantitative indicators have been provided to evaluate the reaction of genotypes in environmental conditions and also to determine their tolerance and sensitivity.
Materials and methods
In order to evaluate the indicators of drought stress tolerance of quinoa cultivars, a factorial experiment with four stress levels (100, 75, 50 and 25% of water requirement) and three varieties of quinoa (Titicaca, Giza-1 and Redcarina) were conducted with three replications in two locations (Birjand and Sarbisheh region) and two planting dates, spring (March) and summer (July) in 2018 and 2019. Evaluation of cultivars in terms of drought tolerance was done using stress sensitivity indices, such as tolerance (TOL), mean productivity (MP), stress tolerance index (STI), geometric mean productivity (GMP) and harmonic mean (HM). Decomposition into main components on yield under stress and non-stress conditions and drought stress tolerance indices were displayed in the form of a biplot diagram using STATISTICA software.
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.

Keywords

• Bi-plot
• Grain yield
• Principal components analysis
• Water requirement

Main Subjects

• Drought stress