Effect of Drought Stress on Grain Yield, Proline Changes, Photosynthetic Pigments, and Leaf Relative Water Content of the New Genotypes of Safflower

Document Type : Research Paper

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Abstract

In terms of efficiency and economy of water resources, cultivation of safflower, as an important oilseed crop acclimated to the county’s conditions, can be effective. A field trial aimed to evaluate the grain yield and some physiological properties of the new safflower genotypes under drought stress was performed as split plot experiment in randomized complete block design (RCBD) with three replicates in ‌2010-2011‌‌ crop season. Drought stress levels were applied after flowering as soil water potential (-0.5 i.e. the control, -3.5, and -6.5 atm) and allocated to the main plots, while the new safflower genotypes (Sofeh, Goldasht, Mec12, 411, Mec50, Mec141, C44, Padideh, and Kw2) were planted in the sub-plots. Analysis of variance showed that drought stress had significant effect on thousand grain weight, grain yield, photosynthetic pigments, leaf relative water content (RWC) and proline content. By increasing drought stress, the content of photosynthetic pigments, thousand grain weights, and proline increased, but leaf relative water content and grain yield decreased. The highest and the lowest grain yields belonged to Goldasht and Kw2 genotypes, respectively, and Mec141 was the best selected genotype tolerant to drought stress. Correlation between thousand grain weight, grain yield and proline content was significant, which reflect their importance in increasing grain yield.

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