A GH; A SH; M R; H Z
Abstract
Deficit irrigation, as a limiting factor for growth, will affect physiological characteristics of plants. In order to investigate the effects of deficit irrigation on yield, chlorophyll fluorescence, dry weight of stems and leaves, and leaf area index of sunflower, this study was performed at the research ...
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Deficit irrigation, as a limiting factor for growth, will affect physiological characteristics of plants. In order to investigate the effects of deficit irrigation on yield, chlorophyll fluorescence, dry weight of stems and leaves, and leaf area index of sunflower, this study was performed at the research farm of Agriculture and Natural Resources University of, Sari, Iran, in 2013. The experimental treatments were arranged as randomized complete block design with three replications. The irrigation regimes consisted of full irrigation (FI), regulated deficit (DI75, DI55), and partial root-zone drying irrigation (PRD75, PRD55). The results indicated that the effect of irrigation treatments on yield, photosynthetic efficiency, maximum fluorescence (Fm), minimum fluorescence (Fo), leaf area index, shoot dry weight, leaf dry weight, and head dry weight was significant. Comparison showed that water stress significantly decreased grain yield, photosynthetic efficiency index and maximum fluorescence (Fm), whereas the minimum fluorescence (Fo) was increased. The maximum seed yield (5148 kg ha-1) was attained in full irrigation treatment and had no difference with PRD75 treatment. The maximum leaf area index at the end of the growing season was 4.3 and recorded in FI and had no difference with PRD75, DI75 and PRD55. Overall, treatment PRD75 is recommended since it reduced water consumption by 16.8 percent relative to FI treatment and had no significant difference with full irrigation treatments (FI) in terms of seed yield, quantum yield, and other growth parameters.
a esmaili; h o; a b
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 ...
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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.