2014•Australian Journal of Crop ScienceRequires access
Determination of the relationship between water use efficiency, carbon isotope discrimination and proline in sunflower genotypes under drought stress
Öner Canavar, Klaus‐Peter Götz, Frank Ellmer, Frank‐M. Chmielewski, Mustafa Ali Kaynak
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Abstract
The aim of this study was to determine the effect of drought stress on four sunflower genotypes (Tarsan, Sanbro, TR-3080 and DKF-2525) and the relationship between some physiological and phenological characters at 30% (drought stress) and 60% (well-watered) irrigation from soil water capacity. Stress treatment was started from the emergence until R1 stage (bud visible) under the controlled conditions of greenhouse. The results showed that plants responses in some parameters such as leaf, stem and total dry weight, total leaf area, young fully developed leaf area, plant height, WUE (water use efficiency), RWC (relative water content), SLW (specific leaf weight) and Delta13C isotope (carbon isotope discrimination) are gradually declined under drought stress condition. On the other hand, some responses such as to proline content and chlorophyll of leaves are increased at the same drought condition. The highly significant relationships were found between both WUE and Delta13C isotope and proline, especially under drought condition. Generally, sunflower genotypes with lower SLW (leaf thickness) showed higher water content than those with higher SLW mainly due to highly negative relationship with RWC, under drought stress condition. However, the Sanbro cultivar can be used as a parental genotype in sunflower breeding programs due to its high RWC, WUE, total dry weight, high proline accumulation and low Delta13C isotope under drought stress conditions. Our study suggested that selection for WUE using indirect Delta13C isotope can presumably be of great value in sunflower breeding programs aimed at developing drought tolerant genotypes. It can also be confirmed that measuring young fully developed leaf area can be enough to determine the leaf area because there is a close correlation between total leaf area and the young fully developed leaves on a plant in both normal and drought conditions.