Relationship between Water Use Efficiency and Î"13C Isotope Discrimination of Safflower (Carthamus tinctorius L.) under Drought Stress

Abstract

Drought stress is one of the most limiting factors in agricultural productivity because of its highly negative effect on photosynthesis and growth of plants. The main objectives of this study were to determine the performance of four selected safflower genotypes (Remzibey, Dinçer, Balcı and TRE-ASL09/14) against drought stress. The relationship between water use efficiency (WUE) and δ 13 C (isotope discrimination) was investigated under well watered (60%) and drought stress (30%) irrigation in controlled conditions in a green house. The result showed that drought stress clearly reduced plant biomass, leaf area, leaf number, relative water content (RWC), specific leaf weight (SLW), WUE and δ 13 C in all genotypes, while chlorophyll increased under drought stress. There were significant differences between performances of all safflower genotypes in terms of response to drought stress. High WUE and low δ 13 C discrimination under drought stress were inversely associated with a strong regression relationship (R 2 =0.75). The analysis of δ 13 C revealed a substantial variation in water use efficiency among the genotypes under drought stress. It was revealed that low δ 13 C discrimination types had high WUE, RWC and total biomass under drought stress. Thus, the ability of the low δ 13 C genotypes (high water use efficiency, WUE) to maintain higher RWC may provide a good indication of the differences in drought tolerance of safflower genotypes differing in δ 13 C. Overall, on the basis of the consistent percentage reductions in plant heights, total dry weight, leaf area, RWC, WUE and low δ 13 C, the TRE-ASL09/14 new breeding line was found to be more drought tolerant when compared with the other safflower hybrids under drought stress. As a result of our study it is suggested that there is a strong relationship between WUE and lower δ 13 C under drought stress, indicating that it may be used as a selection criterion for developing safflower genotypes with drought tolerance.

Physiological response and productivity of safflower lines under water deficit and rehydration

“…WUE can be considered as a mechanism of stress tolerance and leads to an increase in productivity due to changes in water use (Canavar et al 2014). The decrease of WUE after the period of stress will result in a reduction in the productivity of these lines, indicating a greater susceptibility to water stress.…”

“…It is an oilseed crop, from the Asteraceae family, not very popular compared to other oil crops such as soybean, sunflower and peanut because it is not widely cultivated around the world (Canavar et al 2014). …”

“…In recent years, its importance has been growing, mainly for the production of biofuels (Canavar et al 2014).…”

Methods of soil moisture maintenance for production of sunflower under controlled conditions

“…According to several researches, the sunflower crop positively responds to soil water availability. Farahvash et al, (2011) and Canavar et al, (2014) reported a strong relationship between productivity and irrigation. Moreover, Nezami et al, (2008) indicated that excessive or drought conditions resulted in a reduction in the structural and productive traits of sunflower.…”

Assessment of ET-HS Model for Estimating Crop Water Demand and Its Effects on Yield and Yield Components of Barley and Wheat in Semi-Arid Region of Iran

“…Iran is from arid and semi-arid regions and finding ways to overcome water deficiency has been always from research priorities to produce crops for growing population, because in those regions, drough is an important factor limiting crop production (Soleymani et al, 2011;Ghaffari et al, 2012;Soleymani & Shahrajabian, 2012;Esmaeili & Soleymani, 2013;Canavar et al, 2014;Hajiboland et al, 2014;Hajiboland et al, 2015;Ashraf et al, 2016;Soleymani et al, 2016;Shahrajabian & Soleymani, 2017;Shahrajabian et al, 2017;Soleymani & Shahrajabian, 2017). A technique for efficient management of irrigation water is to use new models for determining water demand and scheduling irrigation along with decreasing the susceptibilty of crop to water deficiency and improving their tolerance to drought by breeding (Soleymani et al, 2012), some of these models estimate the yield under water stress condition (Geerts & Raes, 2009), and others are related to climatic changes and evaluate the yearly variations of the yield during drought periods (Jones et al, 2003).…”