Effect of different physiological traits on grain yield in barley grown under irrigated and terminal water deficit conditions

Abstract

SU MMARYDrought is the main factor limiting the productivity of crops in Mediterranean areas. The introduction of physiological traits into crops that improve their tolerance to drought is necessary if yields under these conditions are to be efficiently improved. The effect of drought on different gas exchange variables, i.e. net photosynthesis (A), stomatal conductance (g s ) and leaf chlorophyll concentration (Chl), and the relationship of these variables with yield were studied in 12 barley genotypes grown under irrigated and terminal drought conditions. The variable most sensitive to water deficit was g s (mean reduction 43 % with respect to control conditions), followed by A (mean reduction 34 %). The mean reduction of yield by terminal drought was 27 %. A significant correlation was seen between these physiological traits and yield. The effect of water deficit on A, g s and Chl was smaller in the breeding lines than in the traditional varieties assayed, in agreement with the results found for yield. These results suggest a potential indirect selection of physiological characteristics in these breeding lines that allow greater tolerance to drought. The response of the different genotypes examined was not homogeneous across all the variables analysed. This variability is important in programmes aiming to obtain drought-tolerant genotypes via the optimization of traits such as those above.

Response of common barley (Hordeum vulgare L.) physiological parameters to agricultural practices and meteorological conditions

“…The gs of barley breeding lines ranged from 0.022 to 0.057 mol m -2 s -1 (P ≤ 0.001) (Jiang et al, 2006). Gonzalez et al (2010) also confirms significant varietal influence on gs for barley (P < 0.001). Varietal influence on gs can be explained by different response of varieties to solar radiation and leaf temperature differences.…”

“…It is important for barley growers to better understand the factors affecting the photosynthetic productivity. Studies performed on different crops have indicated that the climate warming and changes in moisture and thermal regimes intensely influence the photosynthesis process (Gonzalez et al, 2010;Waraich et al, 2011 a;Zhao et al, 2011). Knowledge of the physiological traits that limit yield under inimical conditions provides new opportunities for future breeding and growing strategies (Tambussi et al, 2005;Gonzalez et al, 2010;Kalaji et al, 2011).…”

“…Studies performed on different crops have indicated that the climate warming and changes in moisture and thermal regimes intensely influence the photosynthesis process (Gonzalez et al, 2010;Waraich et al, 2011 a;Zhao et al, 2011). Knowledge of the physiological traits that limit yield under inimical conditions provides new opportunities for future breeding and growing strategies (Tambussi et al, 2005;Gonzalez et al, 2010;Kalaji et al, 2011). Photosynthetic traits significantly differ between the different genotypes (Anyia, Herzog, 2004;Mamnouie et al, 2006), and between both open field and greenhouse growing conditions (Ibrahim, Jaafar, 2011).…”

“…Intensity of photosynthesis varies throughout plant development stages (Tsialtas, Maslaris, 2008;Efthimiadou et al, 2010). The reduction of photosynthesis has direct effect on crop growth and yield (Gonzalez et al, 2010). This is important to consider while developing new technologies of barley cultivation.…”

Response of coleoptiles to water deficit: growth, turgor maintenance and osmotic adjustment in barley plants (Hordeum vulgare L.)

“…In environments affected by drought the improvement of yield is difficult given the low heritability of this trait and because of the variable quantity and temporal distribution of soil water. The use of secondary traits, including physiological traits [1], has been proposed as a possible solution to this problem. In this approach the identification of traits that contribute towards drought tolerance and that can be used as selection criteria in improvement programmes is essential for increasing selection efficiency, especially in climates in which water availability is low.…”