Abstract
Different physiological traits have been proposed as key traits associated with yield potential as well as performance under water stress. The aim of this paper is to examine the genotypic variability of leaf chlorophyll, stem water-soluble carbohydrate content and carbon isotope discrimination (Δ13C), and their relationship with grain yield (GY) and other agronomical traits, under contrasting water conditions in a Mediterranean environment. The study was performed on a large collection of 384 wheat genotypes grown under water stress (WS, rainfed), mild water stress (MWS, deficit irrigation), and full irrigation (FI). The average GY of two growing seasons was 2.4, 4.8, and 8.9 Mg ha−1 under WS, MWS, and FI, respectively. Chlorophyll content at anthesis was positively correlated with GY (except under FI in 2011) and the agronomical components kernels per spike (KS) and thousand kernel weight (TKW). The WSC content at anthesis (WSCCa) was negatively correlated with spikes per square meter (SM2), but positively correlated with KS and TKW under WS and FI conditions. As a consequence, the relationships between WSCCa with GY were low or not significant. Therefore, selecting for high stem WSC would not necessary lead to genotypes of GY potential. The relationship between Δ13C and GY was positive under FI and MWS but negative under severe WS (in 2011), indicating higher water use under yield potential and MWS conditions.
Highlights
Since the Green Revolution the yields of wheat and other cereals have increased considerably in many regions of the world, including Chile (Calderini and Slafer, 1998; Engler and del Pozo, 2013; del Pozo et al, 2014), as a result of genetic improvement and better agronomic practices
In this study we investigated the genotypic variability of flag leaf chlorophyll content, stem water-soluble carbohydrate (WSC) accumulation at anthesis and the 13C of mature kernels, as well as the relationship of these traits with grain yield (GY) and its agronomical components, in spring bread wheat under contrasting water conditions in a Mediterranean environment
Genotypes with higher numbers of fertile tillers would lead to higher numbers of kernels per m2 and GY under terminal water stress and non-stress conditions
Summary
Since the Green Revolution the yields of wheat and other cereals have increased considerably in many regions of the world, including Chile (Calderini and Slafer, 1998; Engler and del Pozo, 2013; del Pozo et al, 2014), as a result of genetic improvement and better agronomic practices. The yield potential, i.e., the yield achieved when the best available technology is used, has increased almost linearly since the sixties, in more favorable environments where soil water availability is not limited (Zhou et al, 2007; Fischer and Edmeades, 2010; Matus et al, 2012; del Pozo et al, 2014). The potential yield and water-limited yield of wheat needs to continue increasing in order to cope with future demand for food, which is a consequence of the growing population and changes in social habits (Fischer, 2007; Hawkesford et al, 2013), and to reduce the negative impacts on crop productivity of global climate change (Lobell et al, 2008; Lobell and Gourdji, 2012)
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