Carbon Isotope Discrimination and Grain Yield Variations among Tetraploid Wheat Species Cultivated under Contrasting Precipitation Regimes

Abstract

Nineteen accessions belonging to six tetraploid wheat species were evaluated and compared for carbon isotope discrimination and grain yield during two successive cropping seasons (1995 and 1996) under Mediterranean rainfed conditions. The two seasons differed markedly in precipitation regime. A wide variation for the measured traits was observed among the 19 accessions for carbon isotope discrimination and grain yield in both years. Significant differences were also noted between species accessions for Δ and grain yield. In both years, Triticum timopheevi (AG genome) showed lower Δ values than the other tetraploid species (all carrying the AB genome). Positive correlations were observed between Δ and grain yield in both years. The use of carbon isotope discrimination as an indirect selection criterion for yield under stress and the potential benefits of some alien tetraploid species in improving drought tolerance in durum wheat are discussed.

Effects of water stress and nocturnal temperature on carbon allocation in the perennial grass, Leymus chinensis

“…The present study indicates that the δ 13 C values are more positive at normal temperature than during nocturnal warming, which is inconsistent with the findings of Su et al (2000). Furthermore, it has been shown that the carbon isotope discrimination (Δ) is positively correlated with the wheat grain yield (Merah et al 2001), which is also inconsistent with the present result, which shows that the sink organ (root) has more positive δ 13 C values. However, Qian et al (2004) reported that the large decrease in δ 13 C of grass is paralleled by limited root growth.…”

Combined effects of elevated CO2 and soil drought on carbon and nitrogen allocation of the desert shrub Caragana intermedia

“…The result of Qian et al (2004) shows that great reduction in δ 13 C of a grass is paralleled with a decrease in root growth. However, Merah et al (2001) reported that the carbon Δ is positively associated with wheat grain (a sink organ) yield, being similar the present results showing an increase both in Δ values and biomass in roots. For the perennial grass Leymus chinensis, higher temperature leads to greater decrease in carbon isotope discrimination in root than in leaf, showing a low adaptation to water stress (Xu and Zhou 2005a).…”

Genetic Variance in Cadmium Tolerance and Accumulation in Wheat Materials Differing in Ploidy and Genome at Seedling Stage

“…Along with evolution from diploid to hexaploid (the cultivated common wheat), both yield and quality traits are improved (Merah et al 2001, Chinnusamy and Khanna-Chopra 2003, Xiong et al 2006). The other physiological traits also change during the evolution.…”