Chromosome 1D as a possible location of a gene (s) controlling variation between wheat (Triticum aestivum L.) varieties for carbon isotope discrimination (Δ) under water-stress conditions

Summary

Carbon isotope discrimination (Δ) is an important character regarding to water-stress tolerance in wheat. In this study, F₂ backcross reciprocal monosomic crosses between varieties Falchetto (low Δ) and 18 monosomic lines of Oxley (high Δ) were used to identify chromosomal location of the gene (s) responsible for carbon isotope discrimination and therefore to detect allelic variation between the two wheat varieties. F₂ reciprocal monosomic families were initially assessed for dry matter production. F₂ families belonging to the chromosomes that indicated allelic variation for dry matter production were then assessed for Δ. The results revealed that reciprocal families belonging to chromosomes 1B, 7B, 1D and 5D indicated significant differences from which the family having chromosome 1D from Falchetto had the highest difference from its relevant reciprocal. Assessing the reciprocals of this chromosome for evapotranspiration efficiency (ETE) at the F₃ disomic generation indicated that the observed variation for Δ was translated into differences for ETE. These results indicate that chromosome 1D of Falchetto is promising in reducing Δ and that the improvement of wheat varieties for ETE can be done by selection for Δ. When selecting for Δ, managing the experiment is easier and there is no need to monitor the water use during the growth cycle.