Suitability of carbon isotope discrimination, ash content and single mineral concentration for the selection of drought-tolerant winter rye

Carbon isotope discrimination (?) has been proposed as selection criterion for grain yield under dry conditions, and ash content (ma) and mineral concentration were suggested as surrogates for ?. In this study, the relationship between grain yield, ?, ma and mineral concentration (Si, Ca, K, Mg) was examined in 2011 and 2012 on 16 winter rye genotypes grown under severe drought, mild drought (2012 only) and well-watered conditions. Analyses were performed on mature flag leaves and grains. Highly significant differences between water regimes occurred for all measured traits. ?, ma and mineral concentrations were significantly correlated with grain yield under severe drought in 2011, but not in 2012 except for ? in flag leaf. ? was related to ma and mineral concentrations. Although the correlations were quite inconsistent, the results indicate that the measured traits can potentially be used as selection criterion for drought tolerance in rye. For a final statement about the suitability of these traits in rye breeding, the results should be secured with a larger and more diverse set of genotypes.