Identification of quantitative trait loci for carbon isotope ratio (δ13C) in a recombinant inbred population of soybean

KEY MESSAGE: QTL analysis identified 16 QTLs, grouped in eight loci on seven soybean chromosomes that were associated with carbon isotope ratio (delta(13)C) in a biparental recombinant inbred population. Drought is a major limitation to soybean yield, and the frequency of drought stress is likely to increase under future climatic scenarios. Water use efficiency (WUE) is associated with drought tolerance, and carbon isotope ratio (delta(13)C) is positively correlated with WUE. In this study, 196 F6-derived recombinant inbred lines from a cross of PI 416997 (high WUE) x PI 567201D (low WUE) were evaluated in four environments to identify genomic regions associated with delta(13)C. There were positive correlations of delta(13)C values between different environments (0.67