Genetic and physiological bases for variation in water use efficiency in canola

Drought stress due to water deficiency threatens production of canola worldwide. Carbon isotope discrimination (Δ13C), a trait that can be used to assess efficient water use, provides an opportunity to exploit natural variation in canola for stable production. Here, we show that substantial genetically controlled phenotypic variation in water use efficiency (WUE) component trait, Δ13C (20.4 to 23.6‰) exists among accessions of canola. Quantitative trait loci (QTL) analysis revealed ten loci for Δ13C, each accounting for 2.5% to 16.5% of the genotypic variation. One of the significant QTL for Δ13C was co‐localized with a QTL for flowering time, a trait implicated in drought escape and was mapped in the vicinity of the FLOWERING LOCUS T (FT) on chromosome A07. Gene expression analyses revealed that among FT paralogs, BnC6.FTb expression was significantly correlated (r = 0.33, p