Quantitative trait loci mapping for flooding tolerance at an early growth stage of soybean recombinant inbred line population

Flooding stress causes a significant yield reduction in soybean. The early growth of soybean in Korea coincides with the rainy season, potentially exposing to flooding stress. Greenhouse experiments were conducted to map the quantitative trait loci (QTL) for flooding tolerance in soybean and to identify and investigate candidate genes near the QTL hot spots. Flood stress was imposed at V1–V2 stage on a recombinant inbred line population (‘Paldalkong’ × ‘NTS1116’), and leaf chlorophyll content (CC) and shoot dry weight (DW) were measured under control and flooded conditions. The genetic map was constructed using 180K Axiom® SoyaSNP markers. The QTL were analysed under control and flooded conditions as well as for index (ratio of CC or DW under flooded to control, CCI and DWI) and flooding tolerance index (FTI, mean of CCI and DWI). A total of 20 QTL with LOD scores 3.59–19.73 causing 5.8%–33.3% phenotypic variation were identified on nine chromosomes. Chromosomes 10, 12 and 13 harboured relatively more stable QTL. Results of this study could be useful to further understand the genetic basis of soybean's flooding tolerance and applied in breeding programmes.