Genetic dissection of soybean lodging tolerance in recombinant inbred-line populations of major Japanese and modern US varieties.

In soybean production, lodging poses a significant challenge to modern mechanized agriculture, such as the use of combine harvesters. Most Japanese varieties are prone to lodging because of the local weather conditions, such as wind and rain, resulting in a decline in productivity. In the United States (US), where mechanized agricultural production systems are prevalent, lodging tolerance (LT) is essential in soybean breeding. We thus used two recombinant inbred-line (RIL) populations developed by crossing major Japanese and modern US varieties for the genetic dissection of LT. One reliable quantitative trait locus (QTL) for lodging angle, qLT13-1, was identified from the first RIL population under two experimental conditions, early and late maturity groups of the first RILs in Ibaraki in 2018, and it accounted for 20.7%-20.9% of the phenotypic variation. An allele at qLT13-1 from a US variety was effective in improving LT under most experimental conditions. In addition, a QTL for LT was valid in the same genetic region of the other RIL populations. The effective allele, qLT13-1 is thus expected to be important for improving LT in soybean breeding, particularly in Japanese varieties.