Identification of Low-Light-Resistant Germplasm and Related Loci of Soybean

Low-light stress will lead to abnormal soybean growth and a subsequent yield reduction. Association mapping is a useful alternative to linkage mapping for the detection of marker-phenotype associations. This study aimed to evaluate low-light-resistant soybean accessions and identify markers associated with low-light resistance. We assessed the plant height, stem diameter, number of bean pods, and cotyledon height of soybean plants under low and normal light conditions. These traits were evaluated in 185 soybean accessions, and the accessions 11HX-020, 11HX-025, 11HX-029, 11HX-064, 11HX-127, 11HX-166, 11HX-183, and 11HX-216 showed stable performance under low-light conditions. These 185 accessions were genotyped with 639 single-nucleotide polymorphism (SNP) markers and 98 simple sequence repeat (SSR) markers. A total of 75 markers-i.e., traits associated with low-light resistance-were identified. These associated markers were distributed on 14 linkage groups (LGs) of soybean, and some markers were associated with two or more traits. According to the results, excellent germplasm material and low-light-resistance related markers can be used for low-light resistance breeding of soybean and will help identify the low-light resistance genes.