Identification of Soybean Yield QTL in Irrigated and Rain-Fed Environments
Geung‐Joo Lee, Sung-Woo Lee, Tommy E. Carter, Grover Shannon, H. R. Boerma
Abstract
Drought is the primary abiotic stress that limits yield of soybean (Glycine max (L.) Merr.). The study aimed to identify yield-related quantitative trait loci (QTLs) in soybeans using a population of 160 F4-derived lines from ‘Hutcheson’ × PI 471938 crosses, which were cultivated under rain-fed and irrigated conditions. Seed yield was determined based on a total of nine irrigated and five rain-fed environments over two years. Twenty and twenty-seven SSR markers associated with yield (p ≤ 0.05) were identified in the irrigated and rain-fed environments, respectively. Four markers accounted for 22% of the yield variation in the irrigated environments (IR-YLD) and five markers explained 34% of the yield variation in the rain-fed environments (RF-YLD). Two independent IR-YLD and RF-YLD QTLs on chromosome (Chr) 13 (LG-F) were mapped to the Satt395-Sat_074 interval (4.2 cM) and near Sat_375 (3.0 cM), which explained 8% (LOD = 2.6) and 17% (LOD = 5.5) of the yield variation, respectively. The lines homozygous for the Hutcheson allele at the IR-YLD QTL linked to Sat_074 averaged 100 kg ha−1 higher yield than the lines homozygous for the PI 471938 allele. At two independent RF-YLD QTLs on Chr 13 and Chr 17, the lines homozygous for the PI 471938 alleles were 74 to 101 kg ha−1 higher in yield than the lines homozygous for the Hutcheson alleles. Three of the five significant SSR markers associated with RF-YLD were located in a genomic region known for canopy-wilting QTLs, in which the favorable alleles were inherited from PI 471938. The identification of yield-QTLs under the respective rain-fed and irrigated environments provides knowledge regarding differential responses of yield under different irrigation conditions, which will be helpful in developing high-yielding soybean cultivars.