The Genotypic Variability among Short-Season Soybean Cultivars for Nitrogen Fixation under Drought Stress

• Published in: Plants (Basel) 2023-02, Vol.12 (5), p.1004
• Main Authors: Liyanage, Dilrukshi Kombala, Torkamaneh, Davoud, Belzile, François, Balasubramanian, Parthiba, Hill, Brett, Thilakarathna, Malinda S
• Format: Article
• Language: English
• Subjects: Canada; candidate genes; Chromosomes; Coffee; Crop yield; Cultivars; Drought; Drought resistance; Droughts; Environmental aspects; Field capacity; Fixation; Gene mapping; Genes; Genetic variability; genome wide association study; Genome-wide association studies; Genomes; Genomics; Genotype; Horticulture; Legumes; Moisture content; Nitrogen; Nitrogen fixation; Nitrogenation; Nodules; Nucleotides; Parameters; Physiological aspects; Plant breeding; Plant growth; Quantitative genetics; Quantitative trait loci; quantitative trait locus; R&D; Research & development; Root nodules; Seeds; Single nucleotide polymorphisms; Single-nucleotide polymorphism; Soybean; Soybeans; Stress (Physiology); symbiotic nitrogen fixation
• ISSN: 2223-7747; 2223-7747
• DOI: 10.3390/plants12051004

Soybean fixes atmospheric nitrogen through the symbiotic rhizobia bacteria that inhabit root nodules. Drought stress negatively affect symbiotic nitrogen fixation (SNF) in soybean. The main objective of this study was to identify allelic variations associated with SNF in short-season Canadian soybean varieties under drought stress. A diversity panel of 103 early-maturity Canadian soybean varieties was evaluated under greenhouse conditions to determine SNF-related traits under drought stress. Drought was imposed after three weeks of plant growth, where plants were maintained at 30% field capacity (FC) (drought) and 80% FC (well-watered) until seed maturity. Under drought stress, soybean plants had lower seed yield, yield components, seed nitrogen content, % nitrogen derived from the atmosphere (%Ndfa), and total seed nitrogen fixed compared to those under well-watered conditions. Significant genotypic variability among soybean varieties was found for yield, yield parameters, and nitrogen fixation traits. A genome-wide association study (GWAS) was conducted using 2.16 M single nucleotide single nucleotide polymorphisms (SNPs) for different yield and nitrogen fixation related parameters for 30% FC and their relative performance (30% FC/80% FC). In total, five quantitative trait locus (QTL) regions, including candidate genes, were detected as significantly associated with %Ndfa under drought stress and relative performance. These genes can potentially aid in future breeding efforts to develop drought-resistant soybean varieties.