Abstract Global food insecurity looms as climate change and stagnant crop yields threaten food supply. Soybeans, the second most produced crop by acreage in the US, are particularly at risk, necessitating stress-resilient cultivars for future conditions. A soybean diversity panel of 285 accessions was studied over two years for gas exchange and leaf morphology traits. Genome-wide association analysis identified 44 marker-trait associations (MTAs), including one linked to photosynthetic carbon assimilation, 4 to stomatal conductance, 2 to water use efficiency, 6 to intercellular CO 2 , and 11, 7, and 13 to leaf area, dried leaf mass, and specific leaf area, respectively. Notably, SNP ss715612250 (Chr. 12) was associated with water use efficiency and intercellular CO 2 (Ci), while SNPs ss715635425 and ss715635417 (Chr. 19) were linked to leaf morphology traits. In a 2 Mb region around these markers, approximately 20 colocalized genomic regions were identified for multiple traits focused on in the current study. Candidate gene mining in a 500 kb window revealed potential genes, including those related to auxin signaling ( ARF19, NDL1 ), chloroplast stroma regulation ( cICDH ), stomatal movement ( OST1 , PIP2b ), and leaf growth ( TCP5, ZPR3 ). This study identified high net photosynthesis and water use efficiency cultivars, potential markers, and candidate genes for future introgression breeding, marker-assisted selection, and gene functional validation.
Abendroth-McGhee et al. (Mon,) studied this question.