Elucidation of the Genetic Architecture of Water Absorption Capacity in Hard Winter Wheat Through Genome Wide Association Study.

Water absorption capacity (WAC) influences various aspects of bread making, such as loaf volume, bread yield, and shelf life. Despite its importance in the baking process and end-product quality, its genetic determinants are less explored. To address this limitation, a genome-wide association study was conducted on 337 hard wheat (Triticum aestivum L.) genotypes evaluated over 5 years in multi-environmental trials. Phenotyping was done using the solvent retention capacity (SRC) test with water (SRC-water), sucrose (SRC-sucrose), lactic acid (SRC-lactic acid), and sodium carbonate (SRC-carbonate) as solvents. Individuals were genotyped using genotyping-by-sequencing to detect single nucleotide polymorphisms across the wheat genome. To detect the genomic regions that underline the SRCs and gluten performance index (GPI), a genome-wide association study was performed using six multi-locus models using the mrMLM package in R. Adjusted means for SRC-water ranged from 54.1% to 66.5%, while SRC-carbonate exhibited a narrow range from 84.9% to 93.9%. Moderate to high genomic heritability values were observed for SRCs and GPI, ranging from h2 = 0.61 to 0.88. The genome-wide association study identified a total of 42 quantitative trait nucleotides (QTNs), of which five explained over 10% of the phenotypic variation (R2 >= 10%). Most of the QTNs were detected on chromosomes 1A, 1B, 3B, and 5B. Few QTNs, such as S1A_5190318, S1B_3282665, S4D_472908721, and S7A_37433960, were located near gliadin, glutenin starch synthesis, and galactosyltransferase genes. Overall, these results show WAC to be under polygenic genetic control, with genes involved in the synthesis of key flour components influencing overall water absorption. A total of 42 marker-trait associations related to solvent retention capacity traits and gluten performance index were identified. Chromosomes 1A and 1B harbored the highest number of marker-trait associations in this study. Most of marker-trait associations identified in this study were frequently colocalized with gluten glycosyltransferase genes. Bread is mainly made from water and flour. The way flour absorbs water is crucial for bread quality. This study looked at the genetics behind this in 337 types of winter wheat. We used a method called a genome-wide association study to find links between wheat DNA and how well it absorbs water. We tested the wheat's water absorption with four different liquids, and the DNA of the flour was analyzed by a method called genotyping-by-sequencing. Our study found 42 important spots in the wheat's DNA on 17 chromosomes that are connected to how well the wheat absorbs water. Some of these spots are near genes controlling flour components. This means the water absorption in wheat is controlled by many small genetic factors and genes affecting flour components, which might affect the water absorption capacity of the flour. Understanding these can help us make better bread by choosing the right wheat.