Genetic architecture of root growth angle, seminal root numbers and early vigor in the synthetic hexaploid wheat diversity panel

Abstract Drought is a serious threat to crop production threatening food security worldwide. Seminal root growth angle (RA) and root number (RN) are important components of root system architecture (RSA) for the adaptability of plants under water stress. Likewise, leaf area (LA) in early vigor contributes against unpredictable drought stress. We characterized a collection of synthetic hexaploid wheat for root angle, seminal root numbers, and early vigor and identified loci associated with these traits using a 50K SNP array and genotyping-by-sequencing (GBS) platforms. LA showed a negative correlation with RN and a poor correlation with RA. In total, 39 marker-trait nucleotides (QTNs) were associated with LA, RA, and RN distributed over 10 wheat chromosomes. Out of these, 11 QTNs were associated with LA, 15 QTNs were associated with RA, and 13 QTNs were associated with RN. The higher frequency of favorable alleles in some synthetic hexaploid wheat accessions increased the phenotypic values and such synthetic wheats could be prioritized in wheat breeding to improve RSA and early vigor. These initial findings could be helpful for pre-breeding to improve wheat adaptability under drought stress conditions.