Root characteristics of an elite spring wheat panel under contrasting water treatments and their genome-wide association study

• Published in: Rhizosphere 2021-09, Vol.19, p.100413, Article 100413
• Main Authors: Khodaee, Sayyed Mohammad Mehdi, Hashemi, Maryam, Mirlohi, Aghafakhr, Majidi, Mohammad Mahdi, Sukumaran, Sivakumar, Esmaelzaeh Moghaddam, Mohsen, Abdollahi, Mohammad
• Format: Article
• Language: English
• Subjects: Crop water stress; Genome-wide association study; Molecular marker trait association; Root phenotype markers; Triticum aestivum
• ISSN: 2452-2198; 2452-2198
• DOI: 10.1016/j.rhisph.2021.100413

Wheat occupies the largest global harvested area of any crop, most of which has been affected by abiotic stress. Root features are challenging to enhance through conventional selection strategies, and therefore, molecular approaches such as genome-wide association studies (GWAS) may help overcome some of the limitations. In the current study, 170 elite spring wheat lines were studied for root and shoot characteristics under water-stress and non-stress environments in two replications of field soil tubes. Root and shoot phenotypes especially network root length, network root volume and plant highest showed significant decrease under water-stress in contrast with well-watered condition. Also, the studied factors revealed distinct aspects of the population, which are called “root development”, “deep rooting system”, “plant vigor”, and “spike properties” via principal component analysis (PCA). The population was genotyped using 90 K Illumina SNPs and a total of 14,968 markers used in GWAS. In total, 186 significant marker-trait associations were identified on 16 chromosomes, some of which confirmed previously reported loci for root length. Several new loci affecting root development in wheat were identified in the present study. Several MTAs on specific chromosomes were identified exclusively under well-watered condition as well as water-stress environment, particularly 58 significant ones related to the root development component. The most significant associations were found for the deep rooting component. Also, candidate loci were identified having significant effect on different aspects of the studied population particularly the deep rooting system and the root development under water-stress environment. The candidate SNPs identified in the current study were validated by the whole WAMI population's field data, emphasizing the reliability of performed GWAS for identifying loci affecting root quantitative-related traits. These results improve our understanding of the genetic basis of root system architecture under well-watered and water-stressed environments.