Genome-wide Association Analysis Of Salt Tolerance In Maize Seedlings

Soil salinization is an important factor that affected agricultural production and ecological environment. To date, there are～20% cultivated fields affected by salinization. The trend of soil salinization is more serious in arid and semi-arid regions. Salinity affects 4 × 107 ha of agriculture land which limited agricultural development in China. Breeding salt-tolerant varieties is one of the effective ways to alleviate the influence of soil salinization on agricultural production. Enhancing the salt-tolerant capacity of crop has important practical significance for the expansion of arable land and improvement of agricultural production.Maize is one of the important forage crops and it can be provided as raw material for industry. As the population grows rapidly, the demand for increased corn production is extremely urgent. Till now, though soil salinization has influenced the maize yield, there is still no unified evaluation of salinity tolerance for maize. Therefore, it is critical to construct a sanity evaluation system of maize and to understand the genetic mechanism that maize response to salinity.In this study, we used the concentration of 120mM NaCl as the salinity stress to treat 420 maize samples at seedling stage to evaluate their four physiology indexes including plant height, upper ground fresh weight, root fresh weight and whole plant fresh weight. Genome-wide association studies (GWAS) was performed to infer the potential loci or genes that are responsible for the four traits. Among genes with identified SNPs residing in, several potential stress responsible genes were found. For example, GRMZM2G113135, which is potentially responsible for regulating auxin biosynthesis; GRMZM2G137839 with homolog to rice salt tolerance gene OsAPxl was also found, suggesting it may play a important role in maize salt tolerance.