Document Type : Research Paper
Authors
Department of Plant Production and Genetics, Faculty of Agriculture, Urmia University, Urmia, Iran
Abstract
Introduction: Association mapping is used for many plants, including crop plants, with the aim of identifying the locus of quantitative traits. Abiotic stress including salinity stress is one of the main challenges facing agriculture, which can affect the final yield of the product, especially in the critical stages of growth, including the germination stage. Stress can affect the growth rate in different stages of growth and in more severe cases it can destroy the plant. Therefore, introducing and creating stress-tolerant plants, especially salinity stress, along with the use of other methods, can be somewhat helpful in dealing with the reduction of agricultural products.
Materials and Methods: In the current research, 64 varieties of bread wheat have been investigated in three different conditions including normal, 60 mM salt stress and 120 mM salt stress, with two repetitions in the form of a simple lattice design in the crop year 2021, in the Genetics laboratory of the Faculty of Agriculture of Urmia University and sodium chloride(NaCl) was used to create salinity. In this study, the traits of seedling length, shoot length, root length, ratio of shoot length to root length, seedling fresh weight, seedling dry weight, germination percentage, germination index, germination speed, average germination speed, average germination time, germination energy, seed vigor, relative germination index, relative germination speed and relative germination energy were studied. Also, 36361 SNP markers were used to identify gene locations controlling germination traits. TASSEL 5.0 software was used to association mapping of studied traits. For this purpose, the mixed linear model (MLM) method using PCA and Kinship matrices was used. Manhattan plots and LD plots were drawn using R studio 4.1.1 software.
Results and Discussion: In the present study, 330, 153, and 116 MTAs were identified for normal conditions, 60 mM salinity stress conditions, and 120 mM salinity stress conditions, respectively. Meanwhile, in normal conditions, 43 important markers in chromosomes 1B and 7B were related to germination indices. In the condition of 60 mM salinity stress, the number of 32 important markers in chromosomes 1 B, 2 B, 6 A, 5 A and 6 B and in the condition of 120 mM salinity stress, the number of 14 important markers in chromosomes 1 B, 3 A and 3 B were related to the control of plant traits. The sequence of all the significant markers in Ensembl plant database was checked. Examination of the sequences showed that MTAs are involved in important biological and molecular processes such as signal transduction, signaling pathways of kinase presentation, defense response, response to biological stimuli, hydrolase metabolism, polysaccharide binding, etc. In the condition of 60 mM salinity stress, an important pathway including the metabolism of proline, arginine, beta-alanine, and in the condition of 120 mM salinity stress, the ABC transporter pathway was identified.
Conclusion: The MTAs and known pathways based on the results of this study are very important, and after confirming the results in biparental populations and performing additional tests, these findings can be used in marker-assisted breeding and selection programs for wheat plants.
Keywords
Main Subjects
)