| Maize(Zea mays L.) is an important crop which serves as forage, economic and grain crops. It plays an important role in food production security and economic development. Besides, two-thirds of the area of the maize distributed in arid and semiarid region. In this region, the water content of the soil surface is insufficient in early spring, which has an effect on seed germination, leading to the lack of seedlings and the yield of crop decline. However, the root of deep-sowing tolerant maize is deeper, which can make full use of deep soil moisture. Besides, the variety of deep-sowing tolerant maize can extend its mesocotyl and push the plumule to suitable soil and emergence. At present, the most effective measures to make the production of maize keep stability are to breed and grow deep-sowing tolerant maize varieties. In this study, wide-genome association and linkage analysis are used to explore the genetic analysis of the related traits of deep-sowing tolerant maize and to discover the major QTLs or genes. The main research contents and results are as follows:1. The related traits such as mesocotyl length, coleoptile length, shoot length and germination rate in a panel of 218 maize inbred lines with rich diversity at germination stages were detected, and were used to perform the genome-wide association analysis using 41 101 high quality SNP of MaizeSNP50 BeadChip. As a result, a total of twelve SNPs were found to be significantly associated with the related traits at a threshold of P<0.0001, these SNPs lie in chromosome bins 2.08.3.04、6.04、6.07、7.01、7.02 and bin 10.03. Meanwhile, five candidate genes were scanned. They are GRMZM2G163099. GRMZM2G012319、GRMZM2G148769、 GRMZM2G163861 and GRMZM2G149580. The production of encoded are CAP superfamily protein、SH3 domain-containing protein、 glucosamine-6-phosphate isomerases/6-phosphogluconolactonase、protein kinase domain and acyl carrier protein 4, respectively. These identified genes and SNPs will lay a foundation for cloning deep-sowing related genes in maize.2. The backcross populations were constructed with a cross between the long mesocotyl line CGJ and the short mesocotyl zheng 58, and the length of mesocotyl was used as the phenotypic datas. The linkage analysis were conducted in 3,6,10 chromosomes. The main results are as follows:(1) A total of 78 pairs of SSR primers were synthesized through database Maizegdb, and 30 pairs of polymorphic SSR markers were scanned between the parents CGJ and zheng58;(2) Based on backcross populations, the linkage maps of chromosome 3 and 6 were constructed through QTL Icimapping software. Among which, the linkage map of chromosome 3 contained 3 SSR markers umc2263、umc1102 and bnlg420 with a length of 7.07 cM, and the linkage map of chromosome 6 contained 9 SSR markers with a length of 65.07 cM, these markers are umc2311、phi126、umc230、umc2208、umc238、umc1883、umc2515、 bnlg1165 and umc1229. The order of the SSR markers is basically identical with that of IBM 2008 neighbor;(3) The major QTL analysis were conducted through the additive mapping method of QTL Icimapping software. The results showed that one major QTL was detected between the marker umc1102 and bnlg420 in bin 3.05 with a peak LOD of 4.33, which could explain 13.87% phenoltypic variance. |
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