Association Analysis For Wheat Nitrogen Efficiency Traits Based On Molecular Marker Of SNP

Wheat is the second food crops in China, its high and stable yield has important strategic significance for ensuring food security in China. However, the nitrogen use efficiency in wheat production is low and the excess nitrogen coexist which lead to wheat production cost and environment pollution risk increases year by year, seriously affected the sustainable development of China's wheat production. Therefore, cultivating nitrogen efficient wheat varieties to improve the utilization rate of nitrogen fertilizer is one of the important task to the current agricultural field. Nitrogen use efficiency is a complex quantitative trait which controlled by multiple genes, screening nitrogen efficiency associated marker loci related traits will offer some reference for wheat breeding.A variety population was used as the material in this study. It took a combination of seedling experiments which were finished by hydroponics and mature period experiments were carried out in the field. All the population were grown in low nitrogen?LN? condition ? high nitrogen?HN? condition and in normal nitrogen?MN? conditions as a control. Effects of different nitrogen content on N utilization efficiency at seedling and mature period and final yield were studied. Based on mass molecular marker of SNP, the association analysis of wheat N efficiency-related traits?biomass, N concentration, N absorption and utilization efficiency? and yield-related traits?plant height, spike length, spike, grain weight etc.? were carried on, and some important sites of N nutrition-related traits were detected. The main results are as follows:?1? Different N treatments have a significant impact on nitrogen nutrition traits of wheat. Compared with normal N treatment?T1?, N content and concentration were si gnificantly decreased under wheat seedling stage, but the dry weight?N utilization and root-shoot radio of biomass and N content were significantly increased under the T2 treatment, which were not significant under T3 treatment while other traits were all si gnificantly increased. Compared with the control treatment?T4?, at mature period unde r LN treatment?T5? N content and concentration decreased significantly, plant weight decreased significantly, spike length?spike number per plant and N utilization efficienc y has no significant differences, grain number per spike decreased significantly in the first year, but plant weight has no significant differences, N utilization efficiency and grain number per spike increased significantly and spike length?spike number per plant decreased significantly in the next year, this may be caused by two years in differen t environmental factors.?2? 2,278 siteswere detected at seedling experiments, including 105 stable associati on sites which were associated with three or more traits. Single marker loci phenotypi c variation ranged from 7.31% to 20.8%. Twenty-one markers were screened to signifi cantly associate with six or ten traits. These ten markers were Excalibur_c63563₃70?D_contig31797₃13?RAC875_c39966₂80?wsnp_Ex_c6400₁1123059?CAP7_rep_c12537₈1?wsnp_Ku_rep_c72700₇2370664?Bob White_c18267₂96?Ra_c15638₈58?Exca libur_c12085₂76?Bob White_rep_c52979₁81?Excalibur_c115824₂67?Bob White_c23839₁19?Excalibur_c2287₁327?Excalibur_c3439₁281?Excalibur_rep_c111263₃07?I AAV4838?Ra_c105310₆60?Ra_c105310₆68?RAC875_c105310₁55?wsnp_Ku_rep_c103889₉0513365 and Ku_c5789₁180. These markers were located on chromosome1 B ?2D?3A?3B?4A?5B?6A?7A and 7B.?3? 3,051 sites were detected at mature period experiments, including 433 stable that were associated with two or more traits. Single markerer loci phenotypic variation ranged from 6.76% to 18.49%.Seven markers were screened to significantly with five or six traits. These six markers were Kukri_c32355₁089 ? wsnp_Ex_c8208₁3870372 ?Excalibur_c23801₁15?Tdurum_contig66604₉2?Kukri_c27662₆45?BS00014126₅1 and RAC875_c34971₁37, which were located on chromosome 2D?3B?5B?6B and 7A.?4? The N utilization efficiency related traits of wheat seedling have significant correlation relationship with agronomic traits at mature stage of wheat. TGW?PH?St WP and TWP were significantly positively related to seedling biomass?N content and N utilization efficiency, GWP was only significantly positively related to SDW?SNC and SNUE.?5? There were two stable markers detected in both seedling and mature period experiments: D_contig74317₅33?5A? and Tdurum_contig47183₂05?1A?, which could be detected in normal N ?low N and high N simultaneously. R2 in the range of 8.19%-14.20%.