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

Wheat（Triticum aestivum） is an important food crops in our country. Soil phosphorus deficiency seriously affects the yield of wheat, while the tolerance to low phosphorus stress in wheat is a complex quantitative trait controlled by multiple genes. It is limited to analyze this trait with traditional quantitative genetics. Making association analysis for wheat P efficiency traits with molecular marker and screening phosphorus efficiency associated marker loci related traits will provide genetic basis reference for wheat breeding. In this study, a variety population was used as the material. Seedling experiments were finished by hydroponics, mature period experiments were carried out in the field. All the population were grown in low phosphate（LP） conditions as a treatment and in normal phosphate（MP） conditions as a control. Effects of phosphorus deficiency on P utilization efficiency at seedling and mature period and final yield were studied. Based on mass molecular marker of SNP, the association analysis of wheat P efficiency-related traits（biomass, P concentration, P absorption and utilization efficiency） and yield-related traits（plant height, spike length, spike, grain weight etc.） were carried on, and some important sites of P nutrition-related traits were detected. The main results are as follows:（1） The change traits of wheat varied under different P conditions. At seedling stage, the root shoot ratio and P utilization efficiency were higher under low level of phosphate, while the accumulative phosphorus amount showed an decrease tendency. This result indicated that the wheat seedlings enhance P uptake by increasing root to shoot ratio and P utilization efficiency to meet the physical needs. However, due to the low concentration of phosphorus in the environment, the cumulative amount of phosphorus was relatively low. At mature period experiments, the plant height, spikelet length, spikelet number per plant, fertile and sterile spikelet number per spike, grain weight per plant and straw weight per plant all decreased under low phosphorus treatment, which demonstrated the biomass output decreasedunder low phosphorus conditions. No obvious difference was observed in grain number per spike and hundred grains weight, indicating that phosphorus deficiency had no significant effect on the progress of starch accumulation in grain.（2） Association analysis showed that 1,485 siteswere detected at seedling experiments, including 288 stable association sites. Among the stable association sites, 198 were associated with two or more traits. Single markerer loci phenotypic variation ranged from 7.5% to 29.92%. Six markers were screened to significantly associated with six or seven traits. These six markers were RAC875_c27273₃34, Tdurum_contig32775₇8, Excalibur_rep_c103109₈ 8, wsnp_Ra_c11232₁8256748, wsnp_Ku_c33028₄2580216 and wsnp_Ra_c5088₉081927. These markers were all located on chromosome 1B.（3） 1,741 sites were detected at mature period experiments, including 249 stable association sites. Among the stable association sites, 172 were associated with two or more traits. Single markerer loci phenotypic variation ranged from 7.45% to 19.75%. Six markers were screened to significantly associated with five or six traits. These six markers were BS00067046₅1（2D）, Kukri_rep_c106786₂30（2D）, RAC875_c34971₁37（7A）, wsnp_Ex_c3 9592₄6849607（5A）, wsnp_Ku_rep_c112734₉5776957（6A） and BS00014126₅1（7A）.（4） Stable markers detected in both seedling and mature period experiments were further analyzed. Tdurum_contig47183₂05（1A） could be detected only in normal conditions, R2 in the range of 8.03%-10.93%. Bob White_c4147₁351, Bob White_c4147₁429, Excalibur_c560 29₂77 and JD_c48840₄51could be detected only in low P conditions. They were located on chromosome 1B with a R2 in the range of 8.22%-12.64%. BS00010131₅1（2D）, BS00078460₅1（7A）, CAP11_c1473₃20（7A）, Ex_c9615₅74（7A）, IAAV1265（7A） and wsnp_Ex_rep_c69123₆8034403（7A） could be detected under normal or low phosphorus conditions, and R2 ranged from 8.02% to 13.11 %.