QTL Mapping Of Wheat Biomass In Seedling And After Blooming Under Drought Condition And Selection Of Drought Resistance Germplasm

Wheat is one of the major food crops in the world. To achieve the high yield of wheat was breeder's constant pursue goal. Production of wheat are divided into economic yield and biological yield,and wheat harvest index has been close to the highest value after many years of directional selection.Therefore, improving biomass per unit area of wheat and coordinating the relationship between biological and economic yields of wheat are effective means to achieve the final yield of wheat. The planting area of wheat in our country is stable at about 24 million hectares, among them, about 6 million hectaresare dryland wheat.One RIL population?F8:9? contains173 lines derived from a cross of common wheat Shannong01-35 and Gaocheng9411 was used in the study. Seven wheat seedling related traits were analyzed in the mode of simulated water stress with PEG-600. QTL mapping for biomass of wheat after anthesis were conducted under rainfed and well-watered conditions using high density SNP genetic map. The germination rate and related traits at seedling stage of 205 accessions of wheat germplasm resources was tested under-0.5MPa PEG-6000 concentrations. The whole period of wheat was tested under rainfed and well-watered conditions. The main results were as follows:1. A total of 30 additive QTLs were detected for shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, height, total root length, fresh weight of root to shoot ratio traits under different concentrations of PEG-6000 treatment at wheat seedling, which distributed on chromosome1 A,1B, 1D, 2D, 3B, 4B, 5A, 6B, 7B. Among them, QTL4 B.4-13 were detected related with the shoot fresh weight, shoot dry weight, and root fresh weight and root dry weight, with 12.12%-19.59% of phenotypic variation explaination. QTL1 A.1-5 controlling root fresh weight and root length with 6.80%-8.02% of phenotypic variation explaination. One pair of epistatic QTL for the shoot dry weight, root fresh weight, shoot height, root length were detected.2. A total of 73 additive QTLs were detected for biomass of wheat after blooming under the two environments in different sampling time. Among them, QTL4 B.4-17?EX_C101685₇05-RAC875_C27536₆11? was detected under two environments in different sampling time with 20% or more of phenotypic variation explaination. QTL6 A.2-312 was repeatedly detected for single stem flag leaf dry weight and dry weight of a single piece of leaf traits with 9.37%-11.91% of phenotypic variation explaination. 7A.11-24 was detected for single stem dry weight, dry weight per stem stalk traits under different environments and different sampling time.Total of 31 additive QTLs for wheat after blooming related traits of stem biomass were detected had interaction with environment. Among them, QSTW4 B.4-17 was repeatedly detectedin 9 days, 27 days and 36 days after blooming, and had interaction with the environment.3. Two additive QTLs were detected for the leaf area in 9 days and 18 days after blooming of wheat, of which, QTL 7A.9-4 with 17.52% of phenotypic variation explaination. At the jointing stage and grain filling stage, 8 QTL were detected to control the chlorophyll content of wheat at the top of wheat. Among them, QTL 4B.4-13 was repeatedly detected at the two periods with 12.79%-18.83% of phenotypic variation explaination.4. Drought resistance identification was conducted for 205 wheat varieties?lines? during the period of germination, seedling stage and whole growth stage of wheat. As a result, 11, 26, 15 strong drought resistance varieties?lines?were selected, respectively, of which five materials?Wen Hang 1 Hao, Shi 4185, Xuzhou 24, Heng 5229 and W110149? were identified with strong or strongdrought resistance using two or above methods.