| Cotton is an important oil and economic crop,and it is also an important source of textile fibers in the world.Cotton growth is often affected by abiotic stress,especially drought stress,leading to reduced yields and even death of cotton plants.The Blossing and Boll-forming Stages is the most critical period for cotton growth and water and fertilizer requirements.This period of water shortage will have a significant impact on cotton yield and quality.Cotton Upland-island Recombination Inbred Line population is a group that has both the excellent yield characteristics and extensive adaptability of Upland cotton,and the excellent fiber quality of Island cotton.In this study,the F2:6 Upland-island Recombination Inbred Line population constructed with the drought resistant Upland cotton material zhong07 as the female parent and the drought sensitive Island cotton material Xinhai 20 as the male parent was used as the experimental material.The drought stress treatment was carried out at the Blossing and Boll-forming Stages,and the drought resistance of the population material was identified.The extreme materials in the population were analyzed by BSA method,and the candidate genes related to drought resistance were mined.It provides the basis for the study of drought resistance ability and drought resistance genes of cotton in the future.The main results are as follows:(1)Based on the correlation analysis,there was a stable and strong cooperative change trend among the traits to drought stress,in terms of agronomic characters,Plant height(PH)vs Fruit branch number(FBN),Fruit branch number(FBN)vs Effective fruit branch number(EFBN),Boll number(BN)vs Effective boll number(EBN)vs Effective fruit branch number(EFBN),Boll number(BN)vs Effective boll number(EBN),Cotton seed yield(CSY)vs Cotton lint yield(CLY)vs Single boll weight(SBW),Cotton seed yield(CSY)vs Cotton lint yield(CLY),Cotton lint yield(CLY)vs Lint percentage(LP),in terms of physiological aspect,Chlorophyll b(Chl-b)vs Chlorophyll total(Chl-t)vs Chlorophyll a(Chl-a),Chlorophyll b(Chl-b)vs Chlorophyll total(Chl-t),Superoxide dismutase(SOD)vs Peroxidase(POD).there was a stable and strong antagonistic trend among the traits to drought stress,in terms of photosynthetic characters,Net photosynthetic rate(A)vs Intercellular carbon dioxide concentration(Ci)vs Vapor pressure deficit(VPD),Water use efficiency(WUE)vs Intercellular carbon dioxide concentration(Ci)vs Vapor pressure deficit(VPD),Transpiration rate(E)vs Vapor pressure deficit(VPD),Intercellular carbon dioxide concentration(Ci)vs Vapor pressure deficit(VPD).(2)Based on the principal component analysis,the changes of Plant height(PH),Boll number(BN),Effective boll number(EBN),Cotton seed yield(CSY),Cotton lint yield(CLY)and Lint percentage(LP)in agronomic characters,Net photosynthetic rate(A),Transpiration rate(E),Water use efficiency(WUE),Intercellular carbon dioxide concentration(Ci)and gs in photosynthesis,Chlorophyll(Chl),Malondialdehyde(MDA),Superoxide dismutase(SOD)and Peroxidase(POD)in physiological and biochemical aspects were more obvious under drought stress.(3)The drought resistance grade is classified by the method of system clustering.In terms of agronomic traits,Shawan and Kuitun were divided into four groups,which were respectively strong drought resistance type,medium drought resistance type,drought resistance type and drought sensitive groups.In the two regions,zhong07 was divided into drought resistant groups,Xinhai 20 was divided into drought sensitive type groups,There were 9 copies of the population materials that were drought sensitive and 8 copies of the population materials showed drought resistance In terms of photosynthetic characters,Shawan and Kuitun were divided into five groups,which were strong drought resistance type,medium drought resistance type,drought resistance type,drought sensitive type and drought extremely sensitive type.In the two regions,Zhong07 was divided into the medium drought resistant groups and Xinhai20 was divided into the drought sensitive groups.there were 9 materials that were sensitive or extremely sensitive to drought,5 materials that showed drought resistance and 4 materials that showed medium drought or strong drought resistance.In physiological,Shawan was divided into four drought resistant groups,which were strong drought resistant type,medium drought resistant type,drought resistant type and drought sensitive type.Kuitun was divided into five groups,which were strong drought resistance type,medium drought resistance type,drought resistance type,drought sensitive type and drought extremely sensitive type.In the two regions,Zhong07 was divided into the medium drought resistant group and Xinhai20 was divided into the drought sensitive group.At the same time,in both regions,there were 12 drought resistant materials and 8 drought resistant or strong drought resistant materials.(4)Select drought-resistant materials and drought-sensitive matrials based on agronomic and yield traits to construct drought resistance pool and sensitive pool respectively.By using BSA sequencing technology,the genes controlling drought resistance of cotton were initially located in four related candidate regions,with a total length of 21.98 Mb and 1000 genes annotated in the related regions.According to the annotation results of GO database,106 genes involved in the regulation of drought resistance and 44 genes related to drought stress were predicted. |
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