Phenotype Evaluation And Molecular Marker Excavation For Drought Resistance Of Upland Cotton

Cotton is one of the most important economic crops in China.Drought has always been a key factor restricting the development of cotton production.In this study,a natural population of upland cotton consisting of 191 cultivars was used as experimental materials.Measure related indicators at germination stage and flowering and boll-setting stage under drought tolerance.A total of 74 pairs of simple sequence repeat(SSR)primers were employed to detect the genomic variation of the natural population,in order to lay the foundation for cotton drought tolerance molecular assisted selection breeding.1.In this study,seven agronomic traits and five fiber quality traits were studied in the period of flowering and boll-setting stage,mainly using drought resistance comprehensive evaluation values,combining with comprehensive drought resistance coefficient and drought resistance index to comprehensive evaluation of drought resistance of 191 materials.Seven materials with drought resistance,i.e.Xinluzhong 36,ZZS-34,ZZS-41,SGK321,30741,ZZS-18,Guoxinmian11,were screening out.2.The polymorphism of the natural population was scanned by using 74 pairs of primers,147 polymorphic loci were found,involved 246 alleles,with allelic variation of 2 to 7;By using population structure analysis method,the 191 materials may be divided into two subgroups,which consistsof 123 and 68 members,respectively.3.In the germination stage,MLM(Mixed linear model)was used to analyze the germination rate,comprehensive drought resistance coefficient and drought resistance comprehensive evaluation values,35 loci were detected under P<0.05,and 15 loci were detected when P <0.01.Six loci,i.e.NAU3017-1,NAU3468-2,NAU5233-1,SWU10214-2,NAU5351-2,and NAU3096-2,were detected,which were significantly correlated with the drought resistance comprehensive evaluation values and drought resistance coefficient;Four loci,i.e.BNL3452-1,NAU3419-1,NAU2265-1 and BNL3469-1 were significantly correlated with the drought resistance comprehensive evaluation values and the germination rate.4.In the flowering and boll-setting stage,12 phenotypic traits,drought resistance comprehensive evaluation values,comprehensive drought resistance coefficient and drought resistance index were analyzed by MLM.While P<0.05,122 loci were detected associated with drought resistance traits.27 marker loci are found associated with two or more phenotypic traits;NAU5163-1 could be detected simultaneously under three indicators;NAU3424-2 was found associated with comprehensive drought resistance coefficient and drought resistance index;Six loci were detected associated with drought resistance comprehensive evaluation values and drought resistant traits,i.e,NAU5064-2,NAU980-1,NAU5064-1,NAU980-2,NAU2980-2,and NAU5428;Five loci were detected associated with drought resistance index and drought resistant traits,respectively,which are NAU3017-2,NAU3468-1,NAU4042-1,SWU10054-2,and SWU10056-1.