Enrichment Of The Genetic Linkage Map Of Upland Cotton (G.hirsutum) And Comparative Mapping With The Interspecific Map Derived From G.hirsutum And G.barbadense

Using molecular marker technology, high-density molecular marker linkage map can be constructed, which is helpful to explore the correlation between molecular markers linkage groups and chromosomes, to locate QTLs for the important quality and quantity traits, to conduct marker-assisted selection in cotton breeding and map-based cloning.Now, more interspecific linkage maps have been constructed, but only less and the intraspecific linkage maps less. Compared to intraspecific population, the genetic polymorphism of interpecific population was at the molecular higher, and the segregation distortion higher, too. The segregation distortion influences the true distance of the recombinationorganization of inter-markers. Therefore, it is be most desirable to constructe and analyze the molecular genetic linkage map of Upland cotton for targeted traits. Now the situation of the molecular genetic map of intraspecific of Upland cotton is: fewer markers, low map coverage, of course, it is far less than the needs for molecular marker-assisted selection （MAS）. Therefore, it is greatly significance to build high-density intraspecific molecular genetic map of Upland cotton.In this study, the intraspecific F₂ population derived from DH962 and Jimian5 including 137 plants in our laboratory was selected to construct a higher dense linkage map of G. hirsutum by application of newly developed SSR markers, and companion between the intraspecific map and our previous interspecific map was also conducted.Three sets of SSRs including 3479 pairs of HAU, 699 pairs of NAU, 700 pairs of Gh, totally 4878 SSR markers were used to screen polymorphism between DH962 and Jimian5. One hundred seventy six （3.61%） pairs of polymorphic markers were obtained and 183 polymorphic loci in F₂ population.The molecular map was onstrected using Joinmap 3.0 program （LOD scores≥4.0, recombination frequency≤40.0cM）, and 158 markers in this study were mapped into 42 linkage groups which were assigned to 23 chromosomes. The locus number of every linkage group was from 1 to 15. Through the overall mapping, assigning 638 polymorphic markers, obtaining 47 linkage groups. Of these, 35 linkage groups were assigned to corresponding 23 chromosomes. This map spaned 2331.6 cM with approximately 50.03% of the recombination length of cotton genome, the average distance between loci was 3.8 cM.Siginificant segregation distortion was obserbed for 34 locus （18.58%）, 26 were co-dominant and 8 dominant. There were 11 locus skewed toward the heterozygote, 11 locus toward DH962, 12 locus toward Jimian 5. seven ones located on chromosome23 （C23）.Comparative mapping between intraspecific map and interspecific map was conducted. Seventeen （36.2%） linkages in the intraspecific map and 18 （40.9%） linkages in the interspecific map were included, and coverd 15 chromosomes; 33 loci were common between the two maps, and there were 1～3 loci in every chromosome. The order of cir043, bnl946 and bnl3948 in the chromosome20 was different between the two maps, and the others were in the same order between the two maps.