Studies On The Moleular Markers Of The Gene Of Verticillium Wilt Resistance In Gossypium Barbadense

The research on the resistance identification, molecular markers and cloning of the markers linked with Verticillium wilt resistance gene were carried out by using the interspecific cross between Ghirsutum×Gbarbadense. The objectives were to search and clone the molecular markers linked with the resistance gene. This would lay a foundation for cloning the resistance gene and for molecular marker-assisted selection(MAS) of breeding resistant variety. The main results were as follows:1 .Analysis of resistance of Verticillium dahliae by F₂ population and F₂:3 family of susceptible Ghirsutum. variety CCRI 8 × resistant Gbarbadense variety Pima90-53 indicated that among the F₂ individuals and the F₂ individuals identified from the F₂:3 family, the resistant individuals:the susceptible individuals accorded with 3:1 and it accorded with the x_C² test.2.Seven hundred and sixty-eight pairs of SSR primers were amplified between the resistant and susceptible gene pools of the F₂ cross of CCRI 8×Pima90-53 which had one hundred and eighty-two individuals. Out of the primers, BNL3255 and BNL2440 showed polymorphism between gene pools and the parents also had the same polymorphic markers on the same locus. A polymorphic fragment of 208 bp amplified by BNL3255 primer was designated as BNL3255-208. The PCR results amplified by the two SSR primers of these F₂ individuals were analyzed by using MAPMAKER/EXP(VERTION 3.0b) software. The results indicated that BNL3255-208 linked with the gene of G barbadense Verticillium wilt resistance and the genetic distance between them was 13.7 cM. The polymorphic markers amplified by BNL2440 did not linked with the resistant gene. Three hundred and fifty-six pairs of AFLP primers were amplified between the resistant and susceptible gene pools of this F₂ cross. There were not polymorphic AFLP primers between gene pools.3.The application value of BNL3255-208 was validated by two F₂ crosses of CCRI8 X Pima90-53. One of them had two hundred and fifteen individuals and another had one hundred individuals. The result was that most of the resistant plants had BNL3255-208 and it can be used in marker-assisted selection (MAS) and the practice of breeding.4.The polymophic fragment of 208 bp amplified by BNL3255 primer and related with resistant gene was recovered by the method of gene engineering. By connecting, transforming, cloning, detecting its sequence, a marker of 211bp-long, including 10 times TG repeats was found. This marker can be used in filtering bacterial artificialchromosome(BAC) library, isolating and cloning Verticillium wilt gene.