Cotton Molecular Markers And Qtl Mapping For Earliness

Precocious cotton is an important resource of cotton in China, it has played an important role in Xinjiang cotton region. Especially in the situation of ensure food security, it is very necessary to develop own production level and improve yield and quality Xinjiang precocious cotton region. That is the theme of production and development of precocious cotton breeding, which improve productivity of short season cotton by means of modern breeding techniques, using molecular breeding techniques combined with conventional breeding, introduce new cotton germplasm resources for high yield and fine quality, to further improve the existing cotton varieties of early maturity, coordinate the contradiction between earliness and fine quality, earliness and high yield.Based on a F2 population from cross between Jin13(Ghirsutum L.)×Hai7124(Gbarbadense L.), a combined SSR genetic map of tetraploid cotton was constructed and QTL mapping was performed. The main results were summarized as follows:1.352 SSR primers from the map of Hai7124 were used to identify polymorphism between two parents, 137 polymorphic SSR primers were obtained. These polymorphic primers were used to analyze genotype of F2 individuals, a total of 143 polymorphic loci were obtained. The 143 polymorphic loci were analyzed by X2 test, 43(30%) loci deviated from the expected ratio (1:2:1 or 3:1).2.143 marker loci were used to construct genetic linkage group using Joinmap3.0. The map consisted of 119 markers mapped into 33 linkage groups, it were assigned to the 26 chromosomes. These linkage groups spanned 1373.7cM with an average genetic distance of 12.9cM per marker. The distance of single linkage group was form 2.4cM to 114.4cM per marker, the loci number in every group was 2 to 16. The longest distance of single linkage group was 114.4cM, mapped in chromosome D8, have 16 loci.3.The earliness traits and some interrelated traits of F2 plants and corresponding F2:3 families were investigated. QTLs were scanned by the method of composite interval mapping(CIM) in program MapQTL5.0, 63 QTLs could be detected. 28 QTLs could be detected in chromosome A and 35 QTLs in chromosome D. To analyze earliness traits of population, 50 QTLs have been detected, 19 QTLs could be detected in chromosome A and 31 QTLs in chromosome D. To analyze antonomic traits including plant height and node of first fruiting branch et, 13 QTLs have been detected, 9 QTLs could be detected in chromosome A and 4 QTLs in chromosome D.4. We used earliness traits of F2 and F2:3 to analyse QTLs, 4 stable QTLs have been discover in detected QTLs. These QTL was listed as follow: qDB-D2-1 whcih detected in chromosome D2, located in loci NAU1529; qBOB-D8-1 whcih detected in chromosome D8, located in loci NAU3201a; qBOB-A1-1 whcih detected in chromosome A1, located in loci NAU591; qDOB-D8-1 whcih detected in chromosome D8, located in loci NAU3201a.