Development Of Chromosome Segment Introgression Lines From Gossypium Hirsutum Race Punctatum In Gossypium Hirsutum Acc TM-1, The Genetic Standard Line

Upland cotton is the world’s leading cotton cultivars. Upland cotton (Gossypium hirsutum L.) is characterized by high yield and medium fiber quality performance with low genetic diversity and less resistant. Semi-wild species have many favorable genes, such as insect resistance, disease resistance, drought-resistant, high-strength fibers, and so on, The semi-wild species is a valuable resource for cotton genetics and breeding. So, it is important to development the chromosome segment introgression lines from G hirsutum race punctatum in G hirsutum acc TM-1, the genetic standard line. Chromosome segment introgression lines (CSIL) contains a series of near-isogenic lines which covering the entire genome from donor. In each line only one homozygous chromosome segment was transferred from donor parent, the rest of genome are the same as the recipient parent. It is an excellent material for QTL mapping.Based this study, the chromosome segment introgression between G.hirsutum L.and semi-wild species were developed. This could be an ideal material for fining mapping QTL for some the main traits.1. Construction of Genetic frame mapFirst, totally 6208 SSR primers were employed to screen the polymorphisms of the two parental,301 polymorphic SSR primers were obtained. The rate of polymorphism is 4.85%. We used the software Joinmap3.0 to construst linkage group. It produced 451inkage groups in total, containing 248 SSR locis. The full-length was 2467.56cM with the average dstance of 10.67 cM between loci.Using the high density genetic maps of G barbadense and G hirrsutum as a reference, 42 linkage groups were assigned onto 23 chromosomes. The remaining 3 groups were not located on any chromosomes. The coverage of A-subgenomes was 1462.08cM. The coverage of D-subgenomes was 1024.12cM.2 Development of chromosome segment introgression lines from G. hirsutum race punctatum in G. hirsutum acc TM-1, the genetic standard lineIn the present research, we firstly developed one set of CSILs lines. The development of the CSILs lines:the F1 was generated by a cross using TM-1 as the recipient parent and TX-114 as the donor parent. The TM-1 x TX-114 F1 progeny were backcrossed with TM-1 untill BC3 and self-pollinated to produce BC3F2。MAS was conducted to identify the individual of BC3F2.So the chromosome segment introgression between Ghirsutum L.and semi-wild species is built.The CSILs consist of 67 different families which have 505 individuals. The identification was conducted to identify the donor chromosome segments in individuals of BC3F2.There were 1-35donor chromosome segments in the individuals of BC3F2with the average of 12.77. There were 0-10 homozygous donor chromosome segments in the individuals of BC3F2 with the average of 1.72.There were 0-34 homozygous donor chromosome segments in the individuals of BC3F2 with the average of 11.05.zero segment introgression lines have 26 individuals,It mean that the percentage of genetic background was 100%.3. QTLs mapping by backcross population and CSIL populationseven yield components traits including Fruit branch number per plant,boll number per plant, boll weigth, lint percentage,seed index,boll length,boll width and seven fiber quality traits including fiber length, fiber strength, fiber maturity, micronaire, short fiber index, fiber uniformity ratio, fiber elongation were measured from BC3F2 individuals. Marker regression was done by WindowsQTL Cartographer2.5.25 significant makers were detected in the BC3F2 population including 9 significant makers for fiber quality and 16 significant makers for components of yield. Interval mapping was done by WindowsQTL Cartographer2.5.20 significant makers were detected in the BC3F2 population for fiber quality.4. Germplasm enhancementBy investigating the yield and quality traits In the present research, found that some individual of BC3F2 was significantly better than the parental TM-1. The boll weight of 3 individuals reaches 8g; The lint of 3 individuals more than 45%; The fiber length of llindividuals more than 31.0mm with the longest is 32.45; The fiber strength of 7 individuals more than 38.0cN/tex with the max is 39.2 cN/tex. These are excellent new materials, It is important to improved cotton yield and quality traits.