QTL Mapping For Yield Components And Fiber Qualities Using G.Barbadense Chromosome Segment Substitution Lines In Genetic Standard Line G.Hirsutum Acc.TM-1

Cotton(Gossypium spp.)is one of the most important cash crops worldwide due to its excellent natural fiber properties.China is the world's largest producer and consumer of textiles.Upland and Sea Island cotton are two cultivated tetraploid cotton varieties.Upland cotton(Gossypium hirsutum L.)is characterized by high yield and moderate fiber quality performance.Sea Island cotton(G.barbadense L.)is characterized by low yield,increased fiber fineness and strength.Intraspecific narrow genetic base has been a main problem for genetic improvement of Gossypium hirsutum L.Introgressing the elite genes from G.barbadense into G.hirsutum is one of the most important avenues for breeders to broaden Upland cotton's genetic base.In the previous researches,by using the technology of backcrosss and marker-assisted selection,Sea Island cotton chromosome segment introgression lines(CSILs)in background of genetic standard line of Upland cotton TM-1 have been developed.In this study,three CSILs were selected with dramatically different yield and fiber quality compared to the recipient parent TM-1.These three CSIL lines were crossed with TM-1 to produce F1 progeny,were backcrossed with TM-1 to produce F2 population.Molecular markers of SSR were used to analysis and map the QTL in lint percent and fiber quality.Among these three CSILs,IL-009 is highly significant superior than the TM-1 in lint percent,fiber length and fiber strength.IL-058 is highly significant better than the TM-1 in lint percent,but it is dramatically smaller than the TM-1 in boll weight.However,IL-061 is dramatically worse than the TM-1 in boll weight and lint percent,but superior than the TM-1 in fiber length.Based on scaning whole-genome SSR marker,the introgressed G.barbadense segments in IL-009 were identified on 6 chromosomes,including A3,A5,A7,D2,D9 and D10.The introgressed segments in IL-058 were identified on 5 chromosomes,including A12,D5,D8,D10 and D11.The introgressed segments in IL-061 were identified on A5 and D2.In the(IL-009�TM-1)F2 population,one QTL for lint percent was identified between 0.0-15.9 cM on D9,which explained 6.2%of the phenotypic variance.Another QTL for fiber strength was detected between 0.0-13.3cM on D9,which explained 1.9%of the phenotypic variance.In(IL-058�TM-1)F2 population,only one QTL for lint percent was detected between 14.8-35.6cM on D8,which explained 1.7%of the phenotypic variance.In(IL-061�TM-1)F2 population,the QTL for boll weight was detected between 4.0-12.4cM on D2,which explained 23.2%of the phenotypic variance.One QTL for lint percent was detected between 6.0-12.9cM on D2,which explained 19.4%of the phenotypic variance.One QTL for seed index was detected between 0.0-4.4cM on A5,which explained 14.5%of the phenotypic variance.Additionally,one QTL for micronaire was detected between 3.1-12.3cM on D2,which explained 10%of the phenotypic variance.