| Cotton is an important economic crop, especially for textile industry.Upland cotton (Gossypium hirsutum) is the most widely cultivated in China which exhibits high fiber yield but only moderate performance of fiber quality; G. barbadense is characterized by fine, strong fibers, resistance to verticillium wilt and low fiber yield. It is a promising approach to enlarge the narrow genetic base of Ghirsutum that introgress the valuable traits and genes to G. hirsutum from G. barbadensefor synchronous improvement of cotton fiber yield and fiber quality. In this study, chromosome segment substitution lines were developed using G. barbadense var. Hai1as the donor parent and Gossypium hirsutum var. CCRI36as the recipient parent. BC5F3, BC5F34and BC5F35were planted in Anyang, Henan in2009,2010, and2011, respectively, and BC5F35in Liaoyang, Liaoning and Shihezi, Xinjiang in2011.224SSR markers were selected from14chromosomes in a linkage map constructed earlier, which were used to assess the408BC5F3individuals and identify the QTLs related to fiber yield and quality-related traits, these stable QTLs are used for fine QTL mapping, gene cloning and the marker assisted selection.1.224SSR markers from14chromosomes were used to assess the408BC5F3individuals, the total chromosome segments length covered2339.1cM, the chromosome substitution rate of the recurrent parent in the BC5F3individuals was from85.5%to100%, the average rate was97.3%. The average length of chromosome segments of Gossypium barbadense in BC5F3individuals was62.2cM and ranged from2.3cM to339.2cM, the average percentage of chromosome segments of Gossypium barbadense in tested length is2.6%; the average length of homozygous Gossypium barbadense chromosome substitution segments is38.4cM and ranged from2.3cM to226.9cM, which covered1.6%of the tested length; the average length of heterozygous Gossypium barbadense chromosome substitution segments is23.8cM and ranged from2.3cM to184.8cM, the average percentage of chromosome segments of Gossypium barbadense in tested length is1.0%. There are15plants detected no chromosome substitution segments of Gossypium barbadense in408BC5F3individuals;47plants contained the single chromosome substitution segments of Gossypium barbadense, of which39plants contained one homozygous donor chromosome segments;60plants contained two chromosome substitution segments of Gossypium barbadense, of which32plants contained two homozygous donor chromosome segments;60plants contained three chromosome substitution segments of Gossypium barbadense;226plants contained four or more donor chromosome segments.2. QTL IciMapping V3.2was used to detect QTL for fiber yield and quality-related traits in chromosome segment substitution lines (BC5F3, BC5F34and BC5F35),70QTL for fiber yield related-traits and29QTL for fiber quality-related traits were detected, which were mapped on13chromosomes, and each QTL account for2.57%-23.07%of phenotypic variance.35QTLs were detected in at least two environments,19QTL (1for fiber strength and fiber uniformity, respectively;2for lint percent, seed index and fiber micronaire respectively;3for plant height;4for bolls per plant and fiber length, respectively) were detected in two environments;7QTL (1for bolls per plant and seed index, respectively;2for plant height;3for fiber length) were detected in three environments;6QTL (1for plant height,2for seed index and3for fiber micronaire) were detected in four environments;3QTLs for lint percent were detected in five environments. These stable QTLs are used for the marker assisted selection.3、SSR markers were used to assess the BC5F3individuals, BC5F34lines and BC5F35strains.10plants were screened with1-13chromosome segments of Gossypium barbadense, most of them have fiber strength above30cN/tex and fiber length above30mm. These CSSLs are useful for selecting SSSLs and fine maping QTL for fiber quality. |
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