ÃÞ »¨ ѧ ±¨ Cotton Science 2010£¬22£¨5£©£º398-402
Genetic Mapping of Short Fiber Mutant Gene Li2 in Upland Cotton Abstract: Li2 is a short fiber mutant found in the fiber elongation procedure, and the gene that controls short fiber mutant phenotype is named Li2 . Hai7124, developed in China , is a commercial Verticillium -resistant variety in G. barbadense . Sub 18 is a substitution line with G. hirsutum accession £¨acc.£© TM-1 genetic background except that the 18th chromosome (Chr 18) is replaced by the corresponding homozygous chromosome of G. barbadense acc 3-79. In cotton, Li2 gene has been assigned to chr 18 using aneuploid stocks in 2002. The objective of this research was to screen SSR markers tightly linked with Li2 gene by using two F2 segregating populations derived from Li2 mutant and the backbone genetic linkage map from G. hirsutum ¡ÁG. barbadense BC1 newly updated in our laboratory. Genetic analysis suggested that the segregation ratio of short fiber plants in the (Li2 ¡Á Hai7124)F2 fit Mendelian 3¡Ã1 inheritance, confirming that the short fiber trait in Li2 mutant was controlled by an complete dominance gene. However, the segregation ratio of short fiber plants in the (Li2¡Ásub18)F2 did not fit Mendelian 3¡Ã1 inheritance, and this may be related to the temperature-sensitive characteristic of Li2 mutant. Genetic mapping of Li2 was conducted using two F2 populations mentioned above and JoinMap v3.0 software. In the (Li2¡ÁHai7124)F2, Li2 gene was located on the end of chr 18, and the nearest marker Z08 had a genetic distance of 6.051 cM from Li2 . In the (Li2¡Ásub18)F2,Li2 was also located on the end of chr 18, but the nearest marker Z08 was 9.266 cM from Li2.The present mapping of Li2 mutant provides a starting point for fine-scale mapping and positional cloning.
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