Simple sequence repeat (SSR) markers linked to the Ligon lintless (Li1) mutant in cotton

Ligon lintless (Li1) is a monogenic, dominant mutant in cotton, whose expression results in extreme reductions in fiber length on mature seed. The objectives of this research were to compare fiber initiation between the Li1 mutant and TM-1 to reveal the fiber initiation differences between normal and mutant phenotypes, to develop a linkage map of simple sequence repeat (SSR) markers with the Li1 locus, and to identify the chromosomal location of the Li1 locus. Comparative scanning electron microscopy studies of fiber development in a normal TM-1 genotype and the near-isogenic Li1 mutant at 1 and 3 days postanthesis revealed little differences between the two during early stages of development, suggesting that Li1 gene expression occurs later, probably during the elongation phase. Thirty-eight SSR loci were found to be polymorphic between TM-1 and Li1 and were used for mapping in an F2 population. Twenty-two SSR loci, along with Li1, were located on eight linkage groups, covering a total genetic distance of 218.3 cM. Analysis of individual monosomic and monotelodisomic plants indicated that two SSR loci (MP4030 and MP673) from the Li1 linkage group were located on chromosome 22.