Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/5/1997
Publication Date: N/A
Technical Abstract: Cultivated cotton, G. hirsutum L. & G. barbadense L., is the leading natural fiber crop. Inheritance of cotton fiber strength, as measured by fiber bundles, displays additive quantitative nature. Classical cotton breeding has had success in improving fiber strength through the tedious process of selection based on measuring fiber strength in advance generation of the selected lines. Molecular markers in cotton create unprecedented opportunities to improve competition of US cotton production by targeting genetic changes and accelerating breeding progress. We are currently identifying DNA markers linked to fiber strength and other traits (Glandless, Photoperiod sensitivity, immature fiber, and Ligon lintless-2) in cotton. F2 progeny from an interspecific cross between two commercially important cottons, G. hirsutum L. acc. TM-1 and G. barbadense L. acc. 3-79, were used to construct the molecular map and to determine the location of QTLs for fiber strength and other fiber quality properties. Hundreds of DNA markers (RAPDs, RFLPs, AFLPs, and SSRs) have been generated and their segregations have been determined among 152 F2 individuals of TM-1 X 3-79. A framework map was constructed (141 RAPDs and 62 RFLPs in 28 linkage groups). About half the groups were assigned to the cotton chromosomes by use of substitutional aneuploid cottons. Three putative QTLs for fiber strength were detected among the 28 linkage groups. Mapping of monogenic traits are underway by use of respective crosses segregating for these genes. Two dominant genes, glandless & photoperiod sensitivity, were mapped to different linkage groups via DNA markers at about 25-30 cM. Tighter linkages of these genes to additional DNA markers will provide a valuable tool for revealing the genetic basis and improving cotton.