Submitted to: World Cotton Research Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 1, 1998
Publication Date: N/A
Interpretive Summary: Plant breeders are primarily involved in improving complex quantitative traits (QTL) that are controlled by many genes. Molecular markers linked to QTL will help breeders to monitor the hereditary materials associated with the QTL. Recently our research unit reported a linkage map of a class of molecular markers called Restriction Fragment Length Polymorphism (RFLP) and QTL using a second-generation (F2) population of improved upland cotton cultivars. The objective of this paper is to identify the chromosomal location of some of the RFLP and QTL linkage map that our unit reported. We have identified chromosomal location of several RFLP and QTL linkage groups. We observed that about 25 QTL, associated with economically important fiber characteristics were located on A genome-specific chromosomes and 13 fiber-related QTL genes were located on D genome-specific chromosomes. Our results also showed that 5 of the 13 A genome-specific chromosomes and 2 of the 13 D genome-specific chromosomes of upland cotton (AD genome) were associated with fiber-specific QTLs. Our results indicate that A genome diploid species may be a useful source for improving some of the QTLs in upland cotton. The molecular map linked to QTL of specific chromosome regions will be useful in germplasm introgression and map based cloning of important genes.
Technical Abstract: Recently, Shappley et al. (1998) reported a linkage map of RFLP markers and quantitative trait loci (QTL) in an intraspecific F2 population of upland cotton. The overall objective of this paper is to identify the chromosomal location of some of the QTL and RFLP linkage groups that Shappley et al. (1998) discovered using some of their linkage-specific RFLP probes. The genomic DNAs from an inbred G. hirsutum cv. Texas Marker (TM1) and inbred G. barbadense cv. Pima 3-79 were used as standards to compare with the genomic DNAs of monosomic F1 and monotelodisomic F1 chromosome substitution lines developed from interspecific crosses between TM1 and Pima 3-79. The deletion analysis of the cytogenetic deficient F1 stocks indicated that the linkage group (LG) 15, LG 26, and LG 30 were located on the long arm of chromosome 26. The deletion analysis also showed that the LG 20 was located on chromosome 4. The LG 12 was located on chromosome 12. The LG 21 was located on chromosome 10. The LG 17 was assigned to chromosome 9. Results also indicated the LG 14, the LG 19, the LG 18, and the LG 29 were located on chromosome 3. We observed that about 25 QTL loci, associated with fiber characteristics, including elongation, maturity, fiber wall thickness and seed index, were located on A genome-specific chromosomes and 13 fiber-related QTL loci were located on D genome-specific chromosomes of the tetraploid species (AD genome).