Abstract:

Sub-red mutant, used as a female parent, was crossed with GK19 to generate F₁ plants, which surpassed their parents with its good photosynthesis efficiency. In this sense, sub-red mutant would be regarded as a potentially elite germplasm. Molecular markers linked to sub-red mutant gene are of great importance for fine mapping the sub-red gene and cloning. To screen for SSR markers closely linked to sub-red gene in upland cotton, we developed the F₁ and BC₁ from intraspecific crosses with the parents mentioned above. Screening of 419 SSR markers, covering all the identified chromosomes and most linkage groups of cotton, was performed by bulked segregation analysis, revealing informative SSRs, mapped on the above populations afterwards. One co-dominant SSR marker BNL2634 was identified closely linked to the sub-red gene (tentatively named as Rs), with an estimated distance of 10.3 cM, depending on the population used. The other five markers linked to Rs were CIR393, with a loose linkage to Rs (approximately 29.1 cM), CIR335, BNL1597, NAU1362, and NAU1048, showing the Rs gene to be located on cotton chromosome 7.

Key words: Upland cotton, Sub-red mutant, Gene location, SSR