Fine mapping of the red plant gene R 1 in upland cotton(Gossypium hirsutum)

Sub 16 is a substitution line with G. hirsutum cv. TM-1 genetic background except that the 16th chromosome (Chr. 16) is replaced by the corresponding homozygous chromosome of G. barbadense cv. 3-79, and T586 is a G. hirsutum multiple gene marker line with 8 dominant mutation genes. The R (1) gene for anthocyanin pigmentation was tagged in Chr. 16 in T586. The objective of this research was to screen SSR markers tightly linked with R (1) by using the F-2 segregating population containing 1259 plants derived from the cross of Sub 16 and T586 and the backbone genetic linkage map from G. hirsutumxG. barbadense BC1 newly updated by our laboratory. Genetic analysis suggested that the segregation ratio of red plants in the F-2 population fit Mendelian 1:2:1 inheritance, confirming that the red plant trait was controlled by an incomplete dominance gene. Preliminary mapping of R (1) was conducted using 237 randomLy selected F-2 individuals and JoinMap v3.0 software. Then, a fine map of R1 was constructed using the F-2 segregating population containing 1259 plants, and R (1) was located between NAU4956 and NAU6752, with only 0.49 cM to the nearest maker loci (NAU6752). These results provided a foundation for map-based cloning of R (1) and further development of cotton cultivars with red fibers by transgenic technology.