Linghe Zeng, USDA-ARS, Crop Genetics and Production Unit. USDA ARS, 141 Experiment Station Rd, Stoneville, MS 38776 and William Meredith, Delta States Res. Ctr., 113 Bayou Oaks Circle, Greenville, MS 38701.
Genetic improvement in fiber quality is needed for U.S.A. cotton in order to meet the needs of modern textile processing and international competition. A random mated population derived from multiple crosses among tetraploid species, designated as Species Polycross (SP), was used in this study to identify SSR markers associated with yield components and fiber traits. Two hundred and sixty inbred lines of this population were grown in a randomized complete block design at two locations with two replicates each in summer 2005. Genotypic variation was highly significant (p<0.001) for all traits analyzed in the population. Two hundred and three lines in this population have been genotyped as of yet. A total of 95 primer pairs were screened and 77 were polymorphic in the population. The number of alleles per primer pair ranged from 2 to 8. A total of 257 fragments were scored among the lines. Polymorphic Information Content (PIC) ranged from 0.112 to 0.796 with average of 0.395 among the polymorphic primers. For each of the yield components including lint percentage, boll weight, seed weight, seeds per boll, and lint per seed, 5 to 9 significantly (p<0.01) associated fragments were identified. For each of the fiber properties including strength, length (50%), length (2.5%), micronaire, elongation, and short fiber content, 5 to 16 significantly (p<0.01) associated fragments were identified. For example, markers associated with boll weight at p=2x10-10 and r2=0.18 and elongation at p=7x10-6 and r2=0.10 were identified.