Assessing the Potential of Sealand Lines for Fiber Quality Improvement of Upland Cotton (G. hirsutum)

Germplasm lines are an important resource for plant breeders targeting novel alleles from wild or unadapted relatives to improve elite germplasm. In Upland cotton (Gossypium hirsutum L.), historical records suggested that several obsolete germplasm lines with excellent fiber quality may have been derived via interspecific introgression; however the effective utilization of such lines in marker assisted breeding rests on the ability to target and exploit segments harboring favorable alleles. The objective of this study is to identify and evaluate the effects of alien chromosomal segments in the G. barbadense introgressed lines Sealand-542 & Sealand-883. F2 mapping populations were developed by crossing the Sealand lines with Upland cotton lines representing major types of genetic backgrounds of the US cotton. Out of 1200 SSR markers screened, 139 (11.6%) were polymorphic between the Sealand lines and genetic background parents. Many of the markers were tightly clustered on seven of the thirteen At/Dt homeologus chromosomes, suggesting that these were introgressed segments from the donor genomes. QTL analysis revealed that a number of the identified introgressed regions harbored positive alleles for fiber quality traits, however the percent phenotypic variation explained varied across different genetic backgrounds.