Identification of Robust Microsatellite Markers for Fiber Length in Gossypium Spp

One challenge that breeders face concerning the improvement of fiber quality traits is low genetic diversity among elite, agronomically acceptable genotypes of G. hirsutum. The use of marker-assisted selection (MAS) could help breeders access unexploited genetic diversity as well as decrease the cost of phenotyping for fiber quality traits. Linkage (bi-parental) and association mapping studies have led to the discovery of hundreds of quantitative trait loci (QLT) for fiber length and strength, and many of these QTL detected show promise for use in MAS. However, there are few reports of public programs utilizing MAS for the improvement of fiber quality traits. Generally, there has been a lack of consistency among fiber quality QTL detected across studies, which is attributable to many different factors, including experimental error, QTL by environment interactions, and QTL by genetic background interactions. Though more recently, several association studies and meta-analyses have helped identify stable QTL and important chromosomal regions for fiber quality traits. Identifying tightly linked markers to robust fiber quality QTL is important to the efficiency and use of MAS. The objectives of this study were to assess the effects of previously reported microsatellite markers (SSRs) for fiber length and strength in three different genetic backgrounds and identify robust and portable SSRs for use in MAS for fiber quality. Two intra-specific populations (G. hirsutum x G. hirsutum) and one inter-specific population (G. hirsutum x G. tomentosum/G. mustelinum) were selected for the study based on high levels of polymorphism. Within the three selected families, 285 individual F_2:3 plants were genotyped for approximately 250 SSRs, hand harvested, and sent for high volume instrument (HVI) analysis of fiber quality traits. These data will be used to identify robust candidate markers and evaluate their utility in MAS for fiber quality among the TAMU breeding program populations.