QTL Analysis of Cotton Fiber Quality Using MultipleGossypium hirsutum×Gossypium barbadenseBackcross Generations

Abstract

Cotton fiber properties are essential predictors of yarn performance. The suite of fiber quality traits that collectively affect the utility of the fiber for the textile industry include the length, the strength, the fineness and the color. These properties have been shown to be moderately to highly heritable. In an attempt to overcome the limitations of conventional breeding we undertook a marker‐assisted selection program aimed at introgressing fiber quality QTLs from Gossypium barbadense L. into G. hirsutum L. We describe the QTL analysis of 11 fiber properties measured on three phenotypic data sets. The three populations studied were the 1st (BC1) and 2nd (BC2 and BC2S1) backcross generations derived from the cross between ‘Guazuncho 2’, G. hirsutum, and ‘VH8’, G. barbadense Collectively we detected 80 QTLs, of which 50 surpassed the permutation‐based LOD thresholds (3.2–5.7). The most economically important traits, length (two correlated properties), strength, fineness (four properties), and color (two properties) were influenced by 15, 12, 21, and 16 QTLs, respectively, that could be detected in one or more populations. As expected, for the majority of QTLs, the favorable alleles came from the G. barbadense parent. Altogether one third (26) of the QTLs confirmed the map position and phenotypic effect of QTLs reported in the literature also detected in interspecific G. hirsutum × G. barbadense populations. Cases of colocalization of QTLs for different traits were more frequent than isolated positioning. Taking these QTL‐rich chromosomal regions into consideration, 19 regions on 15 different chromosomes, were identified as target regions for the marker‐assisted introgression strategy.

Construction of a linkage map and QTL mapping for fiber quality traits in upland cotton (Gossypium hirsutum L.)

“…Here we found many common characteristics of QTLs related to fiber quality traits as described in the previous reports involving interspecific maps [3,10,23,[33][34][35][36][37][38] and intraspecific maps [12,15,26,30,[39][40][41][42][43][44][45][46], although few common markers were used in the present research and the previous studies, and the maps covered different region parts of cotton genome, making it difficult to compare the common QTLs, some QTLs were detected and mapped on the same chromosomes and affect common traits. These include seven QTLs for fiber length located in the same chromosomal regions as reported earlier [10,26,34,41,42], two QTLs for fiber uniformity ratio located in the same chromosomal regions [43,46], two QTLs for fiber micronaire [10,43,44], three QTLs for fiber elongation [30,36,42,43,46,47], and 4 QTLs for fiber strength [26,34,36,43,44,46,47].…”

“…These include seven QTLs for fiber length located in the same chromosomal regions as reported earlier [10,26,34,41,42], two QTLs for fiber uniformity ratio located in the same chromosomal regions [43,46], two QTLs for fiber micronaire [10,43,44], three QTLs for fiber elongation [30,36,42,43,46,47], and 4 QTLs for fiber strength [26,34,36,43,44,46,47]. For example, the chromosome regions where QTLs were detected for fiber length in our research matched those in an interspecific map developed from an F 2 population [10]; the QTLs may be common QTLs for fiber quality traits.…”

Toward Sequencing Cotton (Gossypium) Genomes: Figure 1.

“…Linkage maps in tetraploid cotton have been most densely populated by analysis of interspecific G. hirsutum 3 G. barbadense F 2 families (Reinisch et al, 1994;Rong et al, 2004) and backcross lines (Lacape et al, 2005;Guo et al, 2007) due to low levels of DNA polymorphism within cotton species. Mapping populations have also been developed for G. hirsutum 3 Gossypium tomentosum F 2 and Gossypium mustelinum 3 G. hirsutum (P. Chee and A. Paterson, unpublished data).…”

Effects of Chromosome-Specific Introgression in Upland Cotton on Fiber and Agronomic Traits

“…While these species are hybridized easily, conventional backcrossing and/or inbreeding quickly lead to extensive germplasm loss (Stephens 1949). One of the challenges in interspecific introgression is to use valuable alien traits or genes of G. barbadense germplasm, such as fiber length, fineness, and strength for improvement of Upland cotton (Lacape et al 2005). Traditional plant breeding approaches to improve fiber quality through interspecific introgression have been hindered by complex antagonistic genetic relationships (Culp et al 1979).…”

“…The high value per hectare of cotton and global textile market demand for increased fiber uniformity, strength, extensibility, and quality clearly justify the importance of new and innovative approaches toward evaluating and understanding genetic mechanisms of fiber qualities. Recent molecular mapping studies associated G. barbadense chromosomes with many favorable QTL affecting fiber and agronomic traits (Rong et al 2004;Lacape et al 2005).…”