Molecular dissection of interspecific variation between Gossypium hirsutum and G. barbadense (cotton) by a backcross-self approach: II. Fiber fineness.
A backcross-self population from a cross between Gossypium hirsutum and G. barbadense was used to dissect the molecular basis of genetic variation governing two parameters reflecting lint fiber fineness and to compare the precision of these two measurements. By applying a detailed restriction fragment length polymorphism (RFLP) map to 3,662 BC(3)F(2) plants from 24 independently derived BC(3) families, we were able to detect 32 and nine quantitative trait loci (QTLs) for fiber fineness and micronaire (MIC), respectively. The discovery of larger numbers of QTLs in this study than previously found in other studies based on F(2) populations grown in favorable environments reflects the ability of the backcross-self design to resolve smaller QTL effects. Although the two measurements differed dramatically in the number of QTLs detected, seven of the nine MIC QTLs were also associated with fiber fineness. This supports other data in suggesting that fiber fineness more accurately reflects the underlying physical properties of cotton fibers and, consequently, is a preferable trait for selection. "Negative transgression," with the majority of BC(3)F(2) families showing average phenotypes that were poorer than that of the inferior parent, suggests that many of the new gene combinations formed by interspecific hybridization are maladaptive and may contribute to the lack of progress in utilizing G. barbadense in conventional breeding programs to improve upland cotton.
Department of Soil and Crop Sciences, Texas A&M University, College Station, TX 77843, USA.
Xavier
X
Draye
Peng
P
Chee
Chun-Xiao
CX
Jiang
Laura
L
Decanini
Terrye A
TA
Delmonte
Robert
R
Bredhauer
C Wayne
CW
Smith
Andrew H
AH
Paterson
D000704:Analysis of Variance; D001947:Breeding / Q000379:methods*; D032561:Cotton Fiber; D003433:Crosses, Genetic; D014644:Genetic Variation; D003368:Gossypium / Q000235:genetics*; D010641:Phenotype; D012150:Polymorphism, Restriction Fragment Length; D040641:Quantitative Trait Loci; D012639:Seeds; D013045:Species Specificity