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United States Department of Agriculture

Agricultural Research Service

Research Project: Germplasm Enhancement and Genetic Improvement of Cotton Title: Delineation of Interspecific Epistasis on Fiber Quality Traits in Gossypium hirsutum by ADAA Analysis of Intermated G. barbadense Chromosome Substitution Lines

Authors
item Saha, Sukumar
item Wu, Jixiang -
item Jenkins, Johnie
item McCarty, Jack
item Hayes, Russell
item Stelly, David -

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 13, 2011
Publication Date: March 1, 2011
Citation: Saha, S., Wu, J., Jenkins, J.N., McCarty, J.C., Hayes, R.W., Stelly, D.M. 2011. Delineation of interspecific epistasis on fiber quality traits in Gossypium hirsutum by ADAA analysis of intermated G. barbadense chromosome substitution lines. Theoretical and Applied Genetics. 122:1351-1361.

Interpretive Summary: Non-domesticated tetraploid cotton genotypes are useful sources for the exploration for genes of potential value for the improvement of Upland cotton. Cotton breeders have long been aspired to develop Upland cotton with elite fiber qualities of Pima cotton (G. barbadense). However, the incompatibility between these two species was a major constrain with the conventional methods of interspecific introgression. An alternative approach to interspecific introgression is the use of alien chromosome substitution lines where individual chromosomes or chromosome arms of G. barbadense have been substituted into G. hirsutum (CS-B lines). Using a partial diallel crossing scheme among the selected chromosome substitution lines (CS-B lines) we provided a method for chromosome specific introgression of beneficial alleles of fiber quality traits from Pima cotton to Upland cotton. This report also revealed detailed and precise QTL dissection as well as the allelic interaction effects between two alien substituted chromosomes versus one alien substituted chromosome on fiber quality traits. Data were analyzed according to the ADAA genetic model, which revealed significant additive, dominance, and additive by additive epistasis effects on all of the fiber quality traits associated with the substituted chromosome or chromosome arm of CS-B lines. Multiple antagonistic genetic effects were associated with most of the substituted chromosomes and chromosome arms. Results from this study revealed the importance of epistasis in fiber quality traits and detected novel effects of some cryptic beneficial alleles affecting fiber quality on the 3-79 chromosomes, whose effects were not detected in the 3-79 parental lines.

Technical Abstract: Genetic diversity is the foundation of any crop improvement program, but the cultivated Upland cotton (Gossypium hirsutum L.) has a very narrow gene pool resulting from its origin and domestication history. G. hirsutum L., the most extensively cultivated cotton species, is characterized by agronomic traits including high yield, with good fiber properties, whereas, G. barbadense L. has exceptionally good fiber qualities, but agronomic traits are not as favorable as Upland. Breeders have long aspired to combine the best attributes of G. hirsutum and G. barbadense, but have had limited success because of the biological and technical challenges associated with the conventional methods of interspecific introgression. Using a partial diallel crossing scheme among selected chromosome substitution lines (CS-B lines) we provide a much more detailed and precise QTL dissection as well as the allelic interaction effects between two alien substituted chromosomes versus one alien substituted chromosome on fiber quality traits in this report. Data were analyzed according to the ADAA genetic model, which revealed significant additive, dominance, and additive by additive epistasis effects on all of the fiber quality traits associated with the substituted chromosome or chromosome arm of CS-B lines. Fiber of line 3-79, the donor parent for the substituted chromosomes, had the highest Upper half mean length (UHM), uniformity ratio, strength, elongation, and lowest micronaire among all parents and hybrids. CS-B16 and CS-B25 had significant additive effects for all fiber traits. Assuming a uniform genetic background of the CS-B lines, the comparative analysis of the double-heterozygous hybrid combinations (CS-B x CS-B ) versus their respective single heterozygous (CS-B x TM-1) demonstrated that interspecific epistatic effects between the genes in the chromosomes played a major role in most of the fiber quality traits. Results showed that fiber of several hybrids including CS-B16 x CS-B22Lo, CS-B16 x CS-B25 and CS-B16 x TM-1 had significantly greater dominance effects for elongation and hybrid CS-B16 x CS-B17 had higher fiber strength than their parental lines suggesting interaction effects among the heterozygous loci on the substituted chromosomes caused the increase in the genetic effects. Multiple antagonistic genetic effects were also present for fiber quality traits associated with most of the substituted chromosomes and chromosome arms. Results from this study highlight the vital importance of epistasis in fiber quality traits and detected novel effects of some cryptic beneficial alleles affecting fiber quality on the 3-79 chromosomes, whose effects were not detected in the 3-79 parental lines.

Last Modified: 12/22/2014
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