|Campbell, Benjamin - Todd|
Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 9/20/2010
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Three of the research areas likely to very significantly impact genetic improvement of cotton are interspecific introgression, genetic dissection of complex traits and sequencing of [AD] genomes. Interspecific introgression is expected to increase genetic diversity of breeding germplasm, creating opportunities for novel and faster rates of genetic improvement. Genetic dissection of complex traits is expected to render the improvement process more amenable to various types of marker-assisted selection. Sequencing and assembly of the [AD]1 genome and other Gossypium genomes will usher forth a new paradigm for research and breeding. Here we will describe collaborative interspecific chromosomes substitution program, in which we are developing quasi-isogenic substitution lines of Upland cotton (recurrent parent) for specific chromosomes of G. barbadense, G. tomentosum and G. mustelinum (donors). After briefly reviewing the breeding process to create cotton chromosome substitutions and the complementarity of this breeding method to other means of interspecific introgression, we will discuss the longer-term goals, including genomic analysis, genetic dissection and genetic improvements. A number of the interspecific F1 hybrid hypoaneuploids have been used to localize a number of markers to specific chromosomes or arms. The most advanced CS line efforts involve G. barbadense as donor, and have already led to the development and release of a number of BC5Sn “CS-B” lines. These and various types of derived hybrid progenies from them have been used in replicated testing to associate specific stocks with important effects on fiber and agronomic traits. We have used the existing CS-B lines to create quasi-isogenic F1, F2 and F3 generations and to begin dissecting genetic effects quantitatively in a chromosome-targeted manner. We created topcrosses with five cultivars, and demonstrated their usefulness for discovery of breeding-relevant cultivar-to-cultivar variations. Using a partial diallel mating scheme, we have begun to dissect the “holy grail” of interspecific introgression, epistasis. We have also initiated chromosome-specific dissection of quantitative trait loci (QTLs), by initiating the development of chromosome-specific recombinant inbred lines (CS-RILs) for higher resolution mapping. The anticipated completion of chromosome substitution line development for G. tomentosum (“CS-T lines”) and G. mustelinum (“CS-M lines”) will further expand the breeding and research opportunities in terms of breeding genetics and genomics. All of these materials will provide additional tools in genomic analysis and genetic improvement of Upland cotton, and help expedite the organization of genomic resources into chromosome-specific bins; creating smaller target areas will facilitate sequence assembly and organization of certain genome assembly tasks. An important subsequent application of these advances is likely to be the implementation of trait-targeted genome selection to wide-cross introgression populations using high-throughput genome-wide genotyping methods.