Submitted to: Agronomy Abstracts
Publication Type: Abstract only
Publication Acceptance Date: 5/25/2008
Publication Date: 10/5/2008
Citation: Saha, S., Raska, D.A., Jenkins, J.N., McCarty Jr., J.C., Wu, J., Stelly, D.M. 2008. Interspecific chromosome substitution lines in the genetic improvement of Upland cotton. Agronomy Abstracts. Paper No. 718-8. Interpretive Summary:
Technical Abstract: Competitiveness of US Upland (Gossypium hirsutum L.) cottons requires that new alleles useful for agronomic, fiber quality, and pest resistance must be introduced and bred into germplasm useful to plant breeders. Integrated use of marker-assisted selection will require that the existing and new alleles be identified or at least mapped. Thus, two key challenges in contemporary genetic improvement of cotton are 1) to better utilize germplasm resources, and 2) to gain useful information about genes that control important traits. The tetraploid species G. barbadense, G. tomentosum, and G. mustelinum are primary germplasm resources for new genes and prospective enhancements of pest and disease resistance, agronomic performance, yield and fiber traits. Conventional methods of interspecific introgression into cotton typically entail inbreeding immediately after hybridization or after a few backcrosses. A complementary if not superior breeding strategy may be to develop disomic chromosome substitution (CS) lines, whereby inadvertent germplasm loss is largely avoided, and the breeding products are well enough defined to use for breeding and genetic research. Development of each CS line requires  derivation of the recurrent parent, a monosomic or monotelodisomic hypoaneuploid Upland (‘TM-1’-like) plant,  hybridizing it to a donor species and backcrossing to create a mono(telodi)somic substitution stock,  inbreeding to recover a euploid disomic substitution line, and  confirmation of the cytogenetic and genetic constitution of the disomic lines by cytological analysis and chromosome-specific molecular markers. We have developed 20 backcrossed (BC5) G. barbadense chromosome or chromosome arm substitution lines (CS-B) of Upland cotton. These CS-B lines provided important information about the effects of specific G. barbadense substituted chromosome on important fiber and agronomic traits. An additive dominance genetic model has demonstrated that they can be used effectively to improve Upland cultivars. Moreover, we are using the CS-B lines for detection of inter-chromosomal epistasis and high-resolution definition and mapping of QTLs. CS lines for G. tomentosum and G. mustelinum, CS-T and CS- M lines, are now also in development, and should contribute significantly to interspecific introgression for genetic analysis and Upland cotton improvement.