Submitted to: Molecular Breeding
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/4/2009
Publication Date: 3/1/2009
Citation: Gutierrez, O.A., Stelly, D.M., Saha, S., Jenkins, J.N., McCarty Jr., J.C., Raska, D.A., Scheffler, B.E. 2009. Integrative placement and orientation of non-redundant SSR loci in cotton linkage groups by deficiency analysis. Molecular Breeding. 23:693-707. Interpretive Summary: Hawaiian cottons have several characteristics such as tolerance to high temperature, resistance to insects and good fiber properties that could help to improve cultivated Upland cotton. Combining the best agronomic qualities of the Upland cotton plant with the best properties of Hawaiian cotton plant has been difficult for cotton breeders due to incompatibility between the two plants. An alternative approach to incorporate Hawaiian cotton characteristics into an Upland background would be to utilize chromosome substitution lines. The methodology allows the segmented incorporation of Hawaiian cotton traits into cultivated cotton. Molecular markers such as Simple Sequence Repeats (SSR) have been used as a tool in crop improvement by plant breeders. The purpose of this research was to identify chromosome substitution lines of Hawaiian cotton using Simple Sequence Repeat (SSR) markers. Plants containing several Hawaiian cotton chromosomes were developed for assignment of SSR markers and were fingerprinted using SSR primer pairs that were previously assigned to these specific chromosomes. Results indicated that SSR markers were able to identify many of the chromosome substitution lines based on deletion analysis.
Technical Abstract: A set of new chromosome substitution lines has been initiated using G. tomentosum Nuttall ex Seemann (2n=52) as the donor and Upland cotton (Gossypium hirsutum L., 2n=52) as the recurrent parent. The interspecific hypoaneuploid F1 substitutions are hemizygous for a specific chromosome or segment, and thus useful for identifying chromosomal locations of DNA markers and linkage groups. The objectives of this study were: 1) to confirm the hypoaneuploid status of the chromosome substitution lines based on cytological analysis of G. tomentosum using Simple Sequence Repeat (SSR) markers and 2) to evaluate the use of these chromosome substitution lines as an alternative resource for the assignment of SSR markers to chromosomes. As reported elsewhere, monosomes for G. tomentosum chromosomes 1, 2, 4, 6, 7, 9, 10, 12, 16, 17, 18, 20, and 25 as well as monotelodisomes for chromosome arms Te01sh, Te01Lo, Te02sh, Te02Lo, Te03sh, Te03Lo, Te04sh, Te04Lo, Te05Lo, Te06sh, Te06Lo, Te07sh, Te08Lo, Te09Lo, Te10Lo, Te10sh, Te11Lo, Te12Lo, Te14Lo, Te15Lo, Te16Lo, Te17sh, Te18Lo, Te18sh, Te20Lo, Te20sh, Te22Lo, Te22sh, Te25Lo, and Te26sh were used for the assignment of the SSR markers. The cytogenetic stocks were fingerprinted using SSR primer pairs that were previously assigned to these chromosomes using aneuploid chromosome substitution (CS-B) lines of G. barbadense. In addition, the genetic standards TM-1 (G. hirsutum), 3-79 (G. barbadense L.) and the aneuploid F1 substitution lines for the chromosome and chromosome arm of G. barbadense were also used as references to confirm the results. Results based on deletion analysis indicated that SSR markers enabled identification of interspecific aneuploid lines for all the chromosomes with the exception of Te15Lo. In addition, one new SSR locus was assigned to chromosome-8.