Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/22/2006
Publication Date: 6/1/2007
Citation: Kebede, H., Burow, G.B., Dani, R., Allen, R. 2007. A-genome cotton as source of genetic variability for upland cotton (gossypium hirsutum). Genetic Resources and Crop Evolution. 54(4): 885-895. Interpretive Summary: Upland cotton, one of the most economically important crops in the Southern US is generally considered to have narrow genetic base, which potentially limit its yield capability and make it vulnerable to adverse abiotic and biotic stresses. One possible solution to this dilemma is to utilize relatives of cotton including cultivated and exotic germplasm to serve as sources of desirable genes for abiotic and biotic stress tolerance in plant improvement programs. To be able to use the germplasm for research and actual breeding program, information on genetic variation available in the resource germplasm are needed. This study was conducted to asses the genetic variation in the 41 A- genome cotton and representative D- genome sources using microsattelites or simple sequence repeats. Genetically distinct groups of A-genome cotton were resolved using similarity and principal component analysis. The groups identified can be used for characterization of response to stress towards identification of important phenotype and QTLs related to stress tolerance.
Technical Abstract: Upland cotton (Gossypium hirsutum) is known to have narrow genetic base and low genetic diversity, which potentially limits its yield and predisposes the species to be vulnerable to adverse abiotic and biotic stresses. Therefore, analysis of genetic variation of the genus Gossypium, especially the diploids, which are the putative donors of the A and D genomes for the commercially important allotetraploid cottons (AADD) G. hirsutum and G. barbadense, is very important to obtain information on the feasibility of using these genetic resources for cotton improvement. The primary objective of this study was to analyze the genetic diversity in A-genome diploid cotton species, G. herbaceum (A1) and G. arboreum (A2) using microsatellite markers. A total of 41 A-genome germplasm accessions were evaluated using 32 microsatellite loci. Genetic similarities between A1 and A2 ranged from 0.62 to 0.86 with a mean of 0.70. Within each A-genome species similarities ranged from 0.80 to 0.97 with a mean of 0.89 for A1 and 0.82 to 0.98 with a mean of 0.89 for A2. UPGMA tree and principal coordinate analysis based on genetic similarity matrices showed distinct clusters consistent with the genomic groups. Genetically distinct accessions within the A genome cottons identified in this study could be utilized for characterization of important phenotype and QTLs associated with abiotic and biotic stress tolerance for eventual incorporation into the teraploid upland cotton genome.