Wednesday, November 15, 2006

Phylogeny and Determination of Possible Natural Hybridization among the Australian Arid Zone Gossypium Species.

Rashmi Tiwari and James Stewart. University of Arkansas, PTSC 115, Fayetteville, AR 72701

The Gossypium genus has about 45 diploid species with 26 chromosomes, grouped into eight genomic groups, A-G and K, and 5 allotetraploid species with 52 chromosomes. In Australian, there are 17 native Gossypium species and are all diploid. All of these species are grouped under the subgenus Sturtia, which is further divided into three sections, Grandicalyx (K genome, 12 species), Hibiscoidea (G genome, 3 species) and Sturtia (C genome, 2 species). The C and G genomes are sympatric in parts of their ranges. The main objective of this research is to identify the degree of genetic similarity/diversity and natural hybridization among Australian arid zone Gossypium species in the G genome. The proposed study will employ a DNA fingerprinting technique, Amplified Fragment Length Polymorphism (AFLP), to assess the genetic diversity among the Australian arid zone Gossypium species G. australe, G.bickii, and G. nelsonii. Accessions of G. sturtianum sympatric to these are analyzed for hybridization. The data will be analyzed by the computer software program Phylogenetic Analysis Using Parsimony (PAUP*).