[A and D genome evolution in Gossypium revealed using SSR molecular markers]

Genetic diversity analysis of diploid and allotetraploid cotton species was carried out using SSR molecular markers by selecting representative species having A and (or) D genome in Gossypium. Ten diploid cotton species in A and D genomes had high polymorphism and the molecular cluster was consistent with Gossypium classification previously reported by Fryxell. From molecular level, G. gossypioides belonging to D genome had low similarity matrix compared with other diploid D genome species. Diploid cotton species separately having A or D genome had their high similarity matrix. The research supported that G. gossypioides was the most original cotton species among all D genome species, different genomes in Gossypium had common origin and made evolution separately. To better understand genetic events that accompany allopolyploid formation, we add 2 cultivated allotetraploid cotton species in our research materials. However, the results showed that it was not appropriate to study evolution of A and D genome in Gossypium using cultivated allotetraploid cotton species. In order to solve the question, original arboreum, herbaceum and wild types of allotetraploid cotton species should be adopted. Further evolution research on cotton species based on the transcription level of cotton genome is being carried on.