Genetic Diversity of Chinese Key Cottons with Fusarium and Verticillium Wilts Resistance Based upon AFLPs

Genetic diversity of 105 Chinese key cottons with Fusarium and Verticillium wilts resistance was studied based on AFLP markers. Twenty primer combinations were selected to perform the AFLP fingerprinting from 100 primer combinations. A total of 1498 DNA fragments were scored among all materials, averaging 74.9 for each primer combination, of which, 232 ((15.5%)) bands were polymorphic. The number of DNA bands per primer combination ranged from 49 to 111, with the average of 11.6 polymorphic markers. Forty-six cultivars, as much as 43.81% of the 105 materials, had specific bands. The primer combination, E41/M50, made 10 materials produce specific markers. Mean pairwise genetic distance of 105 cultivars (lines) was 4.353,with the range of 1.732 to (6.708.) Range of mean genetic distance for each variety was 3.531~5.705. Less than 50% of materials were below mean genetic distance. The limited genetic diversity was revealed by these results in the population. Based on dendrogram of AFLPs, 105 cultivars (lines) were classified into five upland cotton groups (UCGs). The number of cottons was different in each UCGs, and their geographic origins and descents were diverse.