Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2003
Publication Date: 12/1/2004
Citation: Kato, C.Y., Nagai, C., Moore, P.H., Zee, F.T., Kim, M.S., Steiger, D.L., Ming, R. 2004. Intra-specific dna polymorphism in pineapple (ananas comosus (l.) merr.) assessed by aflp markers. Genetic Resources and Crop Evolution. 51:815-825. Interpretive Summary: Mother Nature, though evolution, and mankind, through intentional breeding and selection, have produced a diverse range of life forms, each with its particular characteristics and attributes. Since these life forms may be valuable today or in the future, it is society's desire to preserve as many of these forms as economically feasible. The problems are that preservation is so expensive that we can afford to save only the most different forms and we do not have a quantitative measure of the level of diversity, especially among understudied tropical plant species. We report the development of methodology and applying it to an evaluation of the genetic diversity of a collection of pineapple varieties and related plants. Although previous research had reported very little differences among cultivars of pineapple our DNA analyses showed a high degree of variation. We used this data to develop a molecular "fingerprint" of the various accessions. This data can be used then to authenticate the identity of specific lines and to design cost-effective strategies for the preservation of the maximum amount of diversity at the least cost.
Technical Abstract: Pineapple (Ananas comosus L.) cultivars, often derived from somatic mutations, are propagated vegetatively. It has been suggested by isozyme data that there is little genetic variation among Smooth Cayenne cultivars. A thorough investigation of the genetic variation within the cultivated species Ananas comosus, particularly among commercial cultivars, will provide critical information needed for crop improvement and cultivar protection. One hundred forty-eight accessions of A. comosus and 14 accessions of related species were evaluated with AFLP markers. The average genetic similarity of A. comosus was 0.735 ranging from 0.549 to 0.972, suggesting a high degree of genetic variation within this species. With AFLP markers, discrete DNA fingerprints were detected for each commercial cultivar, breeding line, and intra-specific hybrid. Self-incompatibility, high levels of somatic mutation, and intra-specific hybridization may account for this high degree of variation. However, major cultivar groups of pineapple, such as Cayenne, Spanish, and Queen, could not be distinctively separated. These cultivar groups are based on morphological similarity, and the similar appearance can be caused by a few mutations that occurred on different genetic background. Our results suggest that there is abundant genetic variation within existing pineapple germplasm for selection, and discrete DNA fingerprinting patterns for commercial cultivars can be detected for cultivar protection. The genetic diversity and relationships of four Ananas species are also discussed.