Genetic Diversity of Introduced Accessions of Four Species of Banksia (Proteaceae) as Revealed by RAPDs and TBP Markers

Abstract

A population of several Banksia species, mainly B. ashbyi, B. integrifolia, B. praemorsa and B. prionotes propagated by seed was characterized at the Estacion Experimental Agraria de Elche (IVIA), Spain. Considerable levels of morphological variability were observed, especially in relation to their adaptation to the local alkaline soils. Since selection and breeding is difficult due to the long growing cycle of this perennial shrub, it would be desirable to use molecular markers in order to estimate genetic diversity. Thirty well adapted 12-year-old individuals were selected namely, ten individuals of B. integrifolia, ten of B. prionotes, five of B. ashbyi and five of B. praemorsa respectively. In addition, eight young plants that originated from seed of a single 12-year-old B. integrifolia plant were also analyzed to evaluate the genetic diversity within the offspring of a single plant. The well known RAPD technique and another marker technique based on tubulin polymorphism (TBP) were used. Genetic diversity was detected in the individuals analyzed, even though these individuals had been previously selected for their adaptive ability to local conditions. Interestingly, edaphic conditions of the experimental site where the plants have been cultivated for 12 years were considered not very suitable for Banksia species. However, apparently enough variability seemed to be present to guarantee that genetic selection is possible.