Home / Journals / American Journal of Life Sciences / Genetic Variation in Naturalized Wild Radish (Raphanus Raphanistrum) Populations in South-Western Australia: a Comparison of Life History Traits and Aflp Molecular Markers
Genetic Variation in Naturalized Wild Radish (Raphanus Raphanistrum) Populations in South-Western Australia: a Comparison of Life History Traits and Aflp Molecular Markers
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University of Western Australia,
Four populations of wild radish (Raphanus raphanistrum) were sampled from south- Western Australia. Genetic variation within and between populations was measured and compared between amplified fragment length polymorphism (AFLP) and plant life history traits. It was hypothesised that populations from nearby sites would show greater similarity than more widely separated sites, and that populations from environmentally similar sites would show greater similarity than populations from dissimilar sites and that this would be most marked in life history traits. The primer combination EcoRl AAC/MseI CAA resulted in a total of 448 loci, of which 99% of the Merredin, 84% of the Nukarni, 93% of the Mullewa and 88% of the Denmark loci were polymorphic. Principal coordinates analysis and cluster analysis showed that variation within populations (71.7%, Fst= 0.71) was higher than variation between populations (28.3%, Fst=0.28). The Nukarni population appeared to be the most distinctive. The Mullewa and Merredin populations showed the greatest level of similarity. The Denmark and Mullewa populations were most distinct in terms of life history traits. The Denmark population had the largest pods and seeds, while the Mullewa population had the smallest. The results from the life history study support the hypothesis that environment is strongly influencing these traits, especially the seed and pod size. The genetic markers however, despite separating the biotypes, did not support the hypothesis that the greatest differences would arise from populations separated most in terms of space and environment. Indeed, the results suggest that wild radish was introduced to Western Australia on several occasions, with the likelihood that the Merredin and Nukarni populations represent separate introductions. Nevertheless, the life history traits reveal that evolution since introduction is convergent while environmental conditions are similar and divergent where they differ.