AFLP And SSR Genetic Polymorphism Study Among Cassava Varieties

Cassava is as important dry land crop and the one of three big yams crop in the world. Guangxi is the biggest producer area of cassava in China, and there are rich cassava genetic resources presently. Morphological markers is an usual method to analysis genetic polymorphism in cassava, but the method is limited by many conditions such as the seasons and the environment. The molecular marking is the new method of data emerging from DNA-based techniques. It is not limited by seasons and environment, and is able to expressing genetic information accurately.Twenty-one cassavas varieties in this experiment come from main cultivated variety and importance breeding resource. This DNA genetic diversity was analyzed by using SSRs and AFLPs in this experiment, and 22 SSR primer pairs and 3 pairs of AFLP selective amplified primers utilized. Using the data obtained, the similarity coefficient was calculated and UPGMA clustering analyzed on computer among these cassavas varieties. Results of the two kinds of molecular markers showed as follows:(1) The genome DNA of cassava was obtained with the improved method of CTAB, their concentration and purity is enough for PCR amplification and digest.(2) The genetic similarity coefficient was high among all varieties in the result of two molecular marks, with genetic similarity from 0.435 to 0.813 in SSR and from 0.625 to 0.865 in AFLP.(3) Only a part of different existed between two molecular markers clustering results, Also has a part of difference with the available pedigree.(4) The cassava DNA also was amplified with the litchi, the melon and peanut's SSR primers in the experiment, and the results confirmed that the transferability of SSR primers was not incapable.The results provided the theory basis for the cassava molecular-breeding in selecting parents.