Association mapping for cassava mosaic disease (cmd) resistance in cassava using SSR marker

Abstract

The present study” Association mapping for Cassava Mosaic Disease (CMD) resistance in cassava using SSR marker” Was conducted to identify the marker which are closely associated with CMD resistance in cassava. 30 CMD resistant and 25 CMD susceptible cassava varieties were analyzed with 2n selected SSR primers. Genomic DNA isolated from the leaves and PCR amplification was done with SSR primers. PCR products were separated by PAGE. Polymorphic bands were used to assign loci for each primer and score as presence (1) or absence (0) of bands. RMEI primer showed double banding pattern in 700bp size for all the resistant accessions. But in case of susceptible accessions only single bands were observed. TASSEL and STRUCTURE software were used ro analyses the data obtained from the PAGE.. Cladogram was constructed using genotypic data. Different clusters were formed. Clusters clearly distinguished CMD resistant and CMD susceptible varieties of cassava. CMD resistant varieties sub divided into three sub clusters. Dissimilarity matrix constructed by the software used for the diversity study of collected cassava accessions. Two markers were associated with CMD resistance was identified by the software. SSR36 are the two markers associated with CMD resistance. Result showed that there are eight sub populations in the cassava population used. Based upon the output obtained from Evanno’s method a bar diagram was constructed. Which shows the distribution of genotypes in different sub populations.