Molecular and farmer-based comparison of a wild-weed and landrace complex of watermelon in Zimbabwe

Traditional farming systems have been associated with the occurrence of intervarietal and interspecific natural crosses in many crop plants, thus contributing to the genetic diversity of the crop through genetic exchange. In this study, a combination of farmerpreferred morphological traits and RAPD markers were used to evaluate the dynamics of genetic diversity in 43 watermelon accessions collected at a single village level with a traditional farming system. The molecular variability assessed with RAPD markers and analyzed with multidimensional scaling and cluster analysis, demonstrated a substantial differentiation among the accessions. Population structure analysis also demonstrated the existence of three major forms of watermelon, identified by a set of alleles predominant within each form. Dendrograms based on RAPD data and on farmer-preferred traits data were positively correlated according to a Mantel test. Although cultivated cow-melons were genetically most similar to wild-weedy plants at molecular level, they grouped more similar to sweet watermelons based on farmer-preferred traits. The present study revealed limited gene flow between three forms of watermelon and provides insight into how the genetic differentiation corresponds to farmers’ classification of watermelon

Uganda: gold as a (trans)national treasure

NWOGlobal Challenges (FSW

Application of EST-SSR marker in detection of genetic variation among purslane (Portulaca oleracea L.) accessions

Express sequence tag (EST)-simple sequence repeat (SSR) was employed to assess the genetic diversity in elite germplasm collections of purslane (Portulaca oleracea L.) which is a saline and drought tolerant annual herb containing high amount of vitamins, minerals, and antioxidant properties. The 10 primers gave a total of ninety-five bands among which 95 were polymorphic (100 %). The genetic diversity as estimated by Shannon’s information index was 1.85, revealing a high level of genetic diversity in the germplasm. The average numbers of observed allele, effective allele, expected heterozygosity, polymorphic information content (PIC), and Nei’s information index were 9.5, 5.14, 0.81, 0.33, 0.77, and 0.79, respectively. The UPGMA dendrogram based on Nei’s genetic distance grouped the whole germplasm into eight distinct clusters. The analysis of molecular variance (AMOVA) revealed that 71.87 % of total variation occurred within population while 28.13 % from among populations. Considering all these criteria and results from marker-assisted diversity analysis, accessions that are far apart based on their genetic coefficient (like Ac11 and Ac17; Ac4 and Ac42; Ac16 and Ac31; Ac38 and Ac17; Ac21 and Ac31; Ac30 and Ac10) could be selected as parents for further breeding programs