Analysis of genetic variation in Cucurbita moschata by random amplified polymorphic DNA (RAPD) markers

Knowledge of genetic relationships among genotypes is essential for the eff ective utilisation of germplasm, especially for poorly characterised specie s. Random amplified polymorphic DNA (RAPD) analysis provides a quick and re liable method for resolving genetic relationships. Although Cucurbita mosch ata Duch, also known as tropical pumpkin, is one of the most important vege table crops in Africa, being adapted to a wide range of climatic and soil c onditions, it is a scientifically neglected species. The objectives of this study were to (1) analyse the amount of genetic diversity in C. moschata l andraces grown in south-central Africa and (2) classify the landraces to as sist in selection of parent genotypes for improvement of fruit characterist ics. Cluster analysis, based on 39 polymorphic and 105 monomorphic DNA frag ments amplified by 16 primers, was used to show relationships among 31 geno types obtained from Zambia and Malawi. The analysis revealed four clusters, with genotypes from Malawi mainly clustering in three clusters while all g enotypes from Zambia and three from Malawi clustered in one cluster. The pa ir-wise mean genetic distance was 0.32 +/- 0.04 for samples from Malawi and 0.26 +/- 0.04 for samples from Zambia. The possible application of the res ulting classification in breeding of C. moschata is discussed.