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

Knowledge of genetic relationships among genotypes is essential for the effective utilisation of germplasm, especially for poorly characterised species. Random amplified polymorphic DNA (RAPD) analysis provides a quick and reliable method for resolving genetic relationships. Although Cucurbita moschata Duch, also known as tropical pumpkin, is one of the most important vegetable crops in Africa, being adapted to a wide range of climatic and soil conditions, it is a scientifically neglected species. The objectives of this study were to (1) analyse the amount of genetic diversity in C. moschata landraces grown in south-central Africa and (2) classify the landraces to assist in selection of parent genotypes for improvement of fruit characteristics. Cluster analysis, based on 39 polymorphic and 105 monomorphic DNA fragments amplified by 16 primers, was used to show relationships among 31 genotypes obtained from Zambia and Malawi. The analysis revealed four clusters, with genotypes from Malawi mainly clustering in three clusters while all genotypes from Zambia and three from Malawi clustered in one cluster. The pair-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 resulting classification in breeding of C. moschata is discussed.