Multivariate analysis of cucumber (Cucumis sativus L.) landraces in Central Nepal

Abstract

Cucumber is an important vegetable crop in Nepal. However, its improvement has been slow because the genetic diversity of cultivated varieties is limited and many local landraces have not been properly characterized. This study examined 24 cucumber landraces, along with Bhaktapur Local as a check, at the Nepal Agricultural Genetic Resource Centre to document their phenotypic variation and identify useful traits for breeding. The experiment was conducted in a Randomized Complete Block Design (RCBD) with two replications, and observations were recorded for 20 qualitative and 14 quantitative traits. Plant and leaf traits were generally uniform, while fruit colour, shape, and surface features showed considerable variation. Principal Component Analysis showed that the first three components explained 57 % of the total variation. PC1 mainly represented flowering and maturity traits, whereas PC2 and PC3 captured differences in vine length, leaf size, and node related traits. The PCA biplots clearly separated the landraces into groups based on their reproductive and vegetative characteristics, allowing the identification of types such as late flowering landraces (Co14943, Co13791) and early, compact ones (Bhaktapur Local A, Co13538). Cluster analysis grouped the landraces into four major clusters, with the greatest separation observed between Clusters I and III, suggesting useful parental combinations for breeding. Overall, the results indicate substantial phenotypic diversity among the Nepalese cucumber landraces and provide a strong basis for developing varieties with improved earliness, yield potential, and adaptability.