Exploring the genetic diversity in snapmelon (Cucumis melo var. momordica) landraces of Pakistan

Abstract

Among the major cucurbit vegetables, Cucumis melo has one of the highest polymorphic fruit types and botanical varieties. The present study was performed to evaluate the morphological and genetic diversity among different genotypes of Snapmelon (Cucumis melo var. momordica) taken from all the four provinces of Pakistan. For the morphological diversity various plant, leaf and fruit parameters were studied according to IPGRI-1998 plant descriptor. Data of these parameters was recorded in 40 genotypes of Snapmelon collected from different parts of the country. Young leaves of these genotypes were collected for DNA extraction through CTAB method, which was used for genetic analysis by SSR Markers. Principle component analysis was used to indicate the morphological diversity among 40 genotypes of Snapmelon collected from diverse origins of Pakistan. These showed the highest phenotypic diversity between the wild and the domesticated genotypes of Hyderabad and Nankana (tehsils), respectively. The morphological markers concluded the fact that the diversity exists in the landraces of Snapmelon in vegetative as well as in the reproductive characters. Moreover, the morphological markers revealed that most of the landraces of same geographical area clustered differently, which depicts the movement of the germplasm to other areas through various means. On the contrary, the results of the qualitative and quantitative analysis showed that the few Snapmelon landraces collected from diverse regions clustered together which indicate some type of commonality of origin among the germplasm of those landraces. The results of this research also support the view that morphological and chemical contents in fruits are reliable in estimating genetic relationships among the landraces of Snapmelon and can be used efficiently for discrimination. This study showed that Pakistani Snapmelon germplasm is a rich source of variation for traits of economic interests. This conclusion came from the high significant differences among the Snapmelon germplasm analyzed for quantitative variables combined with high standard deviation values and the presence of two or more phenotypic classes per trait. SSR markers were also tested on Snapmelon germplasm which yielded valuable information on the genetic relationships of these landraces. The genetic analysis through principle coordinate analysis and dendrogram showed that the 13 wild landraces were distinguished from all domesticated landraces collected from various regions of the country. In conclusion, the genetic diversity exists in various traits of Snapmelon landraces which can be further exploited to develop new combinations through conventional or biotechnological tools.