Evaluation of genetic diversity in cucumber (Cucumis sativus L.) germplasm using agro-economic traits and microsatellite markers

- Genetic diversity of 38 cucumber accessions from 9 countries was evaluated.
- Yield, yield component and microsatellite marker data were used to estimate diversity.
- Phenotypic data showed extremely broad range indicating high level of genetic variation.
- SSR markers have higher discriminative power than phenotypic data to separate cucumber accessions.
- Clustering methods separated the accessions to 3 groups reflecting the geographical origins.

Cucumber (Cucumis sativus L.) is one of the most economically important plants in many countries of the world. Thirty-eight cucumber accessions were evaluated for their genetic diversity using eight agro-economic traits (yield, fruit weight, flesh pith width, flesh pith length, fruit length, harvesting period, number of fruits per plant, and fruit color) and 20 microsatellite markers. Phenotypic data were collected in field for nine crop cycles. The correlation analysis of phenotypic data revealed that yield significantly correlated with fruit weight, flesh pith length, fruit length, harvesting period, and number of fruits per plant. Genotypic data from SSR markers identified 36 polymorphic loci. The polymorphism information content (PIC) averaged at 0.33 and ranged from 0 to 0.62. Genetic diversity and principal component analysis showed three main clusters corresponding to cucumber country of origin. Interestingly, these clusters can also be grouped by several phenotypic traits including yield and number of fruits per plant. The data obtained from this study can be used to select the best parental lines for plant breeding program and for genetic improvement in cucumber.