Genetic divergence analysis in eggplant (Solanum melongena L.) and allied species

Genetic divergence in 98 accessions of Solanum melongena L. and its allied species S. aethiopicum L. and S. macrocarpon L. for 16 morpho-agronomic and fruit traits revealed the existence of considerable diversity. Such collections were grown in the field during the 5 year EU-EGGNET project for characterization and seed multiplication. Diversity has been observed between the different species as well as within the species. Frequency distributions for fruit pedicel length, bitter flavour, browning, peelability, and cooking test were determined. Besides the qualitative descriptors, 11 quantitative descriptors were described. The relationships among them were analysed by Principal Component Analysis in order to summarize the data and reduce the number of variables for clustering. Plant height, flowering time, flower/inflorescence, fruit length and fruit acidity contributed mostly towards total divergence. Cluster analysis conducted separately for each species, in relation to the genetic status of accession (sub-species, botanical or variety group, cultivar and population), grouped the accessions into three distinct and significant clusters. No relationship was found between genetic divergence and genetic status of sample. In addition, relevant fruit discrete descriptors were used as a classification variable to ascertain whether some of them correspond to certain morpho-agronomic properties. The genotypes included in the diverse clusters could be used as promising parents for hybridisation in order to obtain a high heterotic response and thus contribute to eggplant breeding.