Genetic variability in wild vs. cultivated Eruca vesicaria populations as assessed by morphological, agronomical and molecular analyses

In this study, the genetic diversity of 50 individuals of rocket, Eruca vesicaria, from five accessions, four of them wild type collected from different parts of Spain and one commercial, were evaluated using morphological, agronomical and inter simple sequence repeat DNA (ISSR) data. Molecular analysis was carried out using the ISSR technique with 20 primers. Out of these 20 primers, nine were polymorphic, producing a total of 395 DNA bands, 247 of which were polymorphic among the accessions. A dendrogram drawn on the basis of a similarity matrix using the UPGMA algorithm revealed that the 50 samples of rocket plants could be classified into three major clusters at a Nei's genetic distance of 0.36. The experiment shows that molecular markers such as ISSR are a good instrument for distinguishing and selecting rocket accessions to group different wild populations. In general, a high variation was observed for most of the 16 morphological and 6 agronomical traits showing significant differences. Some morphological traits such as leaf length, petiole length and lamina width explained 69.1% of the whole variation observed in the populations, and some agronomical traits such as leaf area, nitrate and chlorophyll contents accounted for 65.7%, but the clusters generated by means of agronomical and morphological variables were less evident than when ISSR markers used. Some accessions showed good qualities, such as small leaves, high chlorophyll content, late-flowering or low nitrate content. All these parameters, together with the high degree of genetic homogeneity found, could make the local accessions good candidates for a future breeding programme.