Juan B. Martínez-Laborde

Seed image analysis and taxonomy of Diplotaxis DC. (Brassicaceae, Brassiceae)

The genus Diplotaxis, comprising 32 or 34 species, plus several additional infraspecific taxa, displays a considerable degree of heterogeneity in the morphology, molecular markers, chromosome numbers and geographical amplitude of the species. The taxonomic relationships within the genus Diplotaxis were investigated by phenetic characterisation of germplasm belonging to 27 taxa of the genus, because there is an increasing interest in Diplotaxis, since some of its species (D. tenuifolia, D. muralis) are gathered or cultivated for human consumption, whereas others are frequent arable weeds (D. erucoides) in many European vineyards. Using a computer-aided vision system, 33 morpho-colorimetric features of seeds were electronically measured. The data were used to implement a statistical classifier, which is able to discriminate the taxa within the genus Diplotaxis, in order to compare the resulting species grouping with the current infrageneric systematics of this genus. Despite the high heterogeneity of the samples, due to the great intra-population variability, the stepwise Linear Discriminant Analysis method, applied to distinguish the groups, was able to reach over 80% correct identification. The results obtained allowed us to confirm the current taxonomic position of most taxa and suggested the taxonomic position of others for reconsideration.

Time of seed collection and germination in rocket, Erucavesicaria (L.) Cav. (Brassicaceae)

The increasing importance of rocket Erucaspp. as a leaf and oil crop, and especially as a Fourth Generationvegetable, calls for a better understanding of several basic aspectsof its biology. Knowledge on seed germination behaviour is necessaryto optimize the management of the plant in the field and inseedbanks. Seed germination of several samples of rocket was assayedin the laboratory under different incubation conditions. Germinationin the two studied populations was fairly high, ranging from68% to 96%. However, remarkable variation was foundwithin one of them according to the date of collection of the sample,ranging from 78–96% for those collected in summer(LG1 and LG2) to 21–29% for that collected inautumn (LG3). Neither time of storage nor GA3treatments had any significant effect on this low percentage, whichcould only be significantly improved with scarification, up to47% by dry heat and up to 66% by immersion in liquidnitrogen. Dormancy and low seed viability probably originating fromeffects of environmental factors during seed formation and maturationseem to play a role in the low germination percentage of sampleLG3.

An exploration of wild Brassica oleracea L. germplasm in Northern Spain

An intense exploration of the Spanish Cantabrian coast for the presence or absence of wild Brassica oleracea L., yielded 24 new localities to be added to the 21 previously known. Of the resulting 45 localities, 22 correspond to Asturias, 11 to Cantabria and 12 to the Basque Country. Data on the habitat requirements of this plant have been annotated, the conservation status of each population has been estimated and seed samples have been collected for long-term preservation. As a whole, wild B. oleracea is not threatened in Northern Spain, but some populations and/or sub-populations are at risk either because of their small size or some detectable human impact.

Germinability of Vicia sativa L. seeds After 10 Years of Storage in a Base Collection

The germinability of the Vicia sativa L. seed samples in the base collection at the Centro de Recursos Fitogenéticos (Spain) was controlled in 1986 and 1996. The mean germination of the collection, assessed by One-Sample T Test, was higher than 85%, suggesting its viability was properly maintained along the period. However, changes in germination along the same period assessed by Paired-Samples T Test showed a slight decrease in its global germinability. More data on the viability of stored seeds worldwide – including communication of unpublished data – are needed. Viability assays should be performed according to standard, internationally coordinated protocols and statistical analysis, within an adequate documentation system that assures the integrity of accession information.