CGN lamb’s lettuce collection
Lamb’s lettuce (or corn salad) is a relatively small crop assigned to the group of minor leafy vegetables. As CGN’s collection of lamb’s lettuce has a very short history, the collection has not yet been extensively described by characterization and evaluation data, nor has it so far been widely utilized for breeding and research. More information about several aspects of the collection can be accessed below.
History
CGN’s collection of lamb’s lettuce has a relatively short history. In 2008 it was agreed to include a selection of the most important Dutch varieties in the collection of the German national genebank in Gatersleben. In 2010 CGN’s new policy to specialize in vegetable crops resulted in the start of the development of several new crop collections.
These new collections also included lamb’s lettuce due to its relatively poor representation of genetic resources in existing collections and the importance of the crop to the Netherlands. As it was decided that CGN’s lamb’s lettuce collection should also contain the important national varieties, some degree of overlap with the German collection was unavoidable. Currently (April 2020), the collection consists of nearly 50 accessions, making it one of the largest lamb’s lettuce collections in the world.
Maintenance
Germination thresholds for uptake of lamb’s lettuce in the collection are similar to those used for other CGN crops, i.e. 80% for cultivated material and 60% for accessions of wild species.Lamb’s lettuce accessions are regenerated under controlled greenhouse conditions.
To regenerate accessions, seeds are sown in November and plants are overwintered under frost proof greenhouse conditions. Due to the selfing nature of lamb’s lettuce, regeneration can be carried out without specific protective measures to avoid pollination between accessions. A few meters distance is maintained between accessions to minimise the risk of contamination. Seed harvesting takes place in May-June. More detailed information about regeneration procedures can be accessed through the link provided in the right margin of this page.
Composition
Collection development started in 2011 with the acquisition of the main Dutch varieties of cultivated lamb’s lettuce (Valerianella locusta). Subsequently, the collection was extended with cultivars and landraces originating from other European countries, in particular Germany and France, as far as the material was not yet properly conserved and distributed by other national genebanks.
In 2013 a start was made with the sampling of natural populations of V. locusta in the Netherlands, followed by the collecting of specimens of related species occurring in the Netherlands, including V. carinata, V. dentata and V. rimosa. Currently (April 2020), 46 accessions are available for distribution, including seven represented by wild species. The collection may be extended with wild specimens in the future through collecting outside the Netherlands.
Characterisation & Evaluation
Phenotypic data for cultivars that were described by the Netherlands Inspection Service for Horticulture (Naktuinbouw) are made available as downloadable files on CGN’s website. In 2019 the entire collection was grown in a field trial and described for various morphological traits. Also these data and pictures of the materials are available from CGN’s website. Evaluation programs with the breeding industry have so far not taken place.