Wageningen, The Netherlands
March 25, 2010

In March 2010 CGN has reduced the size of the lettuce collection with 197 accessions. This rationalization involved cultivated material that was represented more than once in the collection. By removing duplicates the same level of diversity can be maintained in a smaller number of accessions, thereby contributing to a more efficient conservation. The advantage for the user community is that less accessions need to be evaluated to find the traits of interest.

The rationalization study is described in Plant Genetic Resources: Characterization and Utilization.

Reference
Van Treuren R, IW Boukema, EC de Groot, CCM van de Wiel, ThJL van Hintum (2009) Marker-assisted reduction of redundancy in a genebank collection of cultivated lettuce. Plant Genetic Resources: Characterization and Utilization, DOI 10.1017/S1479262109990220.

Abstract

To reduce the level of redundancy in a collection of cultivated lettuce, data from 160 amplified fragment length polymorphism (AFLP) fragments and 10 polymorphic microsatellites were used in combination with passport data and morphological data, the latter obtained from an experimental field trial performed for verification purposes. Based on the observed distribution of the number of marker differences between and within accessions, a minimum of three AFLP differences and two microsatellite differences were regarded as levels warranting distinction between accessions in the redundancy analysis. The strategy followed in the redundancy analysis was mainly based on the confirmation of duplication by each of two independently generated data sources. The molecular data were used for the validation as well as the identification of potential duplicates, revealing a total number of 198 redundancies, corresponding to 12.9% of the total collection. Trueness to type, number of characterization and evaluation data, and collection management considerations, such as available seed quantities and germination percentages, were used as primary, secondary and tertiary criteria to decide which accession from duplication groups to maintain in the collection. Removal of accessions showed negligible effects on total collection diversity, as quantified for AFLPs and microsatellites, characterization and evaluation traits and resistance profiles against downy mildew pathotypes, indicating that the applied strategy was effective.

Source:
http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=6919788

Website: http://www.cgn.wur.nl/UK/

Published: April 15, 2010