Phenotypic or Molecular Diversity Screening for Conservation of Genetic Resources? An Example from a Genebank Collection of the Temperate Forage Grass Timothy

• Published in: Crop science 2015-07, Vol.55 (4), p.1646-1659
• Main Authors: Fjellheim, Siri, Tanhuanpää, Pirjo, Marum, Petter, Manninen, Outi, Rognli, Odd Arne
• Format: Article
• Language: English
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2014.12.0825

ABSTRACT Genebanks around the world represent a large source of genetic variation in both wild and crop species and may prove invaluable in the future. However, much of this is uncharacterized and this hampers both management and utilization, specifically of wild species and minor crops. In this paper we study a large genebank collection of wild populations of the cool‐season forage grass timothy (Phleum pratense L.) to investigate different methods for characterization and their implications for conservation. Populations covering the entire geographic distribution range of timothy were analyzed for simple‐sequence repeats (SSRs), chloroplast DNA (cpDNA) sequence, and phenotypic variation in 14 morphological and phenological characters. The east–west distribution of two major cpDNA haplotypes indicates a classic postglacial expansion pattern, with most populations originating from two refugia. No signs of geographic structuring of SSR variation were evident, indicating a large inherent effective population size, possibly in combination with extensive gene flow. In contrast to the lack of geographic structuring of variation in neutral markers, phenotypic variation was clearly structured, indicating natural selection and local adaptation. This study demonstrate the importance of using multiple characterization systems—both molecular and phenotypic—for assessing diversity in genebank collections, specifically when it comes to evaluating adaptive potential.