Genetic diversity of natural orchardgrass (Dactylis glomerataL.) populations in three regions in Europe

Abstract

BackgroundDactylis glomerata (orchardgrass or cocksfoot) is a forage crop of agronomic importance comprising high phenotypic plasticity and variability. Although the genus Dactylis has been studied quite well within the past century, little is known about the genetic diversity and population patterns of natural populations from geographically distinct grassland regions in Europe. The objectives of this study were to test the ploidy level of 59 natural and semi-natural populations of D. glomerata, to investigate genetic diversity, differentiation patterns within and among the three geographic regions, and to evaluate selected populations for their value as genetic resources.ResultsAmong 1861 plants from 20 Swiss, 20 Bulgarian and 19 Norwegian populations of D. glomerata, exclusively tetraploid individuals were identified based on 29 SSR markers. The average expected heterozygosity (HE,C) ranged from 0.44 to 0.59 and was highest in the Norwegian region. The total number of rare alleles was high, accounting for 59.9% of the amplified alleles. 80.82% of the investigated individuals could be assigned to their respective geographic region based on allele frequencies. Average genetic distances were low despite large geographic distances and ranged from D = 0.09 to 0.29 among populations.ConclusionsAll three case study regions revealed high genetic variability of tetraploid D. glomerata within selected populations and numerous rare and localized alleles which were geographically unique. The large, permanent grassland patches in Bulgaria provided a high genetic diversity, while fragmented, semi-natural grassland in the Norwegian region provided a high amount of rare, localized alleles, which have to be considered in conservation and breeding strategies. Therefore, the selected grassland populations investigated conserve a large pool of genetic resources and provide valuable sources for forage crop breeding programs.

Low Genetic Differentiation and Evidence of Gene Flow among Barley Landrace Populations in Tunisia

“…Among the major objectives of conservation programs is the maintenance of a maximal amount of genetic polymorphism (Luan et al, 2006). In this case, both in and ex situ measures should be taken into account (Last et al, 2013). In this case, both in and ex situ measures should be taken into account (Last et al, 2013).…”

Optimization of SCoT-PCR reaction system in Dactylis glomerata by orthogonal design

“…Molecular-level studies of orchardgrass have also been conducted. Numerous types of molecular genetic marker systems have been developed for use in germplasm resources studies of orchardgrass, including amplified fragment length polymorphism markers (Reeves et al, 1998;Peng et al, 2008), random amplified polymorphic DNA markers (Kölliker et al, 1999;Tuna et al, 2004), sequence-related amplified polymorphism markers (Zeng et al, 2008;Scoles et al, 2010), inter-simple sequence repeat markers (Zeng et al, 2006), simple sequence repeat (SSR) markers (Xie et al, , 2012Song et al, 2011;Last et al, 2013), and expressed sequence tag-SSR markers (Bushman et al, 2011). These studies have revealed varying levels of molecular genetic diversity depending on the type of molecular marker and the population examined (Mulpuri et al, 2013).…”

Genetic diversity and variation in North American orchardgrass (Dactylis glomerata L.) cultivars and breeding lines

“…; Last et al . , ); where each study found the majority of variation apportioned within cultivars or populations, and that entries did not always group as predicted by geographic provenance or ploidy level. However, the relationships among most North American cultivars and the levels of molecular variation within cultivars have not been characterized.…”

“…Several studies have examined orchardgrass populations with an objective to understand the genetic relationships among specific breeding materials. Molecular markers were used to compare orchardgrass populations or cultivars across Europe and Asia (Lumaret 1988;Koelliker et al 1999;Tuna et al 2004;Zeng et al 2008;Litrico et al 2009;Xie et al 2010;Bushman et al 2011;Last et al 2013Last et al , 2014; where each study found the majority of variation apportioned within cultivars or populations, and that entries did not always group as predicted by geographic provenance or ploidy level. However, the relationships among most North American cultivars and the levels of molecular variation within cultivars have not been characterized.…”