Genomic assessment of white clover and perennial ryegrass genetic resources

Abstract

Forage resources conserved in genebanks, such as the Margot Forde Germplasm Centre (MFGC; PalmerstonNorth), are reservoirs of genetic diversity important for the development of cultivars adapted to abiotic stresses and environmental constraints. Genomic tools, including genotyping-by-sequencing (GBS), can support identification of manageable subsets (core collections) that are genetically representative of these large germplasm collections, for phenotypic characterisation. We used GBS to generate SNP (single nucleotide polymorphism) profiles for 172 white clover (WC) and 357 perennial ryegrass (PRG) MFGC-sourced accessions and estimated genetic relationships amongst accessions. In WC, accessions aligned along an east-west transect from Kazakhstan to Spain, identifying major diversity in Caucasus/Central Asia and Iberian Peninsula. A key feature was the reduced diversity present in New Zealand (NZL) accessions. Similarly, for PRG, most NZL accessions coalesced as one group, distinct from large clusters associated with the Iberian Peninsula, Italy and eastern Mediterranean/Caucasian region. These results emphasise the relatively narrow genetic diversity in NZL WC and PRG, and the broad extent of largely unexploited global diversity. Capturing global genetic variation incore collections will support pre-breeding programmes to mobilise novel genetic variation into New Zealand-adapted genetic backgrounds, enabling development of cultivars with non-traditional traits including enhancedclimate resilience and environmental performance.

Unexpected Intraspecific Variability of Perennial Ryegrass (Lolium perenne L.) in Response to Constant Temperature During Germination and Initial Heterotrophic Growth

“…Knowing the intraspecific phenotypic and genotypic variability is essential for any selection and breeding program. Despite the high genetic diversity of this species in the wild, the genetic basis of modern cultivars is extremely narrow (Blanco-Pastor et al, 2019;Faville et al, 2020).…”

Identification and Characterization of Perennial Ryegrass (Lolium perenne) Vernalization Genes

“…Given the differences in LpVRN1 response seen in ONE50 plants above, we next aimed to determine whether the expression levels of LpVRN1 , LpVRN2a , LpVRN2b and LpCO9 might contribute to the differences in vernalization response in different ryegrass genotypes ( Table 1 ). Ryegrass genotypes were selected from a range of geographic locations, as well as a number of commercially grown cultivars with different flowering habits, in an effort to capture a wide array of genetic variation ( Table 1 ; Faville et al, 2020 ). In wheat and barley, vernalization induces changes in gene expression of VRN1 , firstly transiently, and then through stable epigenetic marks ( Yan et al, 2003 ; Oliver et al, 2009 ; Diallo et al, 2012 ).…”

The contribution of perennial ryegrass (Lolium perenne L.) breeding to whole pasture productivity under dairy cattle grazing in New Zealand. 1. Variation in yield, nutritive value and persistence‐related traits

“…Perennial ryegrass breeding in New Zealand since c. 1995 has drawn heavily on later‐flowering diploid material facilitated by use of germplasm from climate analogue regions in Europe notably NW Spain (Stewart, 2006; Faville et al, 2020; Table 1). Tetraploidy has been another key breeding tool, although in the early 2010s, only 5–6 tetraploid perennial cultivar‐endophyte combinations were marketed.…”

“…Other accessions that have not come through in commercial material to‐date (e.g. Faville et al, 2020) may contain useful traits, but these will still need to be balanced against other, non‐negotiable traits such as herbage yield, seed yield and disease resistance (Stewart & Hayes, 2011). Other temperate species such as cocksfoot (e.g.…”