Genetic resources in Trifolium and their utilization in plant breeding

Abstract

Abberton, M. T., Thomas, I. (2011). Genetic resources in Trifolium and their utilization in plant breeding. Plant Genetic Resources: Characterization and Utilization, 9, (1), 38-44. RONO: 03131Clovers (Trifolium species) are a large and widespread genus of legumes. Recent work supports the Mediterranean origin of the genus in the Early Miocene period, and centres of diversity for clovers occur in the Eastern Mediterranean, East Africa and South America. A number of clovers are of agricultural importance as forage species in grassland agriculture around the world, particularly in temperate areas. White clover (Trifolium repens L.) is the most important legume of grazed pastures, and red clover (T. pratense) is widely cut and conserved as a winter feed. We consider the current state of collected resources in clovers, which have been collated in the most important databases. These are European Internet Search Catalogue (EURISCO), germplasm resources information network and system-wide information network for genetic resources together with the collection held at AgResearch, New Zealand. In total, collections have been made of 204 species with 48 species having more than 100 accessions in these databases. As expected, the majority of accessions are of the agriculturally important species. The geographical origin of collected material is outlined and, for the major species, accessions are broken down according to their status, e.g. wild population, breeders' lines. We then describe some of the ways in which genetic resources of white and red clovers and their relatives have been used in the breeding of these species. These include introgression of stress tolerance traits, targetting improvements in resource use efficiency and increasing seed yield.Peer reviewe

Legume Crops Phylogeny and Genetic Diversity for Science and Breeding

“…Overall, approximately 74,000 accessions of Trifolium are held in global ex situ collections, 53% of which are wild, 14% of which are cultivated and 33% are of unknown improvement status (FAO, 2010, Table 1 (2001) concluded that it contained gaps for (i) cultivars and landraces of red and white clover originating from China, Japan, South America, and South Africa; (ii) obsolete cultivars developed in the USA; (iii) minor-use species; (iv) related wild species; and (v) germplasm distinguished by traits that may be of value to the nutritional supplement or bioremediation industries and that may convey adaptation to abiotic stress or be supportive of sustainable agriculture. Other important questions that need to be examined in order to determine the global ex situ coverage of Trifolium include the extent to which current collections represent an appropriate level of geographical coverage around the globe and to what degree the major collections are sampling independent geographical regions (Abberton and Thomas, 2011). The study of variation in clover germplasm collections based on morphological, phenological, and agronomical characters and molecular markers has resulted in the development of core collections (Kouame and Quesenberry, 1993;Vymyslický et al, 2010Vymyslický et al, , 2012.…”

“…White clover develops a dense network of stolons, which enhances grazing tolerance, winter hardiness and persistence. Resistance to pests and diseases, efficient use of water and nutrients, and compatibility with grass are important targets of white clover breeding (Abberton and Thomas, 2011). Breeding programs for white clover are carried out throughout the world: New Zealand (Williams et al, 2007), Australia (Lane et al, 1997;Jahufer et al, 2002), the United States (Taylor, 2008) and the UK (Abberton and Marshall, 2010).…”

“…Breeding programs for white clover are carried out throughout the world: New Zealand (Williams et al, 2007), Australia (Lane et al, 1997;Jahufer et al, 2002), the United States (Taylor, 2008) and the UK (Abberton and Marshall, 2010). They are focused on particular environments and management systems but share the objectives of more fully realizing the potential of white clover to contribute to livestock nutrition and soil fertility (Abberton and Thomas, 2011).…”

“…Red clover is traditionally important in organic farming systems, where it is used as a source of nitrogen in crop rotation and for its high protein content in modern silage technologies. Red clover is an important feed resource for pollinating insects (Abberton and Thomas, 2011).…”

Breaking through the feed barrier: options for improving forage genetics

“…Both ryegrass and white clover have widespread genetic resources in situ, radiating from their Old World centres of diversity (Abberton and Thomas 2011). There are also extensive curated ex situ seed collections, including the Margot Forde Forage Germplasm Centre in New Zealand.…”