Trifolium interspecific hybridisation: widening the white clover gene pool
W. M. Williams
+ Author Affiliations
- Author Affiliations
AgResearch Grasslands Research Centre, Private Bag 11008, Palmerston North 4442, New Zealand; and College of Sciences, Massey University, Palmerston North 4442, New Zealand. Email: warren.williams@agresearch.co.nz
Crop and Pasture Science 65(11) 1091-1106 https://doi.org/10.1071/CP13294
Submitted: 28 August 2013 Accepted: 2 November 2013 Published: 14 April 2014
Abstract
White clover (Trifolium repens) is adapted to moist, fertile soils in temperate zones. Despite its heterozygous allotetraploid nature, it lacks useful genetic variation for survival and growth in semi-arid, infertile soils. Although white clover is apparently genetically isolated in nature, 11 other taxa have so far been found that can be artificially hybridised into the wider gene pool. These species range from annuals to long-lived, hardy perennials with adaptations to stress environments, and they potentially provide new traits for the breeding of more resilient varieties of white clover. The delineation of the secondary, tertiary and quaternary gene pools is described, along with a review of interspecific hybrids achieved to date. The results of large breeding programs to integrate traits from T. nigrescens and 4x T. ambiguum are reviewed, and schemes introduced for the use of T. uniflorum, T. occidentale, T. pallescens, 2x T. ambiguum and 6x T. ambiguum. Interspecific hybrid breeding of white clover has the potential to enable the development of resilient perennial clovers for seasonally dry, infertile grassland environments in many parts of the world.
Additional keywords: Trifolium ambiguum, Trifolium nigrescens, Trifolium occidentale, Trifolium uniflorum, Trifolium pallescens.
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