Features of subterranean clover
Subterranean clover is the most grazing tolerant pasture legume and has several features that make it well adapted to the farming systems of WA and southern Australia:
- It has an annual life cycle and grows from autumn to spring, which matches the time that most rainfall occurs.
- It regenerates naturally from seed set in previous seasons, without the need for re-sowing.
- It maintains a seed bank of ‘hard’ seeds, in which some seeds remain dormant for germination in later years, enabling regeneration after cropping or a year of little or no seed-set.
- It tolerates regular, close grazing (particularly set-stocking by sheep), due to its prostrate growth habit.
- It buries its burrs to protect seeds from being eaten by stock (particularly spp. subterraneum and yanninicum).
Origin of Australia’s subterranean clovers
Subterranean clover is not native to Australia, but occurs naturally in the Mediterranean basin and surrounding areas. It was accidentally introduced into Australia in the 19th century by the early settlers and was first commercialised in the early 1900s. Cultivars are derived from three main sources:
- accidental introduction from other countries, followed by colonisation and development of local types, known as ‘naturalised strains’
- deliberate collection of seeds from the Mediterranean region and surrounding areas
- breeding programs, involving crossing and selection of types with desirable traits.
To date 53 cultivars have been registered in Australia, although many are now out-dated. Most of the recent cultivars have been developed from breeding programs. The Department of Agriculture and Food, Western Australia (DAFWA) has released the most cultivars, with others released by the South Australian Research and Development Institute (SARDI) and by Italian researchers. Other varieties that have not been registered with the Australian Seeds Authority are also on the market.
Cultivar development has been aided by a large genetic resource of around 10 000 types that have been collected from its native habitat and naturalised strains from Australia. Identification of cultivars is based on variation in attributes (for example colour, hairiness) of the leaf, petiole, stipule, runner, flower and seed.
