Domestication of New Mediterranean Annual Pasture Legumes

Abstract

Fifteen years ago subterranean clover (Trifolium subterraneum L.) and annual medics (Medicago spp.) dominated annual pasture legume sowings in the Mediterranean-like climate of southern Australia. Since then a number of sustainability and economic challenges to existing farming systems have emerged, exposing shortcomings in these species and a lack of legume biodiversity. A selection program, largely based in Western Australia, with testing sites across southern Australia, has responded to these challenges by domesticating new annual pasture legume species native to the Mediterranean basin to overcome the deficiencies in traditional species (Nichols et al., 2007). Seven new species to agriculture have been commercialised (Ornithopus sativus, Biserrula pelecinus, Trifolium glanduliferum, T. dasyurum, T. spumosum, T. purpureum and Medicago sphaerocarpos), while Lotus ornithopodioides and Melilotus siculus are under evaluation. Traits incorporated include deeper root systems, protection from false breaks (germination-inducing rainfall events followed by death from drought), a range of hardseed levels, acid-soil tolerant root nodule symbioses, tolerance to pests, diseases and salinity and provision of less expensive seed through ease of seed harvesting and processing. The contributions of genetic resources, rhizobiology, pasture ecology and agronomy, plant pathology, physiology, entomology, plant chemistry and animal science have been paramount to this success.