Using the Australian tropical forages collection to develop new pasture legumes for Australian rangelands

Abstract

Beef cattle production is the key agricultural industry in the seasonally-dry and moderate rainfall zones of northern Australia. Uncleared natural woodlands are the key feed resource in the northern monsoonal zone, whereas sown pastures dominate the moderate rainfall zone further south. In additional to seasonal feed gaps, beef producers face emerging challenges from declining land condition, a warming and more variable climate and pasture dieback associated with mealy bugs. Sown deep-rooted legumes (Desmanthus, Leucaena, Macroptilium, Stylosanthes) can improve productivity on these pastures by improving nitrogen cycling and improving diet quality. The development of tropical pasture cultivars in Australia is underpinned by the Australian Tropical Forages Collection (ATFC), now held in the Australian Pastures Genebank supported by state and federal governments and primary industry research and development corporations. The ATFC comprises ~10100 warm season grasses and 7300 legumes sourced from other tropical countries and within Australia over 40+ years, including over 4000 legumes from genera with potential in permanent or semi-permanent pastures in the dry zone. Comprehensive plant evaluation and release activities by federal and state governments saw the development of a network of on-property plant evaluation sites and the release of useful legume cultivars for key beef production land-types. However, some environments have no well-adapted pasture legumes. The evaluation site network has recently been exploited to develop legumes for frost-prone areas on light-textured soils and clay soils in the monsoonal zone. A Queensland government regeneration and characterisation program has also prioritised the development of legumes for the seasonally dry and moderate rainfall zones to enable access to seeds and plant traits to breeders both in Australia and overseas.