Ground Cover Supplement : GC Supplement - Pastures
GROUND COVER PASTURES 20 SULLA (HEDYSARUM CORONARIUM) is a her- baceous, winter-growing, short-term perennial forage legume with exceptionally high production potential that is suited to alkaline clay to loamy soils, particularly calcareous soils in the southern Queensland grainbelt. Sulla originates from the Mediterranean region of southern Europe and northern Africa, where it is agricul- turally significant as a hay and fodder plant. It is also used commercially in New Zealand. Individual plants live for two to three years and regenerate readily from seed. The herbage of Sulla is at least as nutritious as lucerne. It also has the capacity to produce large quanti- ties of fodder in winter and spring, particularly in the second year of production. It has reputed worm-control properties (based on overseas research) and is non- bloating, due to the presence of condensed tannins in the foliage. Sulla has been evaluated in Queensland since the 1960s, but its potential in the subtropics has only been recognised since the 1998 National Annual Pasture Legume Improvement Program (NAPLIP) nursery stud- ies with more recently collected germplasm. This has resulted in the evaluation of new accessions and the selection of elite lines from which to breed Australian cultivars, through collaborative research between the Queensland Department of Primary Industries and Fisheries (QDPI&F), the South Australian Research and Development Institute (SARDI) and the NSW Department of Primary Industries (DPI). Two synthetic lines have been selected for release – WilpenaA (a tall-growing type) and MoonbiA (a pros- trate type) – and commercial seed is expected to be available in 2007. WilpenaA was bred from two acces- sions, one from Bulgaria with high seed and vegetative yield and one from Morocco with high seed yield. MoonbiA was bred from four lines, two from Italy, one from Sicily and one from Tunisia. Two of the parents were selected for high dry-matter production, three for seed yield and two for hardseed level. In Queensland, a semi-commercial demonstration of sulla was sown at ‘Trimac’ Poll Dorset stud, Aubigny, on the eastern Darling Downs, where studmaster Chris Rubie was impressed with its potential. Sulla is able to fill the autumn to early summer feedgap in his enterprise, one that is traditionally difficult to fill. Before the commercial seed of the new Australian cultivars was available, an area of 1.6 hectares was sown to the New Zealand cultivar Aokau in May 2005. Mr Rubie says growing sulla in a season of limited rainfall convinced him it is a serious replacement for the only alternative winter forage, oats. Sulla’s drought resistance due to a deep taproot, pattern of production and lower production costs compared with oats (no need for nitrogen fertiliser) make it ideal. The stand produced five tonnes of dry material per hectare (DM/ha) by mid-September when it was grazed for 21 days with 40 rams of 90 kilograms live weight (LW) and 10 ram lambs of 40kg LW. During spelling between early October and early November, the stand regrew and produced 4t DM/ha. From mid-November it was grazed by 50 ram lambs of 60kg LW for 20 days, fol- lowed by 38 ewe lambs of 50kg LW for 30 days. Thus, in its establishment year, sulla sustained 3190 grazing days with sheep and lambs of a range of live weights. During both grazings, the sheep were introduced before the sulla plants grew tall and stemmy. Anecdotally, it appears that ‘early’ grazing rather than crash-grazing ensures effective regrowth of this legume. Sulla is extremely palatable. Among 35 species of 12 genera of temperate pasture legumes sown in an adja- cent trial, it was the first legume to be selected by Poll Dorset sheep and the most heavily grazed. In evaluation trials in Queensland, the Australian sulla cultivars – particularly WilpenaA – have produced more forage and seed than Aokau, and it is expected they will also be even more productive and resilient than Aokau. However, two root-rotting diseases, one caused by Rhizoctonia solani AG 2-2 and the other by Sclerotium rolfsii, can cause severe plant loss in sulla stands on bri- galow and black-earth soils respectively in Queensland. Breeding for resistance to both organisms is difficult but a screening technique for Rhizoctonia root rot has developed. A breeding program to improve the resis- tance has produced F1 progenies that are being screened before further crossing. David Lloyd is principal agronomist (pastures) with the Queensland Department of Primary Industries and Fisheries. GRDC Research Codes DAS324, CSA3 More information: David Lloyd, 07 4688 1261, firstname.lastname@example.org Sulla -- a new short-term perennial legume PROJECTS: NATIONAL ANNUAL PASTURE LEGUME IMPROVEMENT PROGRAM -- SOUTH AUSTRALIAN AND QUEENSLAND COMPONENTS (AWI & GRDC). DAVID LLOYD PERENNIALS Sulla, well grazed by Poll Dorset ram lambs at 'Trimac', Aubigny, Queensland.
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