The sheep grazing tolerance of a diverse range of lucerne germplasm (Medicago sativa subspp. sativa, falcata and caerulea) was investigated at Roseworthy in South Australia. Lucerne entries were established on a sandy loam soil in 1998 and managed with rotational grazing management for the first 12 months. Continuous grazing by sheep in the following year reduced the plant density of each entry as measured by plant frequency estimates by 2–98%. Lucerne was allowed to recover, then grazed continuously for another 12 months. There was great diversity in tolerance to sheep grazing among the entries tested, with final plant frequency ranging from 0–13% for highly winter-active entries, 7–23% (at least 7–23 plants/m2) for winter-active entries and 11–40% for winter dormant entries. A grazing tolerance index of commercial cultivars was determined by comparing their plant frequency decline under continuous grazing to that under rotational grazing in an adjacent experiment. Australian-bred highly winter-active cultivars displayed a greater level of tolerance than those developed overseas. The superior performance of several breeders’ lines in the continuously grazed trial indicates there is further scope for improvement with selection and breeding.
A total of 62 perennial grasses were evaluated for herbage production under low-fertiliser conditions at eight sites in the temperate zone of southern Australia from 1999 to 2001. A brief assessment of relative preference ranking by sheep was also made at the end of the experimental period. Four sites were in the high rainfall areas of south-east Australia, two in the drier mixed farming areas of western NSW, and two sites in Mediterranean southern Australia. Seven standard cultivars were included in the comparisons. Plants were grown from seed in glasshouses and transplanted to the field as spaced plants at 6–8 weeks age. Plants were harvested at irregular intervals by clipping to determine herbage production. Relative preference was determined by enclosing sheep in the experimental area at high stocking rates and estimating the amount of herbage grazed after 1, 3 and 5 days. Herbage production data were analysed using a multi-environment trial approach in which the environments comprised all combinations of sites and sampling times over the 3-year period. Overall, 73.6% of the total genetic variation for herbage production was accounted for. Average seasonal comparisons revealed good herbage production from Eragrostis curvula cv. Consol in both winter and summer, but in spring, several Dactylis glomerata lines were the most productive. Consol was not generally preferred by sheep, while D. glomerata lines were. Apart from cv. Consol, C4 species, including Bothriochloa macra, Chloris truncata, Enteropogon acicularis and Dichanthium sericeum had low herbage production in winter and spring, and had low acceptability to grazing sheep. These particular grasses were also not highly ranked for production in summer, although other C4 lines, notably selections of Themeda australis, Paspalidium jubiflorum and P. constrictum were. Few native C3 grasses had superior herbage production, although selections of Elymus scaber, Austrodanthonia fulva and A. duttoniana showed good growth rates. When considering further evaluation, grasses with very high recruitment (e.g. A. caespitosa) may need to be included, and the acceptability of grasses to sheep should also be assessed.
This paper is the fifth in a series describing trials evaluating native and introduced grasses at eight locations across temperate Australia. In these trials, 62 perennial grass lines were assessed for herbage production, survival and recruitment under low fertiliser conditions using spaced plants produced in glass houses and transplanted into the field. Sites were grouped into three different climatic zones: Eastern Australian permanent pasture, Eastern Australian mixed farming and Mediterranean zone. For each of these zones, superior lines were identified and their potential use in permanent pastures or mixed farming discussed. Among the C3 grasses tested, several lines of Dactylis glomerata from France on the Mediterranean coast near the Spanish border and from north-west maritime France proved to be superior lines in all zones and were better than the standard comparator cv. Currie with regard to the attributes assessed. In general, the D. glomerata lines were superior to the C3 native species except with respect to survival and recruitment. The C4 introduced standard comparator Eragrostis curvula cv. Consol was outstanding with regard to its herbage production and survival in all climatic zones, although its recruitment was generally low. Native C4 lines of Themeda australis and Paspalidium jubiflorum yielded well in all climatic zones, and even produced more herbage than Consol in one zone. Survival rates of T. australis and P. jubiflorum were also very high but recruitment was low under the conditions of the trial. In mixed pastures C4 grasses may reduce fluctuations in feed supply as well as increase water use. As a consequence mixtures of superior C3 and C4 lines identified in this study are likely to be suitable for pastures on infertile soils and in zones subjected to continuous or periodic drought. Further work on the behaviour of these superior lines under sward conditions in association with forage legumes and their responses to grazing is needed; however, for the promising native lines, sward trials are not possible until suitable technology for commercial seed production and broad acre establishment of these lines has been developed.
Abstract. The seed and forage production of a diverse group of the perennial forage legume Cullen spp., collected in southern Australia, was assessed with the aim of discovering diversity for exploitation in future breeding programs. Eighty ecotypes were assessed at the Waite Institute in South Australia, using replicated, spaced-plant field trials, between 2008 and 2012. Seed production in collected ecotypes of Cullen (Expt 1) ranged from 0 to 485 kg ha -1 for windrowed seed yield and from 0 to 790 kg ha -1 for total seed yield, which included vacuum-harvested seed from pods that had fallen to the ground. Individual plants were selected for seed production from their original populations, and the seed and fodder production of their progeny was evaluated in a further field experiment (Expt 2). Moderate to high heritability estimates were recorded for seed production traits. Seed production in progeny families ranged from 0 to1 423 kg ha -1 and was highly correlated with the number of seeds per inflorescence (r = 0.85) and forage yield (r = 0.59). Edible biomass, measured using the Adelaide visual appraisal method, ranged from 50 to 906 g dry weight (DW) plant -1 in parent ecotypes and from 404 to 1248 g DW plant -1 in the selected family progenies. Disease infection with anthracnose (Colletotrichum trifolii) caused considerable damage to plants in Expt 1, resulting in the death of all plants of 10 ecotypes, and infection with Alfalfa mosaic virus in Expt 2 was linked to the death of 67 individuals. The results are discussed in relation to breeding C. australasicum for increased seed yield and disease resistance to overcome these deficiencies as barriers to commercial adoption.
This paper describes the experimental methodology, sites, seasonal conditions and germplasm used in the Australian Native and Low Input Grass Network (NLIGN). In 1998, eight sites were established across the temperate pastoral zone of southern Australia. These were located at Armidale, Binya, Sutton and Trangie in NSW; Springhurst in Victoria; Jericho in Tasmania; Flaxley in South Australie and Kendenup in Western Australia. A total of 62 lines were evaluated, of which, 29 were Australian native grasses and 33 were introduced. With differences in seed size among species and a lack of information on dormancy and germination characteristics of the native plants, seedlings were transplanted into the field on weed-mat as spaced plants. Lines were compared over a 3-year period from 1998 to 2001. Methods used for determination of forage production, persistence and palatability are described. Information detailing the original collection sites of the germplasm, a list of NLIGN sites where each genotype was evaluated, as well as a detailed description of sites and seasonal conditions is also presented.
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