Ross Andrew Ballard

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Plant genotypes of Trifolium subterraneum L. (subterranean clover) were evaluated for differences in symbiotic N2 fixation with soil rhizobia, with the long-term aim of using plant selection to overcome sub-optimal N2 fixation associated with poorly effective soil rhizobia. Symbiotic performance (SP) was assessed for 49 genotypes of subterranean clover with(More)
The nucleotide sequence of the major outer membrane protein gene (omp1) was determined for three geographically distinct lymphogranuloma venereum isolates which were serologically untypeable. The three omp1 sequences were hybrids of serovars L1 and L2, containing a putative DNA recombination site in variable segment 2. Efforts to manipulate the chlamydial(More)
Endophytic actinobacteria are known to benefit their hosts by improving plant growth and by reducing the severity of soil borne diseases. In this study, their role in enhancing the growth of lucerne and their interaction with its rhizobial symbiosis is examined. Comparison is made between endophytic actinobacteria isolated from wheat plants and isolates(More)
The multiplication of root lesion nematode (Pratylenchus neglectus) was compared for 13 species of annual pasture legume (eight Medicago spp., two Lotus spp., two Trigonella spp. and Trifolium balansae), triticale (Secale cereale × wheat hybrid cv. Tahara) and wheat (Triticum aestivum cv. Machete) at two field sites in South Australia. At sowing, the(More)
In the past decades the increasing focus by Australian pasture development programs on the genus Lotus has seen the evaluation of many species previously untested in Australia. In field trials, nodulation failure was commonplace. This work was undertaken to select effective symbionts for Lotus to ensure further agronomic evaluation of the genus was not(More)
Hydrothermal vents jetting out water at 380 degrees +/- 30 degrees C have been discovered on the axis of the East Pacific Rise. The hottest waters issue from mineralized chimneys and are blackened by sulfide precipitates. These hydrothermal springs are the sites of actively forming massive sulfide mineral deposits. Cooler springs are clear to milky and(More)
The nematode Pratylenchus neglectus has a wide host range and is able to feed on the root systems of cereals, oilseeds, grain and pasture legumes. Under the Mediterranean low rainfall environments of Australia, annual Medicago pasture legumes are used in rotation with cereals to fix atmospheric nitrogen and improve soil parameters. Considerable efforts are(More)
Ensifer meliloti strain RRI128 is an aerobic, motile, Gram-negative, non-spore-forming rod. RRI128 was isolated from a nodule recovered from the roots of barrel medic (Medicago truncatula) grown in the greenhouse and inoculated with soil collected from Victoria, Australia. The strain is used in commercial inoculants in Australia. RRI128 nodulates and forms(More)
The effects of three endophytic Streptomyces on plant growth and the symbiosis of Lucerne and its rhizobial partner were examined in the presence of three levels of soil nitrogen. Three Streptomyces strains, LuP30 and LuP47B isolated from the roots of Lucerne (Medicago sativa L.) and EN23 isolated from roots of wheat (Triticum aestivum L.) were added as(More)
Significant simple correlations were found between productivity of radiata pine growing on known P-deficient soils and available soil P, mycorrhizae, slope, aspect, pH, and drainage. However, partial and multiple correlations showed that available soil P, mycorrhizae, fine sand, clay and slope were the only measured variables to make a significant(More)