No description available.

Bibliography: leaves 102-107 / 107 leaves : ill ; 31 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agronomy, Waite Agricultural Research Institute, 1984

xi, 157 leaves : ill., graphs, tables ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Entomology, 1980

The worldwide utilisation of Vicia species as forage and green manure crops is well established. Except for V. faba L., the utilisation of Vicia species as grain legumes is of minor global economic importance and mainly restricted to the Mediterranean region and South - West Asia, where the grain is used primarily as seed and in ruminant diets. In Australia, the comparatively high seed yields and low production costs for genotypes from species such as V. narbonensis L. (narbon bean or moor's pea) and V. sativa L. (common vetch) have provided an attractive alternative grain legume option for dryland farming and have thus stimulated an interest in markets for the grain. Monogastric animals (incl. humans) are the major global end-users for grain legume products. Because of the well known toxicity of Vicia spp. seeds to mono gastric animals in particular, this thesis has focused on those major toxic chemical seed components which are perceived as major constraints to the wider utilisation of these promising crops as grain legumes. A thorough examination of current and past practices of vetch cultivation and utilisation was undertaken to complement this approach. The two major aims were, first to elucidate the nature of the factors responsible for the low palatability of carbon beans to pigs, and second to review the available information about the toxicity of Vicia species and their utilisation as grain legumes. The potent feed inhibitory activity of Namoi vetch (V. villosa Roth cv. Namoi) provided a useful model for the initial age of this study. Its antifeedant activity was shown to he due to the toxic amino acid canavanine. Inclusion of canavanine in pig diets at a concentration equivalent to that found in Namoi vetch seed accounted fully for the feed inhibitory activity of this legume. The novel effect of this well known arginine analogue may well be explicable in terms of the inhibition of the argmine pathway leading to nitric oxide which is now known to be involved in the control of peristalsis. The experience gained with Namoi vetch in the feed-intake bioassay proved to be invaluable for the isolation of the much less potent y- glutamyl-S-ethenyl-cysteine feed inhibitor from the narbon bean. A quantitative assessment of this factor's feed inhibitory activity was not permitted due to the untimely death of our veterinary colleague, Dr. Richard Davies. There is, however, a clear correlation between the total S-ethenyl cysteine content of the tested diets and the negative porcine feed intake responses. An important difference between V. villosa and V. narbonensis was noted, as demonstrated by the rate at which the pigs reduced their feed intake. It is remarkable, that the effect of canavanine - containing diets becomes evident only after the second meal, whereas the pigs immediately restrict their feed intake when presented with diets containing S-ethenyl-cysteine. Such a clear delineation of feed-intake responses provides a simple and general classification for feed-intake inhibitors, and may be worthy of further detailed physiological studies. The antifeedant effects of these compounds suggest that they have evolved as part of the plants' anti-predator defence strategy. Particular attention, including a detailed review of its economic botany, has been given to V. narbonensis, a relatively unknown but promising grain crop for Australia. With the chemical identity of the unpalatability established, the selection of more palatable genotypes is likely to provide access for the grain to monogastric feed markets. The historical evidence suggests that V. narbonensis is a niche crop of particular value for specific agricultural applications, its conversion into a broad acre crop is a challenge for the future. V. sativa was investigated as a direct consequence of a request to chemically examine the toxin content of the cultivar Blanche Fleur. By the time that investigation commenced, Blanche Fleur, which was originally introduced to Australia as a hay, forage and green manure crop, had already been prematurely promoted and exported as a cheap replacement for red lentils (Lens culinaris Med.) in ignorance of this species' well documented content of y- glutamyl-β-cyanoalanine and the favism toxin, vicine. A 1992 commentary article to Nature on our observations led to a ban on its importation by India and Egypt. Subsequent poultry bioassays established that the cyano- alanine content was substantially altered by cooking to produce some as yet un-identified nitrile component, but the feed inhibitory activity of the cooked grain was undiminished. Acid hydrolysis of Blanche Fleur, however, removed both, the readily detectable nitrile absorbance as well as the poultry feed-intake inhibition. This observation could potentially form the basis for a simple post-harvest detoxification process for V. sativa and other feed stuffs containing acid labile antinutritive factors. Unfortunately, cases of poisoning by Vicia species continue to be reported. These can be grouped into those caused by V. sativa and its related species (cyanogenic glycoside Vicianine: HCN poisoning; and anti- nutritional effects of (β- cyanoalanine )and those caused by canavanine containing species ( V. villosa, V. benghalensis, V. ervilia etc.). Farmers need to be made aware of the well documented biochemical distinctions between Vicia cultivars to prevent the accidental intoxication of their livestock with seeds containing high concentrations of canavanine orvicianine. Finally, an overview of the voluminous and widely dispersed vetch literature, coupled with the observations in this thesis, suggest that the utility and value of each of the three Vicia model species examined in this thesis can be markedly enhanced by the following strategies : 1. Provision of sufficient alternative feed sources to allow feed intake to be regulated by palatability, thus rninirnising toxin ingestion. 2. Adaptation to Vicia toxins a) through selection of a digestive flora capable of detoxification (in the case of ruminants) and b) through selection or modification of animal genotypes with improved biochemical tolerance or even resistance to toxicity. 3. Detoxification prior to ingestion (Post - harvest detoxification) 4. Plant selection or genetic modification of specific toxin biosynthetic pathways to provide cultivars with optimum toxin concentration and distribution in strategic tissues (minimisation of toxins in the end product). The inevitable conclusion from this thesis is that by incrementing our current fundamental knowledge of the biological chemistry of their naturally occurring anti-predator metabolites, we will promote the intelligent usage of Vicia species as highly nutritious grains for a sustainable agriculture. This thesis has resulted in 2 publications in referred journals. / Thesis (Ph.D.)--Department of Plant Science, 1994.

[Truncated abstract] Faba bean (Vicia Faba L.) ranks third worldwide in overall production among coolseason legume crops and is used as a main source of protein both for food and feed purposes in many parts of the world. Australia is a major exporter of faba beans and the price received depends on the quality of the seed especially colour of the seed coat. Consumers don?t like faba beans that are dark coloured or that have blemishes on the seed coat. Environmental staining and storage discolouration deteriorate seed colour causing substantial economic losses to growers and grain handlers. To investigate the influence of environmental conditions, especially during pod/seed development and maturity, on the degree of environmental staining, field trials were conducted using four faba bean varieties (Fiord, Fiesta, Ascot and Cairo) in a range of environmental conditions under the Mediterranean-type climate of south western Australian grain belt. Although a majority of seeds had good colour but 3-25% were stained up to an unacceptable level across the trials and this varied with location and variety. Seeds formed later in plant development (located on the upper nodes of the plant) were more stained than seeds formed earlier (located on the lower nodes). This may be due to end of season environmental factors, such as high temperature and light intensity, and water and nutrient stress. Similarly seeds formed on small and weak plants, which may have developed under stressful conditions, had more staining than seeds formed on normal sized and healthy plants. Genotypic variation was also evident with Fiord showing greater staining than Ascot, Fiesta and Cairo. The cause of environmental staining appears to be complex but was associated with phenolic contents. Storage discolouration was influenced by a number of factors including temperature, seed moisture content, light and storage period and these were critical in determining storage life. ... Faba bean hardness, examined by the hard-to-cook test, also increased with increased storage temperature. There was a high negative correlation (r2 = 0.98) between storage temperature and cooking ability of faba bean. There was a three-fold increase in lignin content of faba bean stored at 50°C compared to those stored at 5°C and it was correlated with bean hardness (r2 = 0.98). Reduction in free phenolics was negatively correlated (r2 = 0.75) with bean hardness. The environmental staining in faba bean can be minimized with correct choice of varieties, robust agronomic practices to establish and maintain healthy plants and the use of mechanical graders and colour sorters. For minimizing storage discolouration faba beans must be dehydrated to ≤12% seed moisture content and stored in insulated bins (silos) or at least bins painted white and constructed under trees shades. In addition occasional flushing with N2 will further help reduce the colour darkening. The above approaches will improve quality, market opportunities, price and hence profitability of faba bean in the farming systems.

Thesis (Ph. D.)--University of Adelaide, Dept. of Plant Science, 1996. / Includes bibliographical references (leaves 209-254).

Thesis (Ph.D.)--Murdoch University, 2008. / Thesis submitted to the Faculty of Sustainability, Environmental and Life Sciences. Includes bibliographical references (leaves 111-135).

Thesis (M.Sc.)--Memorial University of Newfoundland, 2004. / Bibliography: leaves 117-146.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1964. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 85-91).

Thesis (Ph.D.) - University of Queensland, 2006. / Includes bibliography.