Thesis (Ph.D.) Dept. of Plant Physiology, University of Adelaide, 1982. / Typescript (photocopy).

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

Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Soil and Land Systems, 2004. / "November 2004" Includes bibliographical references (leaves 182-189). Also available online.

Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Soil and Land Systems, 2004? / Includes bibliographical references. Also available in print form.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1955. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 258-265).

No description available.

Biofertilisers are rhizosphere microorganisms inoculated to reduce the need for N or P fertiliser application and maximise plant growth and nutrition, resulting in greater grain yield and N or P content. This study aimed to evaluate the effectiveness of diazotrophic bacteria isolated from the rhizosphere of wheat in Victoria, Australia. This thesis shows that N2-fixing Burkholderia species have great potential as biofertilisers on wheat productivity. In Chapter 2, strains of bacteria were isolated from wheat-growing soils in main Victoria wheat belt at Horsham and Birchip in North West Victoria. Strains were identified as Burkholderia spp. by their closest matches in the 16S DNA and by morphology and physiology. In Chapter 3, one selected strain from each of Birchip and Horsham were used to inoculate wheat in a pot trial in a glasshouse during winter-spring. Soil was collected on site from wheat fields. Pots were inoculated with these strains to evaluate the effects of Burkholderia inoculum as biofertiliser on the plant growth and yield. Different nitrogen sources (urea 46% N and ammonium sulphate 21% N) were used as fertiliser at one of four levels (0, 50, 100 and 150 kg N/ ha). There was a greater effect in Birchip than in Horsham soil and with ammonium sulphate than with urea due to waterlogying in Horsham soil. In Chapter 4, field-grown wheat was inoculated with the same strains of Burkholderia. Three experiments were carried out in plots at two sites, dryland and irrigated fields at Horsham and a dryland field at Birchip, during the winter wheat season of 2006, to evaluate the effect of Burkholderia species inoculum and different types of nitrogen source at one of four levels of added N (0, 50, 100 and 150 kg N/ha) on wheat growth and yield. The effects of both bacterial inoculation and N fertiliser on growth promotion and grain yield. Since 2006 was a year of drought, dry land crops were unsuccessful. Grain %N as well as total N content in grain per area in the Horsham irrigated field increased with increasing N fertiliser levels up to 100 kg N/ha. In Chapter 5, acetylene reduction (ARA) activity was measured in the pots for both inoculated and uninoculated plants at various growth stages and populations of nitrogen-fixing bacteria associated with the wheat roots and bulk soil were measured in addition to biomass and N content of plants and grain. Molecular tracing using specific primers showed that the inoculum was present only in inoculated treatments. Up to 60% of the increased N content of the grain in inoculated plants was potentially derived from nitrogen fixed by the inoculum in the rhizosphere. It was concluded that the most significant result due to inoculation was the consistent maximal increase of N content in grain in inoculated treatments with ammonium sulphate fertiliser at 100 kg N/ha. Inoculation with Burkholderia consistently increased %N in wheat grain, with the potential benefit of decreasing the production cost and reducing use of chemical fertilisers.

In the pig and poultry production industries, energy forms the largest and the greatest cost pressure when a diet is formulated. In Australia, cereal grains such as barley, sorghum, and wheat are the main dietary energy sources, comprising more than 60 % of the diet in many cases. Traditionally, during diet formulation, the energy value of a grain has been represented by a single figure for that particular grain type. However, several studies have indicated that the energy availability from different grains fed to pigs and poultry varies significantly even within one grain cultivar. Given these findings, the use of a single value to represent the energy of each grain type during diet formulation, can lead to inefficient utilisation of dietary resources by animals, and thus decreased animal performance and consequently, a decrease in profit for the pig and poultry production industries. Thus, there is an opportunity to develop a rapid and reproducible in vitro assay to accurately assess the available energy values and nutritional quality of each grain type. In order to develop such an assay, further understanding of factors that affect the available energy values of grains need to be explored. Starch, which is hydrolysed into glucose by animals, is the most abundant energy component in cereal grains, and there is evidence suggesting that variations in digestible or metabolisable energy values may be related to the extent of starch digestibility. For example in poultry, variations in the in vitro digestibility of starch between several wheat cultivars have been shown to correlate with their in vivo available metabolisable energy values. However, it is not known to what extent starch digestibility varies between cultivars of other grain types such as barley and sorghum. There is an increasing body of evidence suggesting that differences in the physical and chemical properties of cereal grains may play an important role in influencing starch digestibility and, consequently, animal performance. Thus, the general hypothesis of this study was that starch digestibility varies between barley, sorghum and wheat, and between cultivars within grain types and this is related to specific chemical and physical characteristics of the grains. To examine this, the following issues were investigated using 18 barley, 15 sorghum and 10 wheat cultivars : 1 ) an in vitro glucose release index ( GRI ) assay was developed to assess starch digestibility within and between the cereal grain types and, 2 ) the GRI was correlated to both starch - related ( e.g., starch content, starch granule size, the amylose to amylopectin ratio, starch gelatinisation properties ) and non - starch - related ( e.g., non - starch polysaccharide composition, kernel hardness, the presence of protein matrix and milling quality ) physical / chemical characteristics within and between the cereal grains. Results revealed significant variations in the GRI both between grains and within a given grain type. The GRI values ranged between 27 - 45 %, 25 - 54 % and 32 - 53 % in barley, sorghum and wheat respectively. Correlation analysis revealed that the GRI in barley, sorghum and wheat was influenced by the physical and chemical characteristics of starch - and non - starch - related grain properties, although the type of characteristic influencing GRI was specific to the grain type. In barley, the ratio of amylose to amylopectin, starch gelatinisation and kernel hardness influenced the GRI. In sorghum, the GRI was influenced by the ratio of amylose to amylopectin, the presence of a protein matrix surrounding starch granules and kernel hardness. Finally in wheat, the presence of protein matrix and milling quality influenced the GRI. It was also shown that the extract viscosity of grains within barley and wheat, but not sorghum, varied significantly. In conclusion, the results from this study indicate that ; 1 ) the GRI assay may be used to identify some factors that affect in vivo starch digestibility within and between barley, sorghum and wheat, 2 ) starch digestibility ( as assessed by the GRI ) may be influenced by some physical and chemical characteristics of cereal grains, and that these characteristics are specific to the type of grain The physical and chemical characteristics that may influence starch digestion will be discussed in relation to their potential physiological effects on energy digestion, and utilisation in animals. The information generated will provide a basis for future studies that will ultimately assist in the design of in vitro assays to predict energy availability from barley, sorghum and wheat grains fed to pigs and poultry, and contribute to the more efficient use of grains in monogastric production systems. / Thesis (Ph.D.)--Department of Animal Science, 2002.

In the pig and poultry production industries, energy forms the largest and the greatest cost pressure when a diet is formulated. In Australia, cereal grains such as barley, sorghum, and wheat are the main dietary energy sources, comprising more than 60 % of the diet in many cases. Traditionally, during diet formulation, the energy value of a grain has been represented by a single figure for that particular grain type. However, several studies have indicated that the energy availability from different grains fed to pigs and poultry varies significantly even within one grain cultivar. Given these findings, the use of a single value to represent the energy of each grain type during diet formulation, can lead to inefficient utilisation of dietary resources by animals, and thus decreased animal performance and consequently, a decrease in profit for the pig and poultry production industries. Thus, there is an opportunity to develop a rapid and reproducible in vitro assay to accurately assess the available energy values and nutritional quality of each grain type. In order to develop such an assay, further understanding of factors that affect the available energy values of grains need to be explored. Starch, which is hydrolysed into glucose by animals, is the most abundant energy component in cereal grains, and there is evidence suggesting that variations in digestible or metabolisable energy values may be related to the extent of starch digestibility. For example in poultry, variations in the in vitro digestibility of starch between several wheat cultivars have been shown to correlate with their in vivo available metabolisable energy values. However, it is not known to what extent starch digestibility varies between cultivars of other grain types such as barley and sorghum. There is an increasing body of evidence suggesting that differences in the physical and chemical properties of cereal grains may play an important role in influencing starch digestibility and, consequently, animal performance. Thus, the general hypothesis of this study was that starch digestibility varies between barley, sorghum and wheat, and between cultivars within grain types and this is related to specific chemical and physical characteristics of the grains. To examine this, the following issues were investigated using 18 barley, 15 sorghum and 10 wheat cultivars : 1 ) an in vitro glucose release index ( GRI ) assay was developed to assess starch digestibility within and between the cereal grain types and, 2 ) the GRI was correlated to both starch - related ( e.g., starch content, starch granule size, the amylose to amylopectin ratio, starch gelatinisation properties ) and non - starch - related ( e.g., non - starch polysaccharide composition, kernel hardness, the presence of protein matrix and milling quality ) physical / chemical characteristics within and between the cereal grains. Results revealed significant variations in the GRI both between grains and within a given grain type. The GRI values ranged between 27 - 45 %, 25 - 54 % and 32 - 53 % in barley, sorghum and wheat respectively. Correlation analysis revealed that the GRI in barley, sorghum and wheat was influenced by the physical and chemical characteristics of starch - and non - starch - related grain properties, although the type of characteristic influencing GRI was specific to the grain type. In barley, the ratio of amylose to amylopectin, starch gelatinisation and kernel hardness influenced the GRI. In sorghum, the GRI was influenced by the ratio of amylose to amylopectin, the presence of a protein matrix surrounding starch granules and kernel hardness. Finally in wheat, the presence of protein matrix and milling quality influenced the GRI. It was also shown that the extract viscosity of grains within barley and wheat, but not sorghum, varied significantly. In conclusion, the results from this study indicate that ; 1 ) the GRI assay may be used to identify some factors that affect in vivo starch digestibility within and between barley, sorghum and wheat, 2 ) starch digestibility ( as assessed by the GRI ) may be influenced by some physical and chemical characteristics of cereal grains, and that these characteristics are specific to the type of grain The physical and chemical characteristics that may influence starch digestion will be discussed in relation to their potential physiological effects on energy digestion, and utilisation in animals. The information generated will provide a basis for future studies that will ultimately assist in the design of in vitro assays to predict energy availability from barley, sorghum and wheat grains fed to pigs and poultry, and contribute to the more efficient use of grains in monogastric production systems. / Thesis (Ph.D.)--Department of Animal Science, 2002.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed June 17, 2008). PDF text: xiii, 152 p. : ill. (some col.) ; 2 Mb. UMI publication number: AAT 3293917. Includes bibliographical references. Also available in microfilm and microfiche formats.