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| Registros recuperados: 35 | |
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| Islam, Q.; Mullen, John D.; Brennan, John P.; Li, G.D.; Helyar, K.R.; Jones, Randall E.. |
| Acid and acidifying soils occur extensively in Australia. Currently, some 90 million hectares of agricultural land in Australia is considered to be acidic and around 35 million hectares are considered to be highly acidic which is both a serious agricultural and environmental problem. The nature, impact, and causes of soil acidification vary across Australia, as do farming systems and the institutional and socioeconomic issues relating to land management. In high-rainfall areas of south-eastern Australia, managing acid soils is particularly difficult in permanent pasture systems. In this paper, an economic analysis is made of the results of a long-term trial (MASTER – Managing Acid Soils Through Efficient Rotations) aimed at developing a sustainable... |
| Tipo: Presentation |
Palavras-chave: Soil acidity/pH/amelioration/farming/rotations/gross margin/stocking rates; Crop Production/Industries; Farm Management. |
| Ano: 1999 |
URL: http://purl.umn.edu/123818 |
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| Brennan, John P.; Bialowas, Adam. |
| A study was made of the changes from 1965 to 1997 in wheat varieties grown in selected shires representing farming systems across NSW. The eight shires examined were Wagga, Temora, Cowra, Carrathool, Lachlan, Coonabarabran, Gunnedah and Narrabri. In each shire, approximately 8-10 varieties were grown each year. Generally, three of those varieties were grown on a substantial proportion of the area; the minor varieties were either new varieties in the process of being built up to their peak adoption or older varieties in the stage of being replaced. In southern shires, there has been a tendency to reduce the number of varieties grown, while in the northern shires the number of varieties grown has increased since 1965. The progress of breeders in developing... |
| Tipo: Report |
Palavras-chave: Production Economics. |
| Ano: 2001 |
URL: http://purl.umn.edu/28003 |
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| Brennan, John P.; Godden, David P.; Smale, Melinda; Meng, Erika C.H.. |
| As part of an ACIAR-funded project on genetic diversity in wheat in Australia and China, Australian wheat breeders were surveyed to assess the importance of genetic diversity to breeders. This paper reports the findings of that survey, and identifies the key issues that concern wheat breeders. The issues addressed include the breeders’ attitude to diversity and the diversity available in their current gene pool. The sources of materials that breeders use to maintain and/or increase diversity in their programs are identified, and ways in which diversity influences breeding decisions are also examined. More importantly from the policy view point, survey responses identify changes over time in the environment in which breeders operate that affect the extent... |
| Tipo: Presentation |
Palavras-chave: Genetic/diversity/wheat/breeder/survey; Crop Production/Industries. |
| Ano: 1999 |
URL: http://purl.umn.edu/123776 |
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| Smale, Melinda; Meng, Erika C.H.; Brennan, John P.; Hu, Ruifa. |
| Spatial diversity indicators may serve policymakers as they seek to manage crop genetic diversity and externalities associated with diffusion of some genetically modified crops. This paper adapts ecological indices of spatial diversity to area distributions of modern wheat varieties in contrasting production systems of Australia and China. The variation in three concepts of spatial diversity—richness, abundance, and evenness—is explained using Zellner’s seemingly unrelated regression (SUR). Determinants of wheat diversity differ by concept, but include variety traits other than yield potential, environmental factors, and policies affecting the supply of varieties, research spill-ins, and market liberalization. |
| Tipo: Presentation |
Palavras-chave: Agricultural and Food Policy; Crop Production/Industries. |
| Ano: 2000 |
URL: http://purl.umn.edu/123732 |
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| Brennan, John P.. |
| Wheat genetic materials developed from research at the International Maize and Wheat Improvement Center (CIMMYT) in Mexico for developing countries have provided spillover benefits to Australia. Varieties developed from those genetic materials have resulted in yield increases in Australia. While the initial impact came through the introduction of higher-yielding semi-dwarf wheat crops, those impacts have continued in the post-semidwarf period. CIMMYT’s success in developing countries has also reduced the world price for wheat. While the lower prices affect returns in Australia, the increased yields in Australia from the CIMMYT spillovers from both the semi-dwarfs and the postsemidwarf phases have provided benefits to Australia averaging A $30 million per... |
| Tipo: Article |
Palavras-chave: R&D evaluation; R&D policy; Spillovers; Technology adoption; Crop Production/Industries; Research and Development/Tech Change/Emerging Technologies. |
| Ano: 2007 |
URL: http://purl.umn.edu/118519 |
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| Brennan, John P.; Singh, Rajinder Pal; Bialowas, Adam. |
| Feed grains researchers have abundant technical opportunities to select various options for improvement of nutritional characteristics of feed grains. Choosing between those opportunities is a difficult issue for research funding organisations. In this paper, efforts to address the relative economic benefits from the different options for feed grains nutritional improvement are reported. The economic benefits arising from nutritional improvements in various feed grains are examined and compared to the benefits from increasing yields of the feed grains rather than improving their nutritional value. The results of the analysis of these options are presented in an economic surplus framework that enables the major beneficiaries and the relative gains for the... |
| Tipo: Presentation |
Palavras-chave: Research; Feed grain; Nutrition; Value; Crop Production/Industries; Food Consumption/Nutrition/Food Safety. |
| Ano: 2000 |
URL: http://purl.umn.edu/123608 |
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| Brennan, John P.; Godden, David P.; Smale, Melinda; Meng, Erika C.H.. |
| Genetic diversity in agricultural systems relies on both the supply of diversity through varieties produced by breeding programs, and the demand for that diversity, through farmers' usage of varieties. Variety choice by farmers is demonstrated through the mix of varieties that is grown in a given region. In this paper, the conceptual issues relating to the supply of and demand for genetic diversity are explored. An empirical analysis of the varietal demand, based on the varieties grown in the Temora Shire in southern NSW over the post-War period, is undertaken. Changes over time in the choice of varieties by farmers are analysed, and some implications for genetic diversity are discussed. |
| Tipo: Presentation |
Palavras-chave: Genetic/diversity/wheat/variety/demand/growers; Crop Production/Industries. |
| Ano: 1999 |
URL: http://purl.umn.edu/123785 |
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| Brennan, John P.; Kingwell, Ross S.; Thomson, Fiona M.; Cullis, Brian R.. |
| In undertaking cultivar trials, the variability of the response of the cultivars to the different environments in which they are grown introduces the possibility of release errors and non‐release errors in the decisions made on the basis of the trial results. In this article a model is developed that accounts for the economic costs of those errors as well as the costs of operating the trials, and enables the features of the optimal cultivar testing program to be identified. The model is illustrated by application to wheat cultivar trials in central and southern NSW. |
| Tipo: Journal Article |
Palavras-chave: Crop Production/Industries. |
| Ano: 1998 |
URL: http://purl.umn.edu/117231 |
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| Brennan, John P.. |
| An evaluation of the contribution of wheat breeding to increasing yields on farms can be accomplished by an examination of the effect on farm production of changes in varieties and other inputs using a production function. Three different means of representing the effect of varietal change in a production function are identified, and the advantages and limitations of these are discussed. An empirical analysis of each is presented for the Mitchell Shire in southern N.S.W. The evidence suggests that the different measures are not highly correlated, so the choice between them can be critical to the results obtained from a full examination in a production function. |
| Tipo: Journal Article |
Palavras-chave: Crop Production/Industries. |
| Ano: 1984 |
URL: http://purl.umn.edu/12281 |
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| Smale, Melinda; Meng, Erika C.H.; Brennan, John P.; Hu, Ruifa. |
| Spatial diversity indicators may serve an important function for policymakers as they seek to manage crop genetic diversity and potential externalities associated with diffusion of some types of genetically improved crops. This paper adapts spatial diversity indices employed by ecologists in the study of species diversity to area distributions of modern wheat varieties in contrasting production systems of Australia and China. The variation in three interrelated concepts of diversity "richness, abundance, and evenness" is explained by factors related to the demand and supply of varieties, agroecology, and policies using the econometric method of Zellner's seemingly unrelated regression (SUR). Results suggest that in addition to expected yield and... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Crop Production/Industries. |
| Ano: 1999 |
URL: http://purl.umn.edu/7697 |
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| Brennan, John P.; Singh, Rajinder Pal; Singh, Inder Pal. |
| Researchers have abundant technical opportunities to select various options for improvement of nutritional characteristics of feed grains. Choosing between those opportunities is a difficult issue for research funding organisations. In this paper, an attempt to address those research resource allocation issues is reported. The approach to use in analysing improvements in the feed quality of grains is discussed. By defining the problem as a cost reduction for the livestock industries, the impact of improvements in grain nutrition can be defined by their impact on the least-cost feed rations for different livestock categories. Using that approach, the benefits of improved feeds can be evaluated, and research priorities can be determined on the basis of which... |
| Tipo: Presentation |
Palavras-chave: Feed grain; Nutrition; Value; Research; Crop Production/Industries. |
| Ano: 1999 |
URL: http://purl.umn.edu/123789 |
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| Registros recuperados: 35 | |
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