Agricultural Change and Farmland Rental in an Urbanising Environment : Waterloo Region, Southern Ontario

Dans l'analyse des rapports entre l'urbanisation et l'agriculture, la recherche géographique s'est surtout intéressée, jusqu'à maintenant, aux effets néfastes de la croissance urbaine sur l'agriculture. Nous émettons l'idée que cette interaction, lorsque prévalent des conditions régionales bien précises, peut jouer un rôle positif dans le progrès agricole. C'est à titre d'exemple d'effets potentiellement bénéfiques que nous étudions ici le phénomène de la location des terres agricoles appartenant à des propriétaires non-exploitants. Pour une région donnée du sud de l'Ontario, des corrélations statistiques entre certaines variables agricoles et démographiques justifient une enquête approfondie auprès des agriculteurs. Les résultats de cette enquête montrent, qu'autour des villes de taille moyenne à haut niveau de croissance de cette région, la location des terres appartenant à des non-exploitants joue un rôle important dans le développement agricole. Cette recherche contribue donc à alimenter une littérature récente qui tend à démontrer la complexité de l'agriculture en milieu péri-urbain.In geographic research into urbanisation-agriculture interactions, a strong emphasis has been given to the negative effects of urbanisation on agriculture. Here, it is argued that the urbanisation-agriculture interaction process may provide certain opportunities for agricultural progress and development, depending upon the specific regional circumstances; the phenomenon of farmland renting from nonfarm landowners is thus studied as an example of such a potentially beneficial interaction. Statistical associations between agricultural and population variables for an area in southern Ontario provide the context for a detailed farmer survey. The results show farmland rental from nonfarm owners to be a significant factor in agricultural development in the urban fringe environment of the medium-sized, yet fast-growing cities in the study area, and add to recent literature which has stressed the complexities of urban fringe agriculture

A change in temperature modulates defence to yellow (stripe) rust in wheat line UC1041 independently of resistance gene Yr36

Background Rust diseases are of major importance in wheat production worldwide. With the constant evolution of new rust strains and their adaptation to higher temperatures, consistent and durable disease resistance is a key challenge. Environmental conditions affect resistance gene performance, but the basis for this is poorly understood. Results Here we show that a change in day temperature affects wheat resistance to Puccinia striiformis f. sp tritici (Pst), the causal agent of yellow (or stripe) rust. Using adult plants of near-isogenic lines UC1041 +/- Yr36, there was no significant difference between Pst percentage uredia coverage in plants grown at day temperatures of 18°C or 25°C in adult UC1041 + Yr36 plants. However, when plants were transferred to the lower day temperature at the time of Pst inoculation, infection increased up to two fold. Interestingly, this response was independent of Yr36, which has previously been reported as a temperature-responsive resistance gene as Pst development in adult UC1041 -Yr36 plants was similarly affected by the plants experiencing a temperature reduction. In addition, UC1041 -Yr36 plants grown at the lower temperature then transferred to the higher temperature were effectively resistant and a temperature change in either direction was shown to affect Pst development up to 8 days prior to inoculation. Results for seedlings were similar, but more variable compared to adult plants. Enhanced resistance to Pst was observed in seedlings of UC1041 and the cultivar Shamrock when transferred to the higher temperature. Resistance was not affected in seedlings of cultivar Solstice by a temperature change in either direction. Conclusions Yr36 is effective at 18°C, refining the lower range of temperature at which resistance against Pst is conferred compared to previous studies. Results reveal previously uncharacterised defence temperature sensitivity in the UC1041 background which is caused by a change in temperature and independently of Yr36. This novel phenotype is present in some cultivars but absent in others, suggesting that Pst defence may be more stable in some cultivars than others when plants are exposed to varying temperatures

Christopher R. Pauley in a Senior Recital

This is the program for the senior voice recital of Christopher R. Pauley, accompanied by Patti Bryant on piano and Cynthia Miles on the French horn. The recital was held on March 20, 1990, in the Mabee Fine Arts Center Recital Hall

Freeform Deposition Method for Coolant Channel Closeout

A method is provided for fabricating a coolant channel closeout jacket on a structure having coolant channels formed in an outer surface thereof. A line of tangency relative to the outer surface is defined for each point on the outer surface. Linear rows of a metal feedstock are directed towards and deposited on the outer surface of the structure as a beam of weld energy is directed to the metal feedstock so-deposited. A first angle between the metal feedstock so-directed and the line of tangency is maintained in a range of 20-90.degree.. The beam is directed towards a portion of the linear rows such that less than 30% of the cross-sectional area of the beam impinges on a currently-deposited one of the linear rows. A second angle between the beam and the line of tangency is maintained in a range of 5-65 degrees