A growing world population drives an ever-increasing need for food and energy. These challenges, along with depletion of water and fossil fuel resources, call for improvements in crop production systems and the cultivars used within them. Perennial cropping systems present an attractive solution to many of these problems. A greater understanding of the genetic control of over-wintering ability within crop species is one way to begin the process of making perennial cropping systems a possibility. In this study an F3:F4 family derived from a cross between Sorghum bicolor (L.) Moench and S. propinquum (Kunth) Hitchc. segregating for rhizome production was phenotyped in both field and greenhouse environments for traits relating to rhizomatousness and over-wintering. Several statistical models were created to correlate rhizome growth and over-wintering. A known rhizome quantitative trait locus (QTL) region was saturated with SSR markers and the QTL interval was reduced from previous estimates of about 16 Mb or 7 cM to 12 Mb or 2 cM, a 25% or 71% reduction in physical or linkage distance respectively. Two previously unidentified QTL regions associated with over-wintering were also identified. Our results also support the hypothesis that rhizome growth is important and possibly necessary for over-wintering in Sorghum.

Bactrocera tryoni, the Queensland fruit fly, is established along the entire Australian east coast. It is a major pest of horticulture and arguably the worst horticultural insect pest in Australia. Adult flies lay eggs into fruit and resultant larvae feed on the flesh of the fruit. The population biology of B. tryoni has been well studied in temperate regions, where it has been established that climatic factors, particularly temperature and rainfall, limit population growth. In contrast, in subtropical and tropical regions, the population dynamics of the fly have been little studied. This thesis investigates the fly's phenology and abundance changes across subtropical and tropical Queensland and asks what factors govern the population cycles of B. tryoni in this state. Winter breeding and abundance of the fly, a component of the seasonal cycle which in south-east Queensland is fundamentally different from that observed in temperate Australia, is also investigated. A historical, extensive multi-year and multi-site trapping data set with from across Queensland was analysed to look at the effects of temperature, rainfall and relative humidity on B. tryoni trap catch. Trap data was further compared with the predicted phenology data generated by a DYMEX® based B. tryoni population phenology model. The phenology model used was based on a previously published model, but was also modified to more explicitly look at the effects of host plant availability and the presence or absence of non-reproductive over-wintering flies. Over-wintering field cage studies and a winter-spring field trapping study, both carried out in Brisbane, supplied additional data on B. tryoni's population abundance and capacity to breed during winter in the subtropics. Results show significant variation of monthly fly abundance for nine sites across Queensland. Abundance changed across sites in non-predictable ways. Annual population phenology within a site was, for some sites, highly consistent from year to year, but inconsistent for other sites. All sites in the subtropics showed some form of population depression during the cooler months, but breeding was continuous, albeit reduced at nearly all sites. Some tropical sites, where the climate is regarded as highly favourable for B. tryoni, still showed dramatic peaks and troughs in annual population abundance. There were relatively few significant correlations observed between weather factors and fly populations for any site. Output from the DYMEX population model suggested that fruit availability is a major driver of population dynamics in the tropical north of the state, while weather is more important in the subtropical south. The population dynamics of B. tryoni at sites along the central Queensland coast, where it is assumed that a mix of both weather and host fruit availability drive local populations, were poorly captured by the population model. Field cage results showed that B. tryoni successfully bred during winter in Brisbane, with pupal emergence starting in mid-winter (1st week of August), peaking in early spring (2nd week of September). Trap catch at orchards in Brisbane increased with increasing temperature and fruit availability, but diminished with decreasing temperature and fruit availability. The results suggest that B. tryoni has an optimal climate for population growth in the tropics, but fruit availability for offspring production limits population growth. In the subtropics however, both climate and fruit availability determine the population size. Winter temperatures are marginal for B. tryoni population growth in the subtropics.

Lauko eksperimentai atlikti 2009 – 2010 m. Lietuvos žemės ūkio universiteto bandymų stotyje, kur dirvožemis yra karbonatingas sekliai glėjiškas išplautžemis (Calc(ar)i-Epihypogleyic Luvisol). Mūsų tyrimo tikslas buvo nustatyti žieminių rapsų sėjos laiko poveikį rudens skrotelės cheminei sudėčiai ir augalų peržiemojimui. Skirtingu laiku sėtų žieminių rapsų skrotelės cheminė sudėtis turėjo įtakos augalų žiemojimui – tarp šių požymių buvo nustatyti įvairaus stiprumo statistiškai patikimi priklausomumai. Linijinės ‘Sunday‘ veislės rapsų skrotelės cheminė sudėtis stipriau įtakojo peržiemojimo proc., palyginus su hibridine ‘Kronos‘ veisle. Geriau peržiemojo hibridinės veislės rapsai (ypač sėti vėliau) – 39,2–77,0 proc. augalų, negu linijinės veislės – 12,8–54,0 proc. Geriausia žieminiai rapsai peržiemojo sėti rugpjūčio 30 - rugsėjo 5. Jie lapuose sukaupė 15,23-18,14% sausųjų medžiagų, 4,61-5,69% bendrojo cukraus, N ir K santykis lapuose buvo 1,64-1,76. Viršūniniame pumpure – 18,01-19,68% sausųjų medžiagų, 6,00-8,49% bendrojo cukraus, N ir K santykis buvo 1,49-1,69 ir šaknyse – 17,46-18,37% sausųjų medžiagų, 7,71-10,30% bendrojo cukraus, N ir K santykis buvo 1,05-1,56. Hibridinės veislės rapsai, ypač sėjant juos vėliau, intensyviau ruošiasi žiemojimui. Rapsų peržiemojimas priklausė nuo skrotelės cheminės sudėties: sausųjų medžiagų ir bendrojo cukraus kiekio, bei nuo N ir K santykio. / The experiment carried out in the Experimental Station of Lithuanian University of Agriculture in 2009 – 2010. The soil is shallow calcareous Luvisols (Calc(ar)i-Epihypogleyic Luvisol). The aim of our investigation was to determine the effect of sowing time of winter oilseed rape on autumn rosette chemical composition and over-wintering. Chemical composition of rossete of winter rape sown at different time influenced crop over-wintering – significant correlation between this indicators was established. The stronger influence of the winter rape rosette composition on over-wintering was established in rape of linear cultivar ‘Sunday‘ than in rape of hybrid cultivar ‘Kronos‘.Winter rape of hybrid cultivar over-wintered better – 39, 2–77,0%, winter rape of linear cultivar – 12,8–54,0%. Winter rape sown on 30 August – 5 September best over-wintered. They acumulated 15,23–18,14% of dry matter, 4,61–5,69% of total sugar, N and K ratio was 1,64–1,76 in leaves, and in apical bud – 18,01–19,68% of dry matter, 6,00–8,49% of total sugar, N and K ratio was 1,49–1,69 and in roots – 17,46-18,37% of dry matter, 7,71-10,30% of total sugar, N and K ratio was 1,05-1,56. Winter rape of hybrid cultivar sown at later dates prepared for over-wintering more intensively. Winter rape of both cultivars sown at the latest date not over-wintered. Over-wintering depended winter rape rosette on the chemical composition: dry matter and total sugar content, and the N and K ratio.

Seabirds are wide-ranging apex-predators and useful bio-indicators of marine systems. Nevertheless, changes are occurring in the marine environment, and seabirds require protection from the deleterious effects of climate change, fisheries, pollution, offshore development, introduced predators and invasive species. The UK supports internationally important populations of seabirds but also has vast wind and wave resources, therefore understanding how seabirds use the marine environment is vital in order to quantify the potential consequences of further exploiting these resources. In this thesis I first describe the range of wave energy converting devices operational or in development in the UK, and review the potential threats and benefits these developments may have for marine birds. I then synthesise data from colony-based surveys with detailed information on population dynamics, foraging ecology and near-colony behaviour, to develop a projection model that identifies important at-sea areas for breeding seabirds. These models show a positive spatial correlation with one of the most intensive at-sea seabird survey datasets, and provide qualitatively similar findings to existing tracking data. This approach has the potential to identify overlap with offshore energy developments, and could be developed to suit a range of species or whole communities and provide a theoretical framework for the study of factors such as colony size regulation. The non-breeding period is a key element of the annual cycle of seabirds and conditions experienced during one season may carry-over to influence the next. Understanding behaviour throughout the annual cycle has implications for both ecological theory and conservation. Bio-logging can provide detailed information on movements away from breeding colonies, and the analysis of stable isotope ratios in body tissues can provide information on foraging during the non-breeding period. I combine these two approaches to describe the migration strategies of northern gannets Morus bassanus breeding at two colonies in the north-west Atlantic, revealing a high degree of both winter site fidelity and dietary consistency between years. These migratory strategies also have carry-over effects with consequences for both body condition and timing of arrival on the breeding grounds. Finally, I investigate the threats posed to seabirds and other marine predators during the non-breeding period by collating information on the distributions of five different species of apex predator wintering in the Northwest African upwelling region. I describe the threat of over-fishing and fisheries bycatch to marine vertebrates in this region, and highlight the need for pelagic marine protected areas to adequately protect migratory animals throughout the annual cycle. In summary, the combination of colony-based studies, bio-logging, stable isotope analysis and modelling techniques can provide a comprehensive understanding of the interactions between individuals and the marine environment over multiple spatial and temporal scales.

This thesis was conducted to evaluate important epidemiological features of Gastro-Intestinal Nematode (GIN) infections in Ontario sheep flocks; namely, the PeriParturient Egg Rise (PPER), overwintering of GIN free-living stages on pasture, and Anthelmintic Resistance (AR). Three main studies were carried out: a longitudinal study was conducted on six sheep farms to evaluate the PPER in ewes lambing in different seasons and to determine whether total plasma protein (TPP) levels and packed cell volume (PCV) were associated with increased fecal GIN-egg shedding. Secondly, a pilot-study was conducted on three farms to describe pasture-level environmental conditions and over-wintering survival and infectivity of free-living GIN larvae, especially Haemonchus contortus. Lastly, a cross-sectional study was conducted on 47 sheep farms in Ontario, to evaluate the frequency of AR, compare different diagnostic tests for AR, and evaluate management practices associated with AR. In the longitudinal study, the PPER was observed in winter, spring and autumn lambing ewes, though the magnitude and distribution of the PPER varied with season. Lower TPP and PCV values were associated with increased fecal GIN-egg counts. The pilot-study suggested that H. contortus larvae did not overwinter successfully on pasture, while other GINs, such as Teladorsagia sp., Trichostrongylus spp. and Nematodirus spp., were able to overwinter on pasture, and were infective the following spring. Resistance to ivermectin, fenbendazole and levamisole was demonstrated on 97% (28/29), 95% (19/20) and 6% (1/17) respectively of the farms tested; most of the resistance observed was found in Haemonchus sp. The Fecal Egg Count Reduction percentage following treatment was influenced by which mean (i.e. arithmetic vs. geometric) was used in the formula; use of pre-treatment in addition to post-treatment faecal egg counts was not influential. Both the fecal egg count reduction test and the larval development assay diagnosed resistance, but there was poor agreement between the two tests, as indicated by the Kappa test. The prior use of benzimidazoles on farms was associated with higher levels of fenbendazole resistance. The information generated in this thesis will be used to develop a parasite control program for sheep flocks in Ontario and to guide future research on GIN parasitism. / New Directions - Ontario Ministry of Agriculture, Food and Rural Affairs; Ontario Sheep Marketing Agency; Ontario Agriculture Centre Canada; Merial; Animal Health Strategic Initiative - University of Guelph Partnership; Undergraduate Research Assistantship; Gartshore Memorial Sheep Scholarship;

Viticultural practices such as trunk girdling and shoot topping along with defoliation, shading and node number per vine treatments were used to alter the carbohydrate physiology of mature Chardonnay grapevines growing in the cool climate of Canterbury, New Zealand. The timing of vine defoliation in the season previous to fruiting decreased concentrations of over-wintering carbohydrate reserves (mostly starch) in both the trunks and roots of grapevines. Roots were particularly sensitive, with defoliation as early as 4 weeks after bloom in the previous season reducing starch concentrations to 1.5%Dwt at bud burst compared with 17%Dwt in non-defoliated vines. In contrast, partial vine defoliation as early as bloom in the previous season reduced root starch concentrations to 4-7%Dwt at bud burst compared with 15%Dwt in non-defoliated vines. Vine shading and trunk girdling treatments at bloom in the previous season, resulted in small reductions in root starch concentrations (16%Dwt) compared with non-shaded and non-girdled vines (19%Dwt), but shoot topping did not. Study across three growing seasons established that higher concentrations of over-wintering trunk and root carbohydrate reserves were associated with warmer and sunnier weather in the previous growing season. Individual shoot leaf removal at either the beginning or towards the end of the inflorescence initiation period, reduced shoot starch concentrations to 3-6%Dwt compared with 11 %Dwt for no leaf removal, such reductions persisted through to the following season. Shoot topping at the start of the initiation period had no effect on shoot carbohydrate accumulation, but trunk girdling temporarily increased shoot starch concentrations during the first 31 days after treatment. Reductions in over-wintering trunk and root carbohydrate reserves were associated with a reduction in inflorescences per shoot and flowers per inflorescence in the following season, the reduction as much as 50% compared with non carbohydrate stressed vines. While there were strong linear or curvilinear relationships between the concentration of starch in trunks and roots at bud burst and inflorescences per shoot and flowers per inflorescence, in case the of inflorescences per shoot, there was not an immediate cause and effect because inflorescences were initiated in the previous season. Individual shoot leaf removal during the inflorescence initiation period illustrated that leaf removal directly inhibited the initiation of inflorescences in latent buds. Shoot carbohydrate measurements showed a strong curvilinear relationship to the number of inflorescences per shoot, with a threshold starch concentration of 10-12%Dwt during the inflorescence initiation period required for a maximum number of inflorescences per shoot. Furthermore, examination of individual node positions emphasised the importance of the subtending leaf on the initiation of inflorescences within the latent bud. The number of inflorescences per shoot post bud burst was reduced on vines that were both carbohydrate reserve stressed (by previous season's defoliation) and had a high node (108) number retained per vine after winter pruning compared with little or no reduction in inflorescences per shoot on carbohydrate reserve stressed vines that had a low (20) node number per vine. The reduction in inflorescences per shoot on high node vines was associated with reduced carbohydrate reserves and reduced shoot vigour (thinner and lighter shoots). Flowers per inflorescence were reduced by as much 50% in response to lower overwintering carbohydrate reserves. Fewer flowers per inflorescence were attributed to a reduction in primary branching of the inflorescence and also a reduction in flowers per branch. Strong linear relationships between the concentrations of starch in trunks and roots and flowers per inflorescence indicate that the determination of flowers per inflorescence, unlike inflorescences per shoot, may be dependent on the level of overwintering carbohydrate reserves. This is most likely due to changes in branching of the inflorescence and individual flower formation occurring during the bud burst period. Per cent fruitset was not affected by reductions in carbohydrate reserves, so fewer inflorescences per shoot and flowers per inflorescence resulted in reduced vine yield. The findings of this thesis indicate that changes in the level of carbohydrate production and partitioning in response to a range of viticultural management practices and seasonal weather contribute to seasonal variation in grapevine flowering and yields in New Zealand's cool climate environment. The relationships between carbohydrate reserves and flowering illustrate the potential to use this information to predict grapevine flowering and forecast yields. The practical implications of this research illustrate that the viticulturist must manage grapevines not only for the current crop, but also for subsequent crops by maintaining sufficient carbohydrate reserves for balanced growth flowering and fruiting from season to season.