[Typescript] Includes bibliography.

Exclosure plots were monitored to investigate the impact of browsing on seedling recruitment by Trichosurus vulpecula, Oryctolagus cuniculus and Rattus rattus on seedlings under Leptospermum scoparium and Kunzea ericoides plantings in two Auckland Regional Council Parks (ARC), Shakespear and Wenderholm. The number of woody seedlings that established over a 17-month period was recorded. Gaps within the same Leptospermum scoparium and Kunzea ericoides canopy were created to investigate the influence of the canopy on seedling recruitment. Soil samples were taken to investigate the existing seed bank beneath the same Leptospermum scoparium and Kunzea ericoides canopies.At Wenderholm, net change in seedling density differed among treatments (P=0.014). Seedling density increased within the plots that excluded Trichosurus vulpecula and Oryctolagus cuniculus and within plots that additionally excluded Rattus rattus, but declined in the control plots. In contrast at Shakespear, although seedling density increased more within both the exclosure plots than in the control plots, this result was not statistically significant (P=0.728). At Wenderholm, the average seedling height increased within both types of exclosure plots, but declined in the control plots. However, these differences among treatments were not statistically significant (P=0.204). At Shakespear, seedlings increased in height within the Trichosurus vulpecula, Oryctolagus cuniculus and Rattus rattus exclosures and declined marginally in the other two treatments. Again, differences in height change among treatments were not statistically significant (P=0.202).At both regional parks, the greatest cause of mortality within the exclosures excluding Trichosurus vulpecula and Oryctolagus cuniculus was desiccation. All of the mortalities within the Trichosurus vulpecula, Oryctolagus cuniculus and Rattus rattus exclosures was unidentifiable. However, within the control plots, at Wenderholm, the greatest identified cause of mortality was browsing and at Shakespear, the only cause of mortality within the control plots was browsing.Seedbanks at Wenderholm and Shakespear under the Leptospermum scoparium and Kunzea ericoides plantings were dominated by forb species. A total of 1308 seedlings germinated from soil taken from Wenderholm, with exotic species making up 99.4% of germinations, with exotic species making up 97.9% of germinations. Similarly a total of 801 seedlings germinated from soil samples taken from Shakespear.At Wenderholm, the number of native seedling germinations within the gaps created in the Leptospermum scoparium and Kunzea ericoides canopy, was more than twice the number that germinated under the closed canopy. However, this difference was marginally non-significant (P=0.065). At Shakespear, the number of native seedling germinations within gaps created in the Leptospermum scoparium and Kunzea ericoides canopy was similar to the number that germinated under the closed canopy (P=0.2603).The results suggest that at Wenderholm, despite ongoing predator control, Trichosurus vulpecula and/or Oryctolagus cuniculus have had an adverse effect on the survival and growth of seedlings. The results also suggest that at Shakespear, Rattus rattus have had an adverse effect on the survival and growth of seedlings under the Leptospermum scoparium and Kunzea ericoides canopy. The distance from mature forest may also have had an impact on the dispersal of native seeds within the Leptospermum scoparium and Kunzea ericoides canopy. The implication of these results for the future management of restoration plantings in regional parks is discussed.

Bibliography: p. 182-197. The objectives of this study are: selection and construction of four narrow sowing points, evaluation of these points in terms of draught requirements and wear rates, comparison of the points in direct drilling systems and their effects on soil physical properties.

The developmental programs of maturing seed and fruit in pea (Pisum sativum L.) are tightly controlled by the interactions of several phytohormones, including gibberellins (GAs), auxins, and abscisic acid (ABA). To more fully understand these hormone networks and their roles in controlling development, transcription profiles of GA metabolism genes and metabolite profiles of key GAs, auxins, and ABA were determined in developing seeds, and histological studies were employed to correlate physiology and hormone metabolism. Data suggest that bioactive GA stimulates several aspects of seed growth, and ABA appears to promote bioactive GA1 synthesis in rapidly growing seed coats, and inhibit GA biosynthesis in the embryo axes of maturing embryos. Two putative auxin receptor genes were cloned, and their transcription profiles examined in developing seed and pericarp tissues. Pericarp PsAFB6A transcription was responsive to auxin and seed signals, indicating a potential role for the modulation of auxin sensitivity in fruit development.

Kura clover (Trifolium ambiguum) is a perennial legume species that has been found to have exceptional persistence in the United States, Australia and New Zealand. There are two challenges that impede the incorporation of Kura clover into pasture mixtures in Alberta. The first is the lack of available seed, and the second is poor establishment success in mixtures with highly competitive grass species. A series of experiments were conducted to (i) address the potential for seed production in a central Alberta environment and (ii) to determine alternative strategies for establishment in mixtures. Kura clover successfully flowered and produced seed under central Alberta growing conditions. Seed production was greater from the cultivar Endura than Cossack. Kura clover seed production was not affected by row spacing however, yield was greater when clover was planted at 3 or 6 kg/ha versus 9 or 12 kg/ha. Seed yield ranged from 80 kg/ha to 350 kg/ha. Establishing Kura clover with a cover crop reduced flowering and seed production. Corn (Zea mays) was the least competitive cover crop, followed by faba bean (Vicia faba L.). Canola (Brassica napus), peas (Pisum sativum L.), barley (Hordeum vulgare) and triticale (X Tritosecale) reduced Kura clover seed yield and are not recommended as cover crops. Comparison of above and below ground competition between Kura clover and meadow bromegrass (Bromus biebersteinii), indicated that below ground competition has the greatest impact on Kura clover seedling growth. Altering seeding rate and delaying introduction of the grass species by up to two months significantly improved Kura clover establishment in mixtures. Kura clover survival in established pastures was higher with physical than chemical sod suppression of the standing forage. Dry matter yield of Kura clover was greatest when defoliated at 6 week intervals. Challenges still remain regarding seed production and establishment of Kura clover. However, we successfully addressed the major concerns regarding the potential of Kura clover in Alberta. / Plant Science

Flax (Linum usitatissimum L.) is considered as a model plant species for multipurpose uses with whole plant utilization for several purposes including industril, food, animal feed, fiber, nutraceutical, pharmaceutical, and bioproduct markets. Therefore, flax is in the process of genetic engineering to meet the market requirements. Prior to commercial release of genetically engineered (GE) flax, a risk assessment was conducted to determine intra- and inter-specific pollen-mediated gene flow and for quantifing and mitigating the adventitious presence (AP) of volunteer flax in canola (Brassica napus L.). The results of pollen-mediated gene flow study (crop-to-crop) suggest that about 1.85% outcrossing would occur in adjunct area, when two flax cultivars were grown in close proximity of 0.1 m apart. Some rare gene flow events were recorded maximum up to 35 m distance from the pollen source but at a very low frequency. The genus Linum has several wild and weedy species, distributed in many parts of the world. A meta-analysis was conducted to determine the potential for gene introgression from GE flax to wild relatives, the occurrence, the phylogeny of flax wild relatives and reported interspecific hybridization. The results demonstrated that cultivated flax has ability to hybridize and form viable F1 plants with at least nine species of Linum; however, none of these species have been reported to occur in Canada. Hybridization of flax with many other wild relatives has either not been studied or reported. However, based on the evidence of reported work, gene flow from GE flax to wild or weedy relatives may occur elsewhere depending on species distribution, sympatry, concurrent flowering, ploidy level and sexual compatibility. The results of the experiments to mitigate the adventitious presence of flax volunteers in canola suggest that combinations of pre-plant followed by post-emergence herbicides were most effective for reducing volunteer flax density and AP in glufosinate-resistant canola. Post-emergence application of imazamox+imazethapyr, however, was not effective for controlling volunteer flax in imidazolinone-resistant canola. Best management practices were developed to mitigate transgene movement from GE flax to ensure co-existance of GE, conventional and organic flax without market harm. / Plant Science

<i>Festuca hallii</i> [(Vasey) Piper] (plains rough fescue) is a dominant native grass species in the Fescue Prairie region of North America that has undergone dramatic range reduction in the past century. This research is undertaken to address the related issues associated with the effectiveness of sampling in capturing genetic diversity, the influence of habitat fragmentation on genetic variation, the geographic variation of seed germination characteristics, and the comparative genetic variation of differential germination. It was found that the tiller samples revealed slightly larger among-population variation than the seed samples. The fescue plant was genetically diverse, as revealed by the proportion of polymorphic bands, the mean band frequency, and the within-population variation. The genetic variation was not highly differentiated with only 6.5% of the total AFLP variation residing among populations. Mantel test revealed a significant correlation between genetic and geographic distances and a spatial autocorrelation up to 60 km among populations was detected. Base temperatures (<i>T_b</i>, minimal or base temperature permitting germination) of the 15 populations fell into a narrow range within 2.2°C with an average of 1.1°C. High final germination percentage was reached at a wide temperature range from 5 to 20°C with the highest germination percentage at 10°C. Germination rate index increased with increasing temperature from 5 to 20°C. <i>T_b</i> was positively correlated with latitude and negatively with longitude and the thermal time requirement for 50% germination was negatively correlated with latitude. The AFLP variation and germination responses were significantly associated with environmental attributes related to moisture, indicating local adaptation. However, the AFLP variation and germination was not significantly associated with the estimated population size and geographic distance to the nearest neighbor, suggesting that fragmentation has not generated considerable genetic and germination impact on the fescue populations. Marked differences in estimates of mean band frequency were observed for various groups of germinating seeds under different test temperatures. Comparisons of AFLP variation among 27 groups of seeds representing population, germination timing and test temperature indicates seed genotypes respond slightly differently to environmental variation, resulting in significant but small impact of germination timing and temperature on the genetic diversity of populations. These findings are significant not only for understanding and predicting the ecological adaptation of the species, but also for formulating effective restoration strategies for remnant populations.

Pollen contamination is a severe problem in production breeding programs since it reduces the expected gain. In an attempt to solve this problem Skogforsk created an isolation experiment in the advanced Scots pine (Pinus sylvestris) seed orchard Västerhus in Västerbotten, Sweden. This experiment involves covering blocks of trees with a tent during the pollination period so that they only can mate with each other inside. To evaluate the effects of this tent treatment one tree from inside a tent with supplementary mass pollination (SMP) and one tree from the open control were chosen for this study. 48 seeds from each tree were sampled and genotypes at 9 microsatellite (SSR) loci. The likelihood and exclusion methods for paternity assignment were used to establish the fathers to these seeds. The results showed 0% contamination inside the tent and 4-8% outside in the control. The number of fathers contributed to the fertilization of the 48 seeds was 9 inside and 15 outside. The selfing rate was unexpectedly high, 10% inside the tent and 19% outside. The mating system inside the tent need to be further evaluated to fully understand what other effect the treatment has on the future progeny.

Chickpea production in the short growing season of the Canadian Prairies is still a challenging task due to excessive and continuous vegetative growth which often results in severe yield and quality reduction. This study examined the effects of three plant growth retardants (PGR), Chlormequat Chloride (CCC), Prohexadione Calcium and Trinexapac Ethyl applied during flowering stage on vegetative growth, seed quality, yield and crop maturity of the Kabuli chickpea cultivar CDC Frontier. Field experiments were conducted at Brooks and Bow Island in southern Alberta in the 2010 and 2011 growing seasons. Four concentrations of each PGR were applied at 10, 20 and 30 days after flowering (DAF) stages. During the 2010 growing season the crop experienced above average moist and cooler temperature conditions. In contrast, later half of the 2011 growing season was above average dry and hot. None of the three PGR tested in this study had a significant effect on plant height at 30 days after treatments or on above ground biomass plant-1 at harvest. Application of PGR had no significant effects on the number of seeds m-2, except at the Brooks rain-fed site in 2011 where the PGR treatment applied at 10 and 20 DAF increased the number of seeds m-2 at harvest. An increase of 1000-seed weight of marketable seeds was obtained with Prohexadione Calcium and Trinexapac Ethyl applications at Bow Island, but the effects were not consistent across sites and years. Results suggested that the effect of PGR on 1000-seed weight of marketable seeds mainly depended upon the growing environment and the type of PGR. In general, PGR applications reduced the total and marketable seed yields. Application of Prohexadione Calcium and Trinexapac Ethyl at the Bow Island site delayed crop maturity in 2011. In contrast, the application of CCC at 6000 mg L-1 at 20 DAF accelerated crop maturity at the Brooks irrigated site in 2011. In addition to this main study, the potential effects of Pyraclostrobin and Prothioconazole fungicides on the activities of the three PGR were compared by a separate experiment conducted at the Brooks irrigated site in 2011. The results of that study revealed that there were no significant differences in the effects of PGR on chickpea vegetative growth, seed yield parameters and maturity when they were applied as a mixture with either Pyraclostrobin or Prothioconazole fungicide. In summary, results revealed that PGR applied during flowering stage were not effective on controlling vegetative growth of chickpea and did not improve seed yield and crop maturity. Their effects on yield-related traits were highly inconsistent. Thus, it can be concluded that the application of PGR is not a reliable agronomic option to handle the production issues associated with continues vegetative growth at the late reproductive stage of the chickpea cultivar CDC Frontier under the western Canadian growing conditions.

<i>Festuca hallii</i> [(Vasey) Piper] (plains rough fescue) is a dominant native grass species in the Fescue Prairie region of North America that has undergone dramatic range reduction in the past century. This research is undertaken to address the related issues associated with the effectiveness of sampling in capturing genetic diversity, the influence of habitat fragmentation on genetic variation, the geographic variation of seed germination characteristics, and the comparative genetic variation of differential germination. It was found that the tiller samples revealed slightly larger among-population variation than the seed samples. The fescue plant was genetically diverse, as revealed by the proportion of polymorphic bands, the mean band frequency, and the within-population variation. The genetic variation was not highly differentiated with only 6.5% of the total AFLP variation residing among populations. Mantel test revealed a significant correlation between genetic and geographic distances and a spatial autocorrelation up to 60 km among populations was detected. Base temperatures (<i>T_b</i>, minimal or base temperature permitting germination) of the 15 populations fell into a narrow range within 2.2°C with an average of 1.1°C. High final germination percentage was reached at a wide temperature range from 5 to 20°C with the highest germination percentage at 10°C. Germination rate index increased with increasing temperature from 5 to 20°C. <i>T_b</i> was positively correlated with latitude and negatively with longitude and the thermal time requirement for 50% germination was negatively correlated with latitude. The AFLP variation and germination responses were significantly associated with environmental attributes related to moisture, indicating local adaptation. However, the AFLP variation and germination was not significantly associated with the estimated population size and geographic distance to the nearest neighbor, suggesting that fragmentation has not generated considerable genetic and germination impact on the fescue populations. Marked differences in estimates of mean band frequency were observed for various groups of germinating seeds under different test temperatures. Comparisons of AFLP variation among 27 groups of seeds representing population, germination timing and test temperature indicates seed genotypes respond slightly differently to environmental variation, resulting in significant but small impact of germination timing and temperature on the genetic diversity of populations. These findings are significant not only for understanding and predicting the ecological adaptation of the species, but also for formulating effective restoration strategies for remnant populations.