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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

Interactions between a gall making fly, Dasineura oxycoccana (Diptera: Cecidomyiidae), and its host plant, cultivated cranberry (Vaccinium macrocarpon)

Tewari, Sunil 01 January 2013 (has links)
Cranberry tipworm, Dasineura oxycoccana Johnson (a gall-making fly), disrupts normal growth of cranberry (Vaccinium macrocarpon Aiton) by injuring the apical meristem of shoots or uprights. The impact of larval feeding injury on reproductive parameters of cranberry was determined, from one growing season to next, at upright (Maine and Massachusetts, 2008–2009) and plot levels (Massachusetts, 2009–2010 and 2010–2011). I also estimated the proportions of uprights injured because of tipworm feeding at several cranberry production sites (Massachusetts and Maine) and the proportions of uprights that produced flowers and fruits in the next growing season. Tipworm-injured uprights tagged at the end of the growing season did not produce floral-units (following year) across sites in both Massachusetts and Maine. There was significant variation among the sampled sites in the proportions of tipworm-injured uprights and also in the proportions of uprights with flowers in the next growing season (Massachusetts and Maine). A trend was apparent wherein sites with higher tipworm injury levels had relatively lower flowering proportions in the next growing season. However, sites in Massachusetts did not differ in the proportions of uprights that set fruit and in a replicated study, significant reduction in tipworm injury at plot level (using insecticide) did not impact flower and fruit production in the next growing season. A two-year field study was carried out at three different locations to determine the impact of tipworm feeding injury on the reproductive and vegetative growth of two cranberry cultivars ('Howes' and 'Stevens') in Massachusetts. Individual uprights of cranberry exhibited tolerance to natural (tipworm) and simulated apical meristem injury in the current growing season (fruit production) and results were corroborated by a greenhouse study. In the field study, weight of fruit was higher in tipworm-injured uprights as compared with intact control uprights at the sites with Howes. However, majority of injured uprights (tipworm and simulated) did not produce new growth from lateral buds (side-shoots) before the onset of dormancy. In the next growing season, fewer injured uprights resumed growth and produced flowers as compared with intact uprights at two of the three sites.
212

Gene Modification of Rubber Producing Dandelions

Liu, Mingde January 2019 (has links)
No description available.
213

Influence of Cultural Practices on Triploid Watermelon Yield and Quality

Lamaster, Kaitlyn 01 May 2020 (has links)
Triploid watermelon (Citrullus linatus) has gained a significant market share within the United States over the last two decades, and since they require specialized cultural practices compared to seeded types, understanding the influences of these cultural practices on fruit yield and quality is important to maximize production to meet consumer demand. A study was conducted in 2018 and 2019 at the Southern Illinois University Research Center in Carbondale (SIUC HRC) to determine the effect of different cultural practices (e.g., cultivar, pollinizer ratio, water, and nitrogen inputs) on triploid watermelon fruit yield and quality characteristics. Seeded pollinizer ‘Ace Plus’ was inter-planted at 14% and 28.5% pollinizer ratios in two triploid cultivars, Charismatic and Captivation. Neither high nor low water or nitrogen levels evaluated influenced triploid watermelon yields or quality characteristics. Triploid watermelon cultivar influenced fruit size and quality. Both fruit length (P ≤ 0.001) and fruit width (P =0.0055) were influenced by the cultivar used. However, there were no differences for total fruit weight (kg) between the cultivars used. For internal fruit quality, the cultivar used also influenced hollow heart incidence (P = 0.0042). The high cost of triploid watermelon seed and transplants also provide a need to better understand the ratios required to maximize revenue. A field study was conducted in 2018 and 2019 at the SIUC HRC. The objective was to evaluate the influence of different pollinizer ratios on fruit quality, yield, and revenue. ‘Belmont’ triploid watermelon was inter-planted with the diploid pollinizer ‘Ace Plus’ at different diploid to triploid ratios (10%, 20%, 30%, or 40% pollinizer). Our results indicated a linear plateau model between pollinizer ratio and watermelon fruit yield, optimizing at 30% diploid plants in the field. Thus, this study indicated that the highest triploid watermelon yields and revenue were obtained at 30% diploid pollinizer frequency. The identification of an optimum pollinizer ratio for triploid watermelon production can increase grower profits. Low pollinizer ratios can result in low yield and revenue in contrast to higher pollinizer ratios that could result in increased yield production along with decreased input costs. Our results indicated that high fruit number and increased revenue was obtained at an optimal 30% diploid pollinizer inter-planting ratio. This indicates that standard ratios used that are below 30% may not be as economical.
214

Soil Moisture Responses in Traditional and Drought Adapted Landscapes in the Intermountain West

Gregory, James 01 December 2008 (has links)
Water conservation in the Intermountain West will be an important issue in the future as population and demand for limited water resources increases. In Utah, outdoor water use accounts for up to 60% of total per capita water use with 67% of that outdoor water being used to irrigate non native plant species to maintain a uniform green appearance. The objective of this study was to measure intra landscape changes in soil water potential during a 21.5 day dry down from DOY 215 to 236.5 in the summer of 2005 and 2006. Four, 2 x 2 replicated traditional and drought tolerant landscapes were instrumented with inexpensive resistance blocks at four points and three depths (15, 45, and 90 cm) at the Utah Botanical Center, Kaysville, Utah. Each mixed vegetation landscape consisted of a drainage lysimeter planted with annual and perennial shrubs, bunch grasses, turf grasses, and a 1.5 m coniferous tree. Mean soil water potential varied significantly between landscape treatments (p 0.05).and was most negative at 15 cm at the end of the dry down under Kentucky bluegrass (Poa pratensis. L) (-428 ± 50 kPa). In contrast, Buffalograss (Buchloe dactyloides) was significantly more negative at 45 cm and 90 cm (-291 ± 50 kPa and -197 ± 50 kPa), respectively, compared to Kentucky bluegrass, suggesting greater soil water extraction by deeper roots. Mean soil water potentials were less negative under the shrub and conifer treatments compared to turfgrasses at the end of the dry down on DOY 236.5, suggesting lower plant water use and/or hydraulic redistribution.
215

The Basis of Browsing Tolerance in Shrubs of the Intermountain West: Growth Rates and Meristematic Potential

Wandera, Jackson L 01 May 1990 (has links)
Relative growth rates (RGRs) and meristematic potential of big sagebrush (Artemisia tridentata, in some experiments ssp. tridentata Nutt. and in other experiments ssp. vaseyana [Rydb] Beetls), bitterbrush (Purshia tridentata [Pursh] DC), serviceberry (Amelanchier alnifolia Nutt.), birchleaf mountain mahogany (Cercocarpus montanus Raf.), curlleaf mountain mahogany (C. ledifolius Nutt.) and big tooth maple (Acer grandidentatum Nutt.) were quantified under both glasshouse and field conditions. The relationships between the RGRs, meristematic potential and regrowth capacity of the shrub species were then determined. Sagebrush exhibited a significantly higher RGR than the other species at both high and low nutrient levels under glasshouse conditions. Four of the other shrub species had similar RGRs. The shrub species also exhibited different patterns of biomass and nutrient allocation. Sagebrush allocated most of its resources to leaf production, and in contrast, the other species tended to allocate similar amounts of resources to both leaf and root production. In the glasshouse experiment, neither RGRs nor patterns of biomass and nutrient allocation were related to growth form. Under field conditions, curlleaf and birchleaf mountain mahogany exhibited similar RGRs while both serviceberry and maple had similar but significantly lower growth rates. Except for sagebrush, which died following simulated browsing, four other shrub species exactly compensated for lost tissues. The mean RGRs of those shrub species were correlated significantly with compensatory growth capacity. Loss of 90% of buds on previous year's growth did not cause a meristematic constraint to regrowth production. Instead, it stimulated regrowth production. The shrub species we evaluated also exhibited differences in meristematic potential. Curlleaf and birchleaf mountain mahogany had a greater number of buds and long shoots per plant but a lower percentage of long shoots at the basal position on twigs. In contrast, serviceberry and maple had fewer buds and long shoots per plant but a higher percentage of long shoots at the basal position on twigs. The meristematic potential of the shrub species correlated with regrowth capacity.
216

Tea As An Alternative Crop for Mississippi

LeCompte, Judson Stuart 10 August 2018 (has links)
Farmers in Mississippi have begun planting tea (Camellia sinensis) to diversify their crops. Camellia sinensis is an evergreen shrub whose leaves are used to make commonly consumed tea beverages. Tea has the potential to benefit the agricultural industry in Mississippi. While tea has been grown in other countries for centuries, there is little research-based information to guide farmers on growing tea in the United States. For domestic production to become effective, growers need to identify areas to save money to compete with countries with lower input costs. This study showed growers can fertilize at 2 g nitrogen (N) per container, reducing input costs, and produce comparable plants to those receiving higher N rates used in this study. While lowering the amount of N applied to plants in containers is an economical benefit to producers, there is also an environmental benefit to applying less N.This research also examined whether the use of colored shade cloth would increase plant growth and survival rate of newly planted tea. This study indicated in year 1, plants grown under shade treatments had 100% survival rate compared to plants grown without shade which had a survival rate of 46.67%. Shade cloth may be useful for tea producers in Mississippi when irrigation is limited. For tea producers with irrigated fields, the added expense of shade cloth may not be justified. Finally, planting date was evaluated to determine effects on plant growth and survival rate. In all planting dates except 3 April 2017, survival rate was over 70%, suggesting producers can plant tea in late fall and winter in Mississippi. While only in its infancy, the US tea industry has the potential to reduce the amount of imported tea, providing a boost to local economies and potentially reducing the environmental impact from shipping.
217

Acceleration of juvenility in Malus seedlings.

Lee, Frances W. L. January 1965 (has links)
No description available.
218

Off-flavour development in frozen cauliflower.

Smith, Richard B. January 1966 (has links)
No description available.
219

The Effect of Nitrogen Fertilization on the Growth and Fruit Production of Halehaven Peach Trees and on the Chemical Composition of the Leaves

Chhonkar, Vijendra Pal Singh January 1949 (has links)
No description available.
220

Improvement of Rubber Yield Related Characteristics using Different Breeding Methods

Luo, Zinan January 2017 (has links)
No description available.

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