[No abstract available] / Science, Faculty of / Botany, Department of / Graduate

An experiment involving the use of the Vetomold variety of tomato plants was conducted in a greenhouse to determine, what effect the absence of minor elements and different combinations of minor elements, would have on the growth, and chemical composition of the tomato. It was found that the presence or absence of minor elements had a significant effect on the following physical, and chemical determinations: growth rate, yield, top weight, sugar content, titratable acidity, nitrogen level, phosphorus level, potassium and calcium level of the plant tissues; iron content, total phosphorus, and potassium content of the tomatoes. It was also shown that the absence, and different combinations of minor elements, had a marked effect on the tissue structure of the leaves. / Land and Food Systems, Faculty of / Graduate

Most commercial tomato varieties require relatively high temperatures for fruit set and development, and this requirement limits tomato production in Canada. There are, however, certain newer varieties which are reported to set fruit at cool temperatures (below 55° F.). One such variety, Puck, a non-commercial type, was contrasted with the commercial varieties, Bonny Best and 498. Replicated field and greenhouse experiments were conducted to ascertain the fruit setting character of Puck, and cyto-logical and histological studies were done on some aspects of this character. The results are as follows. Puck flowered earlier and produced more blossoms than the commercial varieties and thus had a greater opportunity for fruit set at cool, temperatures. Individual Puck blossoms produced more pollen at cool temperatures than did the individual blossoms of the commercial varieties. The study on pollen formation in the different lines grown at the cool temperatures showed meiosis to be relatively normal in the pollen mother cells, and that pollen degenerated prior to anthesis. A much higher per cent of Puck pollen than Bonny Best pollen was able to germinate at cool temperatures, and fruit set at these temperatures was largely parthenocarpic. These results show that Puck has useful characteristics which contribute to fruit set at cool temperatures and which can be used in a plant breeding programme. / Land and Food Systems, Faculty of / Graduate

The development of tomato varieties is desired for commercial production in agricultural areas having relatively low spring temperatures, and/or short growing seasons. These varieties would need the character of being able to set fruit under the unfavorable conditions of temperatures below 65 F. the English variety. Puck, has the characteristic of setting fruit at low temperatures, but is otherwise unsuitable for profitable tomato production. To identify the mechanism of this desirable character in Puck, and mode of inheritance of the character, experiments were carried out to study flower production, pollen compatibility relationships, and the production, development and germination of pollen. Experiments were carried out at two temperature levels in greenhouses to observe effects on flower and fruit development. These plant responses were studied in a relatively cool greenhouse kept at 55°- 65° F. and in another house kept at 65 - 75°P. range which is considered optimum for tomato production. The plants used were Puck and Bonny Best varieties and their reciprocal F1 hybrids. Blower production was significantly increased by lower temperatures, and the increases on Puck and the hybrids were larger than on Bonny Best. Fruit setting was reduced by low temperatures, suggesting reduction of self-compatibility in the hybrids as well as in Bonny Best, the latter having a high percentage of parthenocarpic fruits. The number of days between pollination and maturity of fruits was found to be in versely related to the number of seed formed in the fruits. Low temperatures, probably interacting with low light intensities and short photoperiods, appeared to reduce markedly the viability of pollen on all lines, as shown by viability tests on the pollen with the acetocarmine staining procedure and with germination tests in vitro. These experiments revealed an unexpected variability in pollen germination, which was possibly due to the effects of temperature on microsporogenesis. Percentages of normal meioses were only slightly affected, but there was evidence that a minimum temperature is required for the completion of meiosis, and that such minima were different for different meiotic stages. Rates of pollen deterioration following dehiscence of the anthers were found to be different in different varieties. Puck had a higher number of flowers produced at low temperatures showed no reduction of self-compatibility, and had a consistent seed set; therefore, this variety is to be considered a possible source of germ plasm in the breeding of tomatoes tolerant of cool temperatures. / Land and Food Systems, Faculty of / Graduate

Tomato fruits which are misshapen or rough are frequently a problem in the field crop, and sometimes in the greenhouse crop. This horticultural problem has been attributed to the exposure of seedling plants to relatively cool temperatures (below 15°C), but lack of knowledge about conditions causing rough fruit resulted in experiments to explore the influence of genotype and relatively cool temperatures on the production of rough fruit. A field study was carried out at the University of British Columbia in 1975 using 3 cultivars (Bonny Best, Fireball and Immur Prior Beta [IPB]) and 2 reciprocal hybrids of Bonny Best and IPB. In that season, there was a substantial quantity of rough fruit, and there were highly significant differences among genotypes. Controlled environment studies were used in 3 greenhouse experiments. In the first, tomato seedlings of 6 cultivars (Bonny Best, Cold Set, Early Red Chief, Fireball, IPB and Vendor) were chilled for either 3 or 7 nights to 10° ± 1°C at each of 4 different ages ranging from 3.5 to 6.5 weeks after seeding. Control plants were kept at 19° ± 1°C. None of the cultivars in any treatment produced enough rough fruit to be of any horticultural concern, but there were some highly significant differences (1% level) among the cultivars for the number of rough fruits produced. The second experiment employed more severe chilling conditions. Seedlings from 4 age groups ranging from 3 to 6 weeks were chilled for 2 weeks using a night temperature low of 4.4°C and a day high of 12.8°C. Four cultivars (Cold Set, Fireball, IPB and Vendor) were used, and although there were significant differences (5% level), the numbers of rough fruit did not match the horticultural problem. The third controlled environment experiment employed a regime of hourly changes in temperature to range from a night low of 4.4 °C and a day high of 21.1 °C, using only 2 cultivars (IPB and Vendor). Control plants were kept at 20.0UC/23.9°C. The plants were transferred to controlled environment chambers 35 days after seeding, and kept in the contrasting temperature regimes until fruit matured. Although the IPB had a significantly greater number of rough fruit than Vendor, the magnitude of the numbers of rough fruit were too small to be of practical importance. Apparently, the rough fruit problem is not caused by the simple matter of exposure to chilling temperatures, and it is supposed that an interaction, possibly a very complex one, may be the cause of this type of misshapen fruit. / Land and Food Systems, Faculty of / Graduate

Genevieve Crawford / Typescript / M.S. Florida State College for Women 1914 / Includes bibliographical references

No description available.

Thesis (Ph. D.)--University of Adelaide, Dept. of Botany, 1960. / Typewritten. Includes bibliographical references (leaves 209-222).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1976. / Vita. Abstract. Includes bibliographical references (leaves 42-47). Also available via the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on May 11, 2009) Thesis advisor: David H. Trinklein. Includes bibliographical references.