Field studies were conducted over two years in drill- and water-seeded rice to evaluate weed control and crop response with imazethapyr programs. Barnyardgrass [Echinochloa crus-galli (L.) Beauv.] was evaluated with imazethapyr applied alone at various rates and timings. Imazethapyr controlled barnyardgrass 95 to 97% with a soil application at 87 or 70 g/ha fb 53 or 70 g/ha EPOST or LPOST. A single EPOST application of imazethapyr at 140 g/ha controlled barnyardgrass and rice yield was equal to or above those treatments receiving two applications of imazethapyr. Research was also conducted at Crowley, LA and Rayne, LA to evaluate the addition of a herbicide with broadleaf activity into imazethapyr programs applied alone early postemergence (EPOST) and in combination with imazethapyr postemergence (POST). Weeds evaluated included barnyardgrass, red rice (Oryza sativa L.), alligatorweed [Alternanthera philoxeroides (Mart.) Griseb.], and hemp sesbania [Sesbania exaltata (Raf.) Rydb. ex A.W. Hill]. Treatments consisting of imazethapyr applied at 87 g/ha alone to the soil fb a POST imazethapyr application at 53 g/ha controlled barnyardgrass above 90% late season in all studies, expect in water-seeded rice when an imazethapyr application was made at the three- to four-leaf rice stage. Red rice control with a total imazethapyr program was equivalent to, or higher, than other treatments in both drill- and water-seeded studies. Single imazethapyr applications resulted in reduced control of red rice indicating two applications of imazethapyr are required to obtain adequate control. Alligatorweed control increased with soil applications of imazethapyr. However, alligatorweed control with imazethapyr as the only herbicide in a weed control program was inconsistent and suggested only suppression. Treatments receiving a broadleaf herbicide application increased hemp sesbania control as compared with the total imazethapyr program; however, treatments with bensulfuron and triclopyr were inconsistent at controlling hemp sesbania. In drill-seeded studies, hemp sesbania was less of a problem and red rice had a greater impact on rice yield. Rice yields with total imazethapyr programs were equal to, or higher than, other treatments. However, in water-seeded studies, hemp sesbania growth was favored and yields from rice treated with broadleaf herbicides were higher than total imazethapyr programs.

This research was conducted to enhance utilization of the Liberty herbicide resistance transgene in rice. Non-lethal methods to determine the sensitivity of transgenic rice plants to hygromycin B and Liberty were developed, tested and used in this research. Four homozygous transformed plants were selected to make reciprocal crosses with their non-transformed parent cultivars Taipei 309 and Nipponbare. Their resistances to Liberty and hygromycin B were controlled by the closely linked single dominant genes bar and hpt. Some non-resistant phenotypes in the F2 populations were due to gene silencing. The bar gene in some of these plants were allelic and some were non-allelic. When seven independently transformed homozygous transgenic plants with bar and hygromycin genes from Taipei 309 and Nipponbare were crossed reciprocally, progeny evaluations showed five allelic locations among the seven transgenic plants. Twenty additional homozygous transgenic plants from independent transformation events were crossed reciprocally with the previous seven transgenic plants. Evaluation of F1, F2, and F3 populations showed that some of the genes were allelic, but most of them were non-allelic with two or more pairs of genes being expressed. The functional foreign gene (bar) appeared to be restrictively inserted into the rice genome in some cases and was not randomly inserted and expressed. Three to five repeated backcrosses were made using transgenic plants as the donor and current cultivars as the recurrent parents. The results from selected progeny rows, and two-years of yield tests with selected lines, indicated that the target bar gene could be transferred to lines similar to commercial cultivars from homozygous transformants in 4-5 years of backcrossing, giving lines similar to the recurrent parents based on phenotype and yield potential. Liberty herbicide has antibiotic characteristics and suppressed growth of several rice fungal pathogens and Burkholderia glumae in in vitro tests. Liberty had a short residual activity against Rhizoctonia solani in field tests, but single applications of Liberty after disease development had started in the field significantly reduced sheath blight ratings and yield loss. Control of sheath blight by Liberty was equal to or better than that given by the registered fungicide Quadris.

Sugarcane (inter-specific hybrids of Saccharum) is grown largely under long-term monoculture production in Louisiana. This can lead to a complex problem termed "yield decline" that results in poor root health and reduced productive capacity of sugarcane. This problem has been documented to be a limiting factor for sugarcane production in diverse regions, including Louisiana, Hawaii, Jamaica, and Australia. Previous work showed that biological factors affect root health and contribute to yield decline. The objectives of this study were to increase our understanding of microbial communities in sugarcane soils, to determine if there are differences in microbial communities associated with sugarcane roots in soil with and without a sugarcane cropping history, and to provide information on possible changes in the microbial communities resulting from monoculture that may contribute to yield decline. <p> To achieve these objectives, two approaches were used for comparing culturable organisms in soil microbial communities from soil with and without a sugarcane cropping history, and methods were adapted to reliably obtain DNA from soil microbial communities for molecular comparisons. In one approach, colonies grown on different types of culture media were quantified and characterized. In the other approach, sole carbon source utilization profiles (SCSUP) of soil communities grown in Biolog(tm) GN2 microplates were compared. Comparisons of the numbers and types of microorganisms that grew on various culture media demonstrated that differences exist between microbial communities associated with sugarcane roots in Louisiana soils with and without a recent sugarcane cropping history. The differences in community functional diversity detected by SCSUP supported the differences found in types of microorganisms isolated on selective media. The SCSUP results showed that differences in community functional diversity exist between sites in soils with a long-term sugarcane cropping history in common. <p> Methods for DNA extraction and polymerase chain reaction (PCR) amplification were optimized for sugarcane soil microbial community samples from Louisiana. This will allow molecular characterization of sugarcane rhizosphere microbial communities in the future.

“Growing Up Green,” is a research based environmental education program that teaches children about recycling, energy conservation, and composting. This program was taught to fourth grade students at H.B. Williams Elementary School, in White House, Tennessee. The children were given a pre-test before the program and a post-test two weeks after the program. The pre and post-test was composed of three parts. The three parts tested their environmental attitudes, knowledge, and behaviors. The study found that most of the children already had positive attitudes toward the environment. While, their attitudes decreased minimally after the program, they still remained very positive. The children did well on the knowledge test. Their environmental knowledge increased after the “Growing Up Green,” program. While the program did not appear to have a substantive impact on their environmental behavior adoption, the children already participated in some behaviors like recycling and conserving energy before the program, and continued these behaviors after the program, too.

The purpose of this study was to evaluate the influences of American student teachers on a rural community in New South Wales, Australia. The study analyzed interviews with twelve participants of the American student teacher program in A Rural New South Wales community, Australia. Two researchers worked together to complete this study. Both researchers were student teachers with the New South Wales community for ten weeks and taught Agriculture in one the community‟s two high schools. After allowing one year to pass, researcher one returned to the community to interview twelve individuals involved with the program. The interviewed participants were questioned based on a predetermined protocol. The interviews were then transcribed, coded, and categorized into themes by researcher two. Using participatory action research and a modified grounded theory approach, the researchers were able to identify areas of influence suggested by the participants. The participants identified nine areas of influence within the school and community of the American student teachers: cultural awareness, stereotypes, language, classroom distractions, teaching methods awareness, cultural changes in community members, student performance, community unification, and impact of student teacher presence.

Thesis (Ph. D.) in Plant Science--University of Maine, 2000. / Includes vita. Includes bibliographical references (leaves 147-160).

The inheritance of resistance to ascochyta blight in lentil (Lens culinaris Medik.) caused by Ascochyta fabae Speg. f. sp. lentis Gossen et al (Syn. A. lentis Vassil.) was studied using as parents the Canadian cultivars Eston (susceptible) and Laird (moderately resistant) and two resistant lines from ICARDA, ILL-5588 and ILL-5684. The F2, F2-derived Fa families and F2-derived F4 families of each cross were evaluated for ascochyta resistance under field conditions in an ascochyta nursery during 1987, 1988 and 1989, respectively. The parents and segregating populations were rated for ascochyta reaction on the basis of foliage symptoms, using a 1 to 9 disease rating scale, with plants rated 1 to 5 considered resistant and plants rated 7 to 9 considered susceptible. In addition percent seed-borne ascochyta infection was evaluated, using the seed plating technique. The cuItivar Eston was susceptible. Laird lentil was resistant to foliar infection by ascochyta, but its resistance breaks down in the late podding stage and under the wet conditions of the ascochyta nursery percent seed-borne ascochyta infection was even higher than in the susceptible cultivar Eston. The lines ILL-5588 and ILL-5684 were highly resistant with resistance persisting after maturity and the seed coats do not become infected and discolor materially even with prolonged exposure to wet weather at harvest. A chi-square test for goodness-of-fit of the F2 and F2- derived F3 families indicated that resistance to foliar infection by ascochyta in Laird lentil was conditioned by a single recessive gene, ral1• Results also indicated that the resistance to foliage and seed infection by ascochyta of ILL- 5588 and ILL-5684 was due to two - dominant genes,' Ral2 and Ral3. ILL-5588, but not ILL-5684, also carried the ral1 gene for resistance to foliar infection by ascochyta and is the better source of resistance to ascochyta. The high correlation between percent seed-borne ascochyta infection in Fz-derived F3 families and in F2-derived F4 families plus the medium to high heritability estimates (0.52 to 0.8l) indicate that it will be easy to select for ascochyta resistance in these crosses. An effective method of selecting for ascochyta resistance in lentil was developed. An ascochyta nursery is developed by spreading infected lentil straw between the lentil rows prior to flowering. This nursery is then sprinkled intermittently once or twice each day until about two weeks after maturity. The crop is permitted to dry naturally and selections made for ascochyta resistant F2 plants or replicated progeny rows in later generations. Ascochyta resistance is based on a low level of discolored seed (0 to 5%), reconfirmed by plating the seed to determine percent seed-borne ascochyta infection in replicated progeny rows. Only a few selections have a high level of clean bright seed and require seed planting. This technique is quick, easy, effective and efficient. Resulting selections are resistant to both foliar infection and seed infection by ascochyta.

Field and laboratory experiments were done to quantify the effects of high temperature and low soil moisture on the mortality of the immature stages of the carrot fly (Psila rosae F.). Field experiments related fly numbers to egg density and determined the period within each 8-10 week fly generation that resulted in most crop damage at harvest. Population monitoring: From 1995-1998, all stages of the carrot fly were monitored. No third fly generation was observed and no first-instar larvae were found after the end of September. Periods of high mortality were identified. [~gg mortality: Mortality was related linearly to the mean maximum soil temperature at 1 cm depth during egg development (m = 8.4t -167.3; m = % mortality, t = temperature). Under controlled conditions, eggs in dry soil died sooner at higher temperatures (>25°C) than eggs in moist soil. Fully developed eggs were more susceptible to adverse abiotic conditions than newly-laid eggs. Larval mortality: Up to 90% of first-instar larvae were killed by low soil moisture in the field. This mortality was related to the length of time larvae were exposed to dry soil conditions (m = 2.6 + 17.6d; m = % mortality, d = no. of days in dry soil). Relationship between numbers offlies and egg density: A linear relationship (e = 0.32 + 0.89[; e = log no. eggs, f = log no. flies) was identified between the numbers of carrot flies caught on sticky traps and the numbers of fly eggs recovered from carrot crops. Critical egg-laying period: Within a generation, the critical egg-laying period when most damage was caused was between 10-20 days. This coincided with the peak in fly numbers. Rearing method: A robust rearing method was developed for producing a regular supply of adults. Approximately 50% of eggs inoculated onto growing carrots gave rise to pupae.

Reviewed 06/2015; Originally published: 02/2001 / 2 pp. / To systematically monitor a young crop effectively, it is important to understand the fundamentals about counting and identifying nodes on the plant. A mainstem node is simply the point on the plant stalk where a joint with a side branch (either vegetative or fruiting branch) is formed. The basic point of reference for counting nodes on a cotton plant are the cotyledonary nodes. The cotylendonary leaves are the first two leaves to appear as the plant emerges through the soil after planting, and are actually the former halves of the seed itself. Therefore, the cotyledons form the first nodes on the mainstem of the plant and they are the only nodes which are directly opposite one another, or parallel. When counting mainstem nodes we use the cotyledon nodes as 0, then counting subsequent nodes up the mainstem toward the terminal of the plant.

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