Orientador: Roberval Daiton Vieira / Banca: Nelson Moreira de Carvalho / Banca: Marco Eustáquio de Sá / Resumo: Na implantação de uma cultura, a utilização de sementes com elevado potencial fisiológico é fundamental para o estabelecimento da mesma, pois representa um dos principais fatores que proporcionará à espécie a possibilidade de expressar seu máximo potencial produtivo. O uso de testes de vigor adequados torna-se imprescindível na avaliação do potencial fisiológico dos lotes produzidos e comercializados por uma empresa. Assim, o trabalho teve por objetivo estudar os testes de envelhecimento acelerado e de deterioração controlada como métodos para avaliar o vigor de sementes de beterraba (Beta vulgaris L.), correlacionando seus resultados com os do teste de emergência de plântulas em campo. Foram utilizados sete lotes de sementes hermeticamente embaladas da cultivar "Top Tall Early Wonder", adquiridos no comércio e previamente lavados em água corrente. O vigor de sementes de beterraba pode, portanto, ser avaliado eficientemente por intermédio dos testes de envelhecimento acelerado tradicional, envelhecimento acelerado em solução salina saturada e deterioração controlada. / Abstract: The use of seeds with high physiological potential is fundamental for the establishment of the crop, because it represents one of the major factors that will provide to the crop the possibility of expressing your maximum productive potential. The use of appropriate vigor tests becomes indispensable to evaluate the physiological potential of the produced and marketed seed lots. Therefore, this work was carried out in order to study the accelerated aging and deterioration controlled tests as methods to evaluate the vigor of beet seeds (Beta vulgaris L.), correlating their results with seedlings field emergency. The vigor of beet seeds can, therefore, be evaluated efficiently using accelerated aging, both traditional and in saturated salt solution and controlled deterioration tests. / Mestre

Made available in DSpace on 2014-06-11T19:28:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-02-05Bitstream added on 2014-06-13T19:16:23Z : No. of bitstreams: 1 silva_jb_me_jabo.pdf: 136814 bytes, checksum: b921e2dc9bc5d532a4908f6513e227ac (MD5) / Na implantação de uma cultura, a utilização de sementes com elevado potencial fisiológico é fundamental para o estabelecimento da mesma, pois representa um dos principais fatores que proporcionará à espécie a possibilidade de expressar seu máximo potencial produtivo. O uso de testes de vigor adequados torna-se imprescindível na avaliação do potencial fisiológico dos lotes produzidos e comercializados por uma empresa. Assim, o trabalho teve por objetivo estudar os testes de envelhecimento acelerado e de deterioração controlada como métodos para avaliar o vigor de sementes de beterraba (Beta vulgaris L.), correlacionando seus resultados com os do teste de emergência de plântulas em campo. Foram utilizados sete lotes de sementes hermeticamente embaladas da cultivar Top Tall Early Wonder, adquiridos no comércio e previamente lavados em água corrente. O vigor de sementes de beterraba pode, portanto, ser avaliado eficientemente por intermédio dos testes de envelhecimento acelerado tradicional, envelhecimento acelerado em solução salina saturada e deterioração controlada. / The use of seeds with high physiological potential is fundamental for the establishment of the crop, because it represents one of the major factors that will provide to the crop the possibility of expressing your maximum productive potential. The use of appropriate vigor tests becomes indispensable to evaluate the physiological potential of the produced and marketed seed lots. Therefore, this work was carried out in order to study the accelerated aging and deterioration controlled tests as methods to evaluate the vigor of beet seeds (Beta vulgaris L.), correlating their results with seedlings field emergency. The vigor of beet seeds can, therefore, be evaluated efficiently using accelerated aging, both traditional and in saturated salt solution and controlled deterioration tests.

In total, 801 samples of potato leafroll disease were collected and tested for potato leafroll virus (PLRV) and beet western yellows virus (BWYV) in 1986, 1987, and 1988 using triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA) and virus-specific monoclonal antibodies. The samples represented 32 cultivars and originated in eight Canadian provinces and 12 American states. None of the samples tested positive for BWYV, whereas 772 (96.4%) tested positive for PLRV. Neither PLRV nor BWYV could be recovered, with aphid transfers to indicator hosts, from 28 of the 29 samples that tested negative for both viruses. PLRV was recovered from one sample that originally tested negative by TAS-ELISA; the indicator plant tested positive for PLRV by TAS-ELISA. Nucleic acid spot hybridization (NASH) using random primed and cloned cDNA probes was compared with double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and TAS-ELISA, and aphid transmission tests for detection and identification of PLRV and BWYV in 165 potato leafroll disease samples. All of the samples tested negative for BWYV with each of the assay procedures. PLRV was detected in all of the samples with TAS-ELISA, NASH with a cloned cDNA probe for PLRV, and with aphid transmission to ground cherry (Physalis pubescens). Both DAS-ELISA and NASH using random primed cDNA produced one false-negative result. Shepherd's purse (Capsella bursa-pastoris) was a host for 72% (119/165) of the PLRV isolates. The susceptibility of potato to BWYV was tested by inoculating Russet Burbank with three isolates of BWYV from Canada and four from the United States. Two of the isolates were in a mixed infection with PLRV. None of the isolates were transmitted by Myzus persicae to virus-free potato plants, either by themselves or in association with PLRV. Common weeds were surveyed in the potato-producing areas of British Columbia for PLRV and BWYV. In total, 10,098 weed samples, representing 98 species in 22 plant families, were collected and tested by TAS-ELISA from 1986 to 1989. BWYV was detected in 1% of the samples; the hosts were: chickweed, common groundsel, heart-podded hoary cress, hedge mustard, little western bittercress, prickly lettuce, shepherd's purse, and wild radish. PLRV was detected in three volunteer potato plants, two samples of shepherd's purse, and one black nightshade plant. The low incidence of PLRV in plants other than potato indicates that weeds are of minor importance in the epidemiology of potato leafroll disease in British Columbia. / Land and Food Systems, Faculty of / Graduate

Cercospora leaf spot is an economically devastating disease of sugar beet caused by the fungus Cercospora beticola. It has been demonstrated recently that the C. beticola CTB cluster is larger than previously recognized and includes novel genes involved in cercosporin biosynthesis and a partial duplication of the CTB cluster. Several genes in the C. nicotianae CTB cluster are known to be regulated by ‘feedback’ transcriptional inhibition. Expression analysis was conducted in wild type (WT) and CTB mutant backgrounds to determine if feedback inhibition occurs in C. beticola. My research showed that the transcription factor CTB8 which regulates the CTB cluster expression in C. nicotianae also regulates gene expression in the C. beticola CTB cluster. Expression analysis has shown that feedback inhibition occurs within some of the expanded CTB cluster genes. The partial duplication of the CTB cluster was not found to be light activated or subject to feedback inhibition. / USDA Bolton Sugar Beet Pathology Lab

Rhizoctonia solani causes damping-off, and root and crown rot of sugar beet (Beta vulgaris L.) and overwinters as sclerotia and mycelia. Research was conducted to determine how best to produce large quantities of sclerotia and mycelia in vitro, and compare their pathogenicity with traditionally used colonized barley grains to sugar beet in vitro and in vivo. The greatest number of sclerotia was produced on amended clarified V8 medium and sclerotia caused more disease compared to barley inoculum in the greenhouse. The bio-control potential of Penicillium pinophilum on R. solani AG2-2 on sugar beet was evaluated in vitro and in vivo. Results showed that the presence of P.pinophilum with R.solani reduced damping-off by 75% and thus have the potential to be developed as a bio-control agent for this pathogen.

Due to considerable loss through root-rot of mother beets while in storage during the winter of 1918-1919 the Amalgamated Sugar Company asked advice in regard to planting beets which had decay lesions on them. Would the beets yield seed if planted? How much seed would these beets yield as compared with healthy beets? Would the seed produced be injured by having been grown on decayed beets? It was felt that an experiment carried out with the above questions in view would bring out many facts upon which to base conclusions in answering the questions of the Sugar Company.

Various ammonium salts, urea, aqua ammonia, and anhydrous ammonia are important sources of nitrogen for the fertilization of agricultural crops. While ammonia and its compounds are useful as fertilizers, they can be, and often are, toxic to many plants (Willis and Rankin, 1930; Stout and Tolman, 1941; Raleigh, 1942; Stoll, 1954; Lorenz, 1955; Grogan and Zink, 1956; Allen, 1962; Cooke, 1962; Allred, 1963; Court et al, 1964; Hood and Ensminger, 1964). There are also products which have been designed to retard the oxidation of ammonia and its compounds (Go ring, 1962). It is therefore important that the effects of ammonia and its compounds on plants, plant growth and plant metabolism be fully understood.

Many factors that influence the growth and quality of sugar beets behave in one way under one set of conditions and in quite another under other conditions. Consequently, these factors should be considered together under a dynamic situation to find their interrelations and their influence on sugar beet yield. This study is a statistical analysis of the interaction of fertilizer and soil moisture potential with the yield of sugar beets grown in a crop rotation under different regimes of irrigation conducted over a period of seven years. The data are available for the years 1949 through 1956, from an intensive field experiment conducted under Western Regional Research Project W-29, entitled Soil-Water-Plant Relations under Irrigation. There is need of a complete statistical analysis of third order interaction for the whole cultural rotation. This third order interaction has been examined for the sugar beet crop grown in the seven years of the general cultural rotation, which includes peas, first year alfalfa, second year alfalfa, potatoes, and sugar beets.

Insecticides in the diamide class have a novel mode of action and have become a key component for management of agriculturally important lepidopteran pests since their introduction in 2008. Corn earworm, Helicoverpa zea (Boddie); and the armyworm complex including fall armyworm, Spodoptera frugiperda (J.E. Smith); and Spodoptera exigua (Hübner); are significant pests of agroecosystems in the Mid-southern and Southeastern regions of the United States. They have developed resistance to, and/or inconsistent control has occurred with most chemical classes. The objectives of this study were to establish susceptibility levels of field populations of H. zea, S. frugiperda, and S. exigua collected in the Mid-southern and Southeastern regions of the United States to flubendiamide and chlorantraniliprole. To achieve equivalent levels of mortality for each species, a higher concentration of flubendiamide was required compared to chlorantraniliprole. Furthermore, two experiments were conducted to determine the systemic and residual efficacy of chlorantraniliprole and flubendiamide against H. zea on vegetative and reproductive structures of soybean. Chlorantraniliprole moved systemically and had significantly greater control than flubendiamide in the systemic and residual study out to 31 DAT. Flubendiamide did not move systemically but provided significant residual control out to 31 DAT compared with the untreated control. Neither insecticide was detected in reproductive structures. Finally, to determine the risk of resistance development, a S. exigua colony, originating from a field collection in 2013, was separated into three cohorts that were independently selected with three concentrations (0.016, 0.020, and 0.025 ppm) of flubendiamide incorporated into a meridic diet. These concentrations were chosen from the LC30, LC60 and LC90 of the original colony. Resistance ratios never increased past 2.11old. The highest resistance ratios occurred after 18 generations for the LC30 colony, 19 generations for the LC60 colony, and 13 and 15 generations for the LC90 colony. After reaching their highest point of resistance, the colonies began to decline in egg production and larval survivability and did not recover. After 22 generations the selected colonies were terminated. The results from this portion of the study suggest that the potential for resistance development of beet armyworm to flubendiamide is unclear.

No description available.