TITLE: Canola Production as Influenced by Previous Crop and Tillage System MAJOR PROFESSORS: Dr. Michael Schmidt and Dr. Brian Klubek This study was conducted to compare the profitability of winter canola versus winter wheat following corn and soybean under a reduced till and no till regime. Yield of double crop soybean production behind canola vs. wheat was also studied. The experiment was designed as a complete factorial with a split-split-split plot arrangement using 4 replications. Corn/soybean served as the main effect. Tillage was the sub-plot, and winter canola/wheat served as the sub-sub-plot. Two varieties each of canola and wheat were tested as sub-sub-sub plot. Fall stand, seed yield, and double crop soybean yield were measured for all plots. Interactions between either pair of canola or wheat varieties with previous crop or tillage system were not detected either season. Canola produced a higher yield after a previous crop of corn than after a previous crop of soybean in 2005-2006. In 2007-2008, the yield of canola after soybean was higher however this difference was not significant. No influence of previous crop on wheat yield was detected either season. The influence of tillage on canola and wheat yield was inconsistent across seasons. Canola produced a higher yield under reduced till in 2007-2008, but not in 2005-2006. In 2005-2006, wheat produced a higher yield under no-till and a higher yield under reduced till in 2007-2008. In 2007-2008, a significant interaction between previous crop and tillage system was detected for both canola and wheat. Canola yield was significantly reduced by no-till after corn but not so by no-till after soybean. Wheat yield was significantly lower following corn no-till than following soybean no-till, however, there was no difference in wheat yield following corn or soybean under reduced till. The yield of double crop soybean did not differ following winter canola or winter wheat either season, however in 2005-2006, yield was higher following corn after either canola or wheat. The double crop soybean yield was 1,421 hg/ha in 2005-2006 and was 3,161 kg/ha in 2007-2008. The results herein indicate that canola and wheat can be profitably grown behind either corn or soybean and under either a reduced till or a no-till system. However, these results are inconclusive as to which combination of previous crop or tillage system should be recommended for either winter crop. It does appear that there is a greater concern establishing a canola stand under a no-till system. Canola provided greater gross revenue over that of wheat both seasons, even after considering the additional canola seed and nitrogen costs. When combined across seasons, canola had a mean yield of 3,838 kg/ha and a mean revenue of $1,236/ha. Wheat had a mean yield of 5,511kg/ha and a mean revenue of $939/ha. The seed and nitrogen cost differential was computed at $70. Thus, the canola crop provided revenue that was 25% higher per hectare than the wheat crop.

Rizobactérias promotoras de crescimento vegetal (PGPR) podem estimular o crescimento da planta hospedeira através da produção de determinadas substâncias, supressão de organismos deletérios, disponibilidade e captura de nutrientes minerais, entre outras atividades. Essas bactérias têm sido objeto de estudos devido aos efeitos produzidos em importantes culturas comerciais. A canola é uma opção de planta para cobertura de solo, para rotação de culturas e para produção de óleo, tanto comestível quanto biodiesel. No entanto, estudos sobre a diversidade de micro-organismos associados com culturas de canola e seu potencial para promover o crescimento das plantas são escassos. Dois estudos foram conduzidos nesse trabalho com os seguintes objetivos: i) isolar e identificar bactérias cultiváveis associadas ao solo rizosférico e raízes de canola (Brassica napus) para verificar se possíveis mudanças nas comunidades microbianas estão associadas com os diferentes estágios de rotação de culturas e com as diferentes fases do crescimento da planta; ii) avaliar as habilidades de promoção de crescimento vegetal dos isolados bacterianos; iii) utilizar isolados selecionados em experimentos in vivo em casa de vegetação; iv) desenvolver um microarranjo para identificação de bactérias diazotróficas cultiváveis e conhecidas de diferentes ambientes. Os resultados obtidos pelo isolamento tradicional indicaram a presença de diferentes populações de PGPRs no solo rizosférico e no interior das raízes de canola nos diferentes estágios de rotação de cultura. Além disso, a estrutura da comunidade microbiana foi influenciada pela variação sazonal, como indicado pelos diferentes gêneros identificados nos diferentes estágios de desenvolvimento da planta, havendo, também, uma correlação positiva entre a diversidade bacteriana e a quantidade de precipitação mensal. Agrobacterium, Burkholderia, Enterobacter e Pseudomonas foram os gêneros bacterianos predominantes entre todos os identificados. Muitas das bactérias isoladas foram capazes de produzir compostos indólicos e sideróforos, solubilizar fosfato e algumas também foram capazes de fixar nitrogênio. Alguns dos isolados promoveram o crescimento da planta em casa de vegetação. Com relação ao microarranjo para identificação de bactérias diazotróficas cultiváveis e conhecidas de diferentes ambientes, apesar de terem sido realizados apenas testes preliminares, acredita-se que o microarranjo apresente um bom potencial para atingir o seu objetivo. Esse facilitará a busca por bactérias com propriedades de promoção de crescimento vegetal para a produção de um inoculante para as culturas de canola do sul do Brasil. / Plant growth promoting rhizobacteria (PGPR) can stimulate host plant growth through the production of plant-growth substances, suppression of deleterious organisms, availability and uptake of mineral nutrients and other activities. These bacteria have been the object of studies due to the effects produced in commercially important crops. Canola is an option for ground cover plant for crop rotation and the production of oil both as food and biodiesel. However, studies on the diversity of such microorganisms associated with canola crops and their potential to promote plant growth are scarce. Two studies were conducted in this work with the following objectives: i) isolate and identify culturable bacteria associated with rhizospheric soil and roots of canola (Brassica napus) to verify if possible changes in microbial communities were associated with different stages of crop rotation and the different stages of canola growth; ii) evaluate the PGP abilities of bacterial isolates iii) test some of the isolates for in vivo experiments in a greenhouse, iv) develop a microarray for identification of culturable diazotrophs in different environments. The results obtained by traditional isolation indicated the presence of a diverse population of PGPR in the rhizospheric soil and inside the roots of canola at different stages of crop rotation. Moreover, the microbial community structure was influenced by seasonal variation, as indicated by the different genera identified at different stages of canola development. There was also a relationship between bacterial diversity and monthly rainfall. Agrobacterium, Burkholderia, Enterobacter, and Pseudomonas were the prominent bacterial genera among all identified. Several of the isolated bacteria could produce indolic compounds and siderophores, to solubilize phosphate and some could also fix nitrogen. Some of the isolates were able to promote plant growth. Regarding the microarray, although only preliminary tests were performed, it was possible to show that the microarray has a good potential to achieve its goal. It will make easy the search for bacteria with properties of plant growth promotion for the production of an inoculant for canola cultivated in southern Brazil.

Rizobactérias promotoras de crescimento vegetal (PGPR) podem estimular o crescimento da planta hospedeira através da produção de determinadas substâncias, supressão de organismos deletérios, disponibilidade e captura de nutrientes minerais, entre outras atividades. Essas bactérias têm sido objeto de estudos devido aos efeitos produzidos em importantes culturas comerciais. A canola é uma opção de planta para cobertura de solo, para rotação de culturas e para produção de óleo, tanto comestível quanto biodiesel. No entanto, estudos sobre a diversidade de micro-organismos associados com culturas de canola e seu potencial para promover o crescimento das plantas são escassos. Dois estudos foram conduzidos nesse trabalho com os seguintes objetivos: i) isolar e identificar bactérias cultiváveis associadas ao solo rizosférico e raízes de canola (Brassica napus) para verificar se possíveis mudanças nas comunidades microbianas estão associadas com os diferentes estágios de rotação de culturas e com as diferentes fases do crescimento da planta; ii) avaliar as habilidades de promoção de crescimento vegetal dos isolados bacterianos; iii) utilizar isolados selecionados em experimentos in vivo em casa de vegetação; iv) desenvolver um microarranjo para identificação de bactérias diazotróficas cultiváveis e conhecidas de diferentes ambientes. Os resultados obtidos pelo isolamento tradicional indicaram a presença de diferentes populações de PGPRs no solo rizosférico e no interior das raízes de canola nos diferentes estágios de rotação de cultura. Além disso, a estrutura da comunidade microbiana foi influenciada pela variação sazonal, como indicado pelos diferentes gêneros identificados nos diferentes estágios de desenvolvimento da planta, havendo, também, uma correlação positiva entre a diversidade bacteriana e a quantidade de precipitação mensal. Agrobacterium, Burkholderia, Enterobacter e Pseudomonas foram os gêneros bacterianos predominantes entre todos os identificados. Muitas das bactérias isoladas foram capazes de produzir compostos indólicos e sideróforos, solubilizar fosfato e algumas também foram capazes de fixar nitrogênio. Alguns dos isolados promoveram o crescimento da planta em casa de vegetação. Com relação ao microarranjo para identificação de bactérias diazotróficas cultiváveis e conhecidas de diferentes ambientes, apesar de terem sido realizados apenas testes preliminares, acredita-se que o microarranjo apresente um bom potencial para atingir o seu objetivo. Esse facilitará a busca por bactérias com propriedades de promoção de crescimento vegetal para a produção de um inoculante para as culturas de canola do sul do Brasil. / Plant growth promoting rhizobacteria (PGPR) can stimulate host plant growth through the production of plant-growth substances, suppression of deleterious organisms, availability and uptake of mineral nutrients and other activities. These bacteria have been the object of studies due to the effects produced in commercially important crops. Canola is an option for ground cover plant for crop rotation and the production of oil both as food and biodiesel. However, studies on the diversity of such microorganisms associated with canola crops and their potential to promote plant growth are scarce. Two studies were conducted in this work with the following objectives: i) isolate and identify culturable bacteria associated with rhizospheric soil and roots of canola (Brassica napus) to verify if possible changes in microbial communities were associated with different stages of crop rotation and the different stages of canola growth; ii) evaluate the PGP abilities of bacterial isolates iii) test some of the isolates for in vivo experiments in a greenhouse, iv) develop a microarray for identification of culturable diazotrophs in different environments. The results obtained by traditional isolation indicated the presence of a diverse population of PGPR in the rhizospheric soil and inside the roots of canola at different stages of crop rotation. Moreover, the microbial community structure was influenced by seasonal variation, as indicated by the different genera identified at different stages of canola development. There was also a relationship between bacterial diversity and monthly rainfall. Agrobacterium, Burkholderia, Enterobacter, and Pseudomonas were the prominent bacterial genera among all identified. Several of the isolated bacteria could produce indolic compounds and siderophores, to solubilize phosphate and some could also fix nitrogen. Some of the isolates were able to promote plant growth. Regarding the microarray, although only preliminary tests were performed, it was possible to show that the microarray has a good potential to achieve its goal. It will make easy the search for bacteria with properties of plant growth promotion for the production of an inoculant for canola cultivated in southern Brazil.

Rizobactérias promotoras de crescimento vegetal (PGPR) podem estimular o crescimento da planta hospedeira através da produção de determinadas substâncias, supressão de organismos deletérios, disponibilidade e captura de nutrientes minerais, entre outras atividades. Essas bactérias têm sido objeto de estudos devido aos efeitos produzidos em importantes culturas comerciais. A canola é uma opção de planta para cobertura de solo, para rotação de culturas e para produção de óleo, tanto comestível quanto biodiesel. No entanto, estudos sobre a diversidade de micro-organismos associados com culturas de canola e seu potencial para promover o crescimento das plantas são escassos. Dois estudos foram conduzidos nesse trabalho com os seguintes objetivos: i) isolar e identificar bactérias cultiváveis associadas ao solo rizosférico e raízes de canola (Brassica napus) para verificar se possíveis mudanças nas comunidades microbianas estão associadas com os diferentes estágios de rotação de culturas e com as diferentes fases do crescimento da planta; ii) avaliar as habilidades de promoção de crescimento vegetal dos isolados bacterianos; iii) utilizar isolados selecionados em experimentos in vivo em casa de vegetação; iv) desenvolver um microarranjo para identificação de bactérias diazotróficas cultiváveis e conhecidas de diferentes ambientes. Os resultados obtidos pelo isolamento tradicional indicaram a presença de diferentes populações de PGPRs no solo rizosférico e no interior das raízes de canola nos diferentes estágios de rotação de cultura. Além disso, a estrutura da comunidade microbiana foi influenciada pela variação sazonal, como indicado pelos diferentes gêneros identificados nos diferentes estágios de desenvolvimento da planta, havendo, também, uma correlação positiva entre a diversidade bacteriana e a quantidade de precipitação mensal. Agrobacterium, Burkholderia, Enterobacter e Pseudomonas foram os gêneros bacterianos predominantes entre todos os identificados. Muitas das bactérias isoladas foram capazes de produzir compostos indólicos e sideróforos, solubilizar fosfato e algumas também foram capazes de fixar nitrogênio. Alguns dos isolados promoveram o crescimento da planta em casa de vegetação. Com relação ao microarranjo para identificação de bactérias diazotróficas cultiváveis e conhecidas de diferentes ambientes, apesar de terem sido realizados apenas testes preliminares, acredita-se que o microarranjo apresente um bom potencial para atingir o seu objetivo. Esse facilitará a busca por bactérias com propriedades de promoção de crescimento vegetal para a produção de um inoculante para as culturas de canola do sul do Brasil. / Plant growth promoting rhizobacteria (PGPR) can stimulate host plant growth through the production of plant-growth substances, suppression of deleterious organisms, availability and uptake of mineral nutrients and other activities. These bacteria have been the object of studies due to the effects produced in commercially important crops. Canola is an option for ground cover plant for crop rotation and the production of oil both as food and biodiesel. However, studies on the diversity of such microorganisms associated with canola crops and their potential to promote plant growth are scarce. Two studies were conducted in this work with the following objectives: i) isolate and identify culturable bacteria associated with rhizospheric soil and roots of canola (Brassica napus) to verify if possible changes in microbial communities were associated with different stages of crop rotation and the different stages of canola growth; ii) evaluate the PGP abilities of bacterial isolates iii) test some of the isolates for in vivo experiments in a greenhouse, iv) develop a microarray for identification of culturable diazotrophs in different environments. The results obtained by traditional isolation indicated the presence of a diverse population of PGPR in the rhizospheric soil and inside the roots of canola at different stages of crop rotation. Moreover, the microbial community structure was influenced by seasonal variation, as indicated by the different genera identified at different stages of canola development. There was also a relationship between bacterial diversity and monthly rainfall. Agrobacterium, Burkholderia, Enterobacter, and Pseudomonas were the prominent bacterial genera among all identified. Several of the isolated bacteria could produce indolic compounds and siderophores, to solubilize phosphate and some could also fix nitrogen. Some of the isolates were able to promote plant growth. Regarding the microarray, although only preliminary tests were performed, it was possible to show that the microarray has a good potential to achieve its goal. It will make easy the search for bacteria with properties of plant growth promotion for the production of an inoculant for canola cultivated in southern Brazil.

Orientador: Jose Tadeu Jorge / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-07-24T17:23:23Z (GMT). No. of bitstreams: 1 Vasconcelos_LuciaHelena_M.pdf: 2275752 bytes, checksum: b9684c1989694fb2123cab73bd031b48 (MD5) Previous issue date: 1998 / Resumo: A colza é uma semente oleaginosa, nativa do Oriente, que contém cerca 40% de óleo em sua composição. A variedade de colza (Brassica napus ou Brassica campestris), contendo baixos teores de ácido erúcico e glucosinalatos é chamada canola, cuja marca é registrada no Canadá. No Brasil, foi adaptada ao clima e ao solo no estado do Paraná, onde a primeira colheita se deu em 1992. Sendo uma semente oleaginosa, de grande interesse mundial para qual existe carência de informações, configura-se o interesse do conhecimento das propriedades fisicas da canola adaptada ao estado do Paraná, essencial para projeto de sistemas e equipamentos pós-colheita eficientes. Este trabalho teve por objetivos: determinar experimentalmente as curvas de equilíbrio higroscópico (adsorsão e dessorção) de canola a 25°, 35° e 45°C e correlacionar o dados obtidos ao modelo matemático proposto por HENDERSON e a uma equação de 3° grau; determinar as propriedades fisicas peso específico real e aparente, porosidade, ângulo de talude, velocidade terminal, perda de carga (correlacionar os dados obtidos desta propriedade ao modelo matemático de Sheed), coeficiente de atrito com superficies e atrito interno. As determinações realizadas com canola, variedade Iciola 41 da Cooperativa de Cafeicultores e Agropecuaristas de Maringá (COCAMAR), Paraná, com 7,03% de umidade (base úmida), apresentaram os seguintes resultados: peso específico aparente - 668 Kg/m3; peso específico real - 1183 Kg/m3; porosidade -43,53%; ângulo de talude - 30,60; velocidade terminal experimental - 622,30 crnls; velocidade terminal teórica -681,52 crn/s; - coeficiente de atrito com: chapa galvanizada - 0,251, madeirite - 0,402, concreto - 0,453, aço-inox - 0,261, alumínio - 0,351, atrito interno - 0,444; perda de carga - verificação do modelo de Sheed, com a determinação dos termos da equação, que resultou em altos coeficientes de correlação (mínimo 0,973) e significância no nível de 0,1%. Os dois modelos de ajuste por HENDERSON e a uma equação de 3° grau para isoterma de canoIa foram adequados respectivamente: com coeficiente de correlação de 0,995 e 0,998 e significância de 0,1%, a 25°C e para a adsorsão; 0,992 e 0,998 e significância de 0,1%, a 35°C e para adsorsão; de 0,985 e 0,999 e significância de 0,1%, a 25°C e para dessorção; 0,991 e 0,998 e significância de 0,1%, a 35°C e para dessorção / Abstract: The rapeseed is an oleaginous seed, native from the Orient, wich contains about 40% of oil in its composition. The rapeseed species (Brassica napus or Brassica campestris),wich contains lower erucic acid and glucosinalate leveles is called canola, a Canadian trade mark. In Brazil, after it was adapted to the climate and to the soil of State of Paraná, where the first harvest was carried in 1992. As the rapessed is an oleaginous seed of word interest, but there is not information, the knowledge about physical properties of canola adapted to Paraná is important im order to design post-harvest equipment. The objetives of this work were: to determine the equilibrium moisture content curves (adsorption and desorption) of canola at 25°, 35° and 45°C establish correlation with the mathematical model proposed by HENDERSON and to a 3rddegree equation; determine the physical properties, bulk and true density, porosity, angle of repose, terminal velocity, pressure drop (correlate the obtained data of this propertie tho Sheed's mathematical model), the five repetitions, coefficient of friction with surfaces: galvanized foil, plywood, concrete, inox steel, aluminum and internal coefficient of friction. The realized determinations with canola, Iciola 41 variety of Cooperativa de Cafeicultores e Agropecuaristas de Maringá (COCAMAR), Paraná, with 7,03% moisture conten, the results were: bulk density :- 668 kglm3;true density: - 1183 kglm3; porosity: _ 43,53%; angle of repose: - 30,60; experimental terminal velocity: - 622 crn/s; coefficients of friction on the surface with: galvanized foil: - 0,251; plywood:- 0,402; concrete: - 0,453; inox steel: - 0,261; aluminum: - 0,351; - internal friction: - 0,444; pressure drop - verifications of Sheed's model, with the determination of terms of equations, that results in high correlation coefficients (minimum 0,973) and signifying at the leveI of O,1%. The two adjusting models by HENDERSON and a 3rd degree equation for the isotherms canola were suitable with: correlation of 0,995 and 0,998 and signifying of 0,1% at 25°C for adsorption, 0,992 and 0,998 and signifying of 0,1% at 35°C for adsorption, 0,985 and 0,999 and signifying of 0,1% at 25°C for desorption, 0,991 and 0,998 and signifyingof 0,1% for desorption / Mestrado / Pre-Processamento de Produtos Agricolas / Mestre em Engenharia Agrícola

Orientador: Walter Esteves / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-19T14:27:33Z (GMT). No. of bitstreams: 1 Grimaldi_Renato_M.pdf: 2787190 bytes, checksum: 08a804e11884286b84b37e3e652bd2f4 (MD5) Previous issue date: 1994 / Resumo: O resumo podera ser visualizado no texto completo da tese digital / Abstract: The abstract is available with the full electronic digital document / Mestrado / Mestre em Tecnologia de Alimentos

Thesis (M. Sc. Agriculture (Soil Science)) -- University of Limpopo, 2016. / Canola (Brassica napus) is an important oil crop which is not well grown in Limpopo Province. Planting date is identified as a critical management decision in canola production for enhanced biological and economic returns as it has direct influence on the growing condition at which the crop is exposed to. The objective of the study was to determine the impact of planting date on growth, grain yield, oil content and economic returns on canola production as a winter crop option in the province. The study was conducted at two climatically diverse locations; the University of Limpopo experimental farm at Syferkuil and an Ofcolaco farmers’ field in 2013 and 2014. Canola was planted at four different dates (April, May, June and July) and (March, April, May) during 2013 and 2014 growing seasons, respectively, in a randomised complete block design (RCBD) under four replications, using AG-Muster cultivar. Weather parameters were obtained from Agricultural Research Council and University of Limpopo experimental farm. Plant parameters measured were days to seedling emergence, flowering and physiological maturity, plant height, number of main and sub branches, dry matter at onset of flowering and crop residues after threshing, number of pods per plant, number of seeds per pod, unshelled and shelled weight, and grain yield. The results revealed that, days to seedling emergence responded significantly (P≤0.01) and (P≤0.05) to planting date at both locations and years except in 2014 at Syferkuil. Plant height was significantly influenced by planting date in 2013 at both locations but in 2014, the effect was significant at maturity and flowering at Syferkuil and Ofcolaco respectively. At Ofcolaco, planting date influenced days to 50% flowering, physiological maturity and plant height in both growing seasons. The influence of planting date on days to flowering and physiological maturity was significant (P≤0.01) at both locations and seasons. Canola dry matter accumulation at flowering responded significantly (P≤ 0.01) to planting date only at Syferkuil in 2013 across seasons and locations whereas residue after seed threshing responded significantly at both locations and seasons. Grain yield was significantly (P≤0.01) influenced by planting dates at all locations and seasons ranging from 292 to 2983 kg ha-1. At Syferkuil, planting canola not later than April resulted in higher grain yield whereas at Ofcolaco, planting between April and May produced the highest grain yield. The number of pods per 2 plant influenced grain yield more than the other yield components studied and regarding weather variables, minimum temperature was found to be most important in influencing growth and grain yield of canola. Oil yield ranged from 155 to 539 kg ha-1 at Syferkuil, in 2013 whilst in 2014, the range was 252 to 614 kg ha-1. At Ofcolaco, significant response of oil yield to planting dates was observed in both seasons. Economic returns at Syferkuil ranged from -R6213.00 to +R2130.00 whereas at Ofcolaco the range was +R793.00 to +R6555.00. The study revealed that Ofcolaco appeared to be better suited for canola production compared to Syferkuil due to higher grain yield and positive economic returns at the former. Keywords: canola; grain yield; oil yield; plant density, planting dates, weather parameters. / The National Research Foundation (NRF) through the Risk and Vulnerability Science Centre (RVSC). VLIR-IUC Programme.

Thesis (MScAgric)--Stellenbosch University, 2014. / ABSTRACT ENGLISH: Canola is increasingly becoming an important economic field crop in South Africa, because it can be used to produce high quality cooking oil and margarine, animal feed, biofuel and in crop rotation systems to break the disease cycle and improve weed management. Effect of temperature on phenological responses with respect to required number of days, growing degree days, photothermal units to specific growth stages, growth rate, as well as vegetative and reproductive growth of canola were studied under controlled conditions. Seven canola cultivars selected from early and mid-maturing groups of canola cultivars, presently planted in the Western Cape canola production area, were grown in 3 litre plastic bags filled with a mixture of sand and compost at ratio of 1:1 and irrigated with fully balanced nutrient solution at EC=2.0 in two glasshouses at night/day temperature regimes of 10/15oC and 15/20oC. Number of days, growing degree days (GDD) and photothermal units (PTU) from planting to seedling emergence, first true leaf appearance, visible flower buds, first flower opening, seed ripening and seed physiological maturity were recorded. Plant heights were measured at 14 day intervals from 28 to 84 days after planting (DAP). Plants were sampled for leaf area (LA) and above ground dry mass (DM) at budding, flowering and seed physiological maturity. Plant growth rates (PGR) from planting to budding, from budding to flowering and from flowering to physiological maturity were calculated. Relative growth rates (RGR) and net assimilation rates (NAR) from budding to flowering and from flowering to physiological maturity were also calculated. Days after planting, GDD and PTU at budding, flowering and physiological maturity were correlated with leaf area, dry mass, number of pods plant-1 and pod dry mass plant-1 at budding, flowering and physiological maturity to determine whether there were relationships between the variables. The study showed that by increasing night/day temperature from 10/15⁰C to 15/20⁰C plant height, number of leaves plant-1 at budding stage, leaf area at budding , plant growth rate (PGR) from planting to budding stage and relative growth rate (RGR) from budding to flowering stage were increased. However, PGR from budding to physiological maturity, RGR from flowering to physiological maturity, net assimilation rate (NAR) from budding to flowering stage, leaf area at flowering and physiological maturity stages , as well as number of flower stems, number of pods plant-1, above ground total dry mass at flowering and physiological maturity stages were decreased. Pod dry mass at physiological maturity decreased by 22.24% to 40.35% for different cultivars which clearly demonstrated the sensitivity of canola cultivars to increasing night/day temperatures. By increasing the mean daily mean temperature from 12.5⁰C (10/15⁰C night/day) to 17.5⁰C (15/20 ⁰C night/day) the duration of the period from planting to seedling emergence as well as the vegetative and reproductive growth stages were decreased. With the exception of the vegetative growth stage, GDD and PTU requirements to reach specific growth stages increased with an increase in temperature. Plant growth parameters such as dry mass, leaf area, number of pods plant-1 and pod dry mass plant-1 at specific growth stages showed a positive correlation with the number of days needed to reach that growth stage, but not with GDD or PTU requirements. Although the responses of cultivars to increasing temperatures did differ for most parameters measured, responses did not always correlate with the maturity grouping of cultivars, suggesting that responses to temperature may to a large extent be determined by the genetic make-up (breeding company) of cultivars. These results indicate that number of days, GDD and PTU requirements to reach physiological maturity may be used to describe the cultivar maturity groupings, but because of the effect of temperature and day length, GDD and PTU should be more accurate. / AFRIKAANSE OPSOMMING: Canola se waarde as ekonomies belangrike akkerbou-gewas in Suid-Afrika het die afgelope aantal jare skerp toegeneem, omdat dit gebruik kan word om hoë kwaliteit kook-olie en margariene asook bio-brandstowwe en dierevoere, te vervaardig. In wisselboustelsels kan dit gebruik word om die siekte-ketting te breek en onkruidbeheer te vergemaklik. In hierdie studie is die invloed van temperatuur op die fenologiese reaksies van canola in terme van die aantal dae, gewasgroeidae en fototermiese eenhede, benodig om spesifieke groeistadiums te bereik, asook die invloed op groeitempo, vegetatiewe- en reproduktiewe groei onder gekontroleerde toestande nagevors. Sewe canola cultivars vanuit die kort en mid-groeiseisoen volwassenheidsgroepe wat tans in die Weskaap verbou word is geplant in 3-liter plastiek houers gevul met „n 1:1 sand: kompos mengsel as groeimedium en besproei met „n volledig gebalanseerde voedingsoplossing met EC=2.0. Twee glashuise met nag/dag temperature van onderskeidelik 10/15oC en 15/20oC is vir hierdie doel gebruik. Die aantal dae, gewasgroeidae (GGD) en fototermiese eenhede (FTE) wat vanaf plant tot saailingverskyning; eerste volwasse blaarverskyning; eerste blomknop verskyning; eerste blom; saad verkleuring en fisiologies volwasse stadiums vereis word, is bepaal. Plant lengte is gemeet met 14-daagse tussenposes vanaf 28 tot 84 dae na plant. Plante is gemonster is tydens die eerste blomknopverskyning asook blom- en fisiologies volwasse stadiums om blaaroppervlakte (BO) en droëmassa (DM) te bepaal. Plant groeitempos (PGT) vanaf plant tot blomknopverskyning; blomknopverskyning tot blom en vanaf blom tot fisiologiese volwasse stadium is bereken. Relatiewe groeitempos (RGT) en netto-assimilasietempos (NAT), is bereken vanaf blomknopverskyning tot blom en vanaf blom tot fisiologiese volwasse stadium. Die aantal dae vanaf plant, asook GGD en FTE benodig om blomknopstadium, blomverskyning en fisiologies volwasse stadiums te bereik, is gekorreleer met BO en DM plant-1 asook die aantal peule en peulmassa plant-1 tydens genoemde groeistadia om moontlike verwantskappe te bepaal. Die studie het getoon dat deur die nag/dag temperatuur te verhoog vanaf 10/15⁰C tot 15/20⁰C, plant lengte, aantal blare en BO plant-1 tydens blomknopverskyning, asook PGT vanaf plant tot blomknopverskyning en RGT van blomknopverskyning tot blomstadium, toeneem. Daarteenoor het PGT van blomknopverskyning tot fisiologies volwassenheid, RGT van blom tot fisiologies volwassenheid, asook NAT van blomknopverskyning tot blomstadium en BO tydens blom en fisiologies volwasse stadium, afgeneem. Reproduktiewe ontwikkeling soos gemeet aan die aantal bloeistele, peule plant-1 en peulmassa plant-1 is ook benadeel deur genoemde verhoging in temperatuur. Die afname in peulmassa het gewissel tussen 22.24% en 40.35% vir verskilende cultivars en is „n duidelike aanduiding van die verskillende canola cultivars se gevoeligheid teenoor toenemende nag/dag temperature. Die toename in gemiddelde nag/dag temperatuur vanaf 12.5⁰C (10/15⁰C) tot 17.5⁰C (15/20 ⁰C) het die aantal dae vanaf plant tot saailing verskyning asook die vegetatiewe en reproduktiewe groei fases verkort. Met die uitsondering van die vegetatiewe groei fase, het die GGD and FTE vereistes om spesifieke groeistadiums te bereik toegeneem met „n toename in temperatuur. Plant komponente soos DM, BO, aantal peule plant-1 en peulmassa plant-1 tydens spesifieke groeistadia het „n positiewe verwantskap getoon met die aantal dae wat benodig is om spesifieke groeistadiums te bereik, maar sodanige verwantskap is nie bevestig met GGD en FTE vereistes. Hoewel die reaksie van verskillende cultivars teenoor „n toename in temperatuur vir die meeste gemete plantkomponente verskil het, het die reaksie nie altyd verband gehou met die volwassenheidsgroepering van die cultivars. Dit wil dus voorkom asof die reaksie teenoor temperatuur tot „n groot mate ook verband hou met die genetiese samestelling van die cultivar soos bepaal deur die telingsmaatskappy. Hierdie resultate toon dat die aantal dae, GGD en FTE wat vereis word om fisiologiese volwassenheid te bereik gebruik kan word om die cultivar se volwassenheidsgroepering te beskryf maar dat GDD en FTE waarskynlik meer akuraat sal wees weens effek van temperatuur en daglengte op die ontwikkkeling van cultivars.

Thesis (PhD(Agric))--Stellenbosch University, 2012. / ENGLISH ABSTRACT: There is an increasing demand for canola (Brassica napus L.), an emerging oilseed crop in South Africa. Canola thrives in the Western Cape. However, yet low yields are still obtained within the production areas with poor and or variable responses to nitrogen applications. Crop nutrition and specifically the contribution of sulphur (S) to nitrogen (N) use and selection of nutrient efficient genotypes can be strategies of considerable significance in increasing yields. This study investigated growth, yield and quality responses of canola to different N (0, 30, 60, 90 and 120 kg N ha-1) and S (0, 15 and 30 kg S ha-1) fertilisation rates in field trials at different localities, during the 2009-2011 period. Responses to N and S under optimum growing conditions and responses of different cultivars were investigated in unison in glasshouse trials at the Department of Agronomy of the University of Stellenbosch. Locality and growing season (year) significantly affected nutrient content in plants at flowering (90 days after planting), dry mass production as well as yield and quality of canola in field trials at five different localities during the 2009-2011 period. Growth and yield were also affected by N application rate in both field and glasshouse trials. Sulphur applications did not have an effect on vegetative growth, but rather stimulated flower and pod production in glasshouse trials and resulted in higher grain yields in field trials. Response depends largely on rainfall and S content of the soil. Highest yields were, on average, obtained with application rates of 120 kg N and 30 kg S ha-1, while glasshouse trials showed that even higher rates may be considered under optimum growing conditions. High application rates of N and S also improved water use efficiency from approximately 4-5 kg grain yield to about 8-9 kg grain yield mm-1 of rain during the growing season. Agronomic efficiencies of applied N decreases with increasing N rates and values of about 8 kg grain yield increase per kg of N applied at N rates of 120 kg N ha-1 indicated that high N rates may improve profit margins of canola as long as the cost of N is not more than eight times the producers price of canola. Agronomic efficiencies of N applications are improved if 15 kg S ha-1 is applied complimented with high rainfall, but not with applications of 30 kg S ha-1. Improved agronomic efficiencies of S applications shown at higher N rates, confirmed the dependency of S responses to sufficient availability of nitrogen. Sulphur applications, in contrast to N, resulted in an increase in oil content of the grain in field trials. Yield responses of different cultivars to nitrogen fertilisation under glasshouse conditions differed, with better responses obtained within short and medium season cultivars, than with a late maturing (long season cultivar), in spite of a better vegetative (dry mass) response of the later maturing cultivar. These results may indicate differences in the growth habit of different cultivars, but more research in this regard is needed. / AFRIKAANSE OPSOMMING: Canola (Brassica napus L.), ‘n relatief nuwe oilsaadgewas wat goed aangepas is, word in ‘n toenemende mate in die produksiegebiede van die Weskaap verbou. Lae opbrengste en wisselvallige reaksies teenoor stikstofbemesting word egter verkry ten spyte van die gewas se hoë stikstofbehoefte en dit mag moontlik aan swaweltekorte toegeskryf word. In hierdie ondersoek is die groei-, opbrengs- en kwaliteitsreaksie van canola teenoor verskillende N (0, 30, 60, 90 en 120 kg N ha-1) en S (0, 15 en 30 kg S ha-1) bemestingspeile in droëland proewe op verskillende lokaliteite bestudeer gedurende die 2009-2011 groeiseisoene. Reaksies teenoor N en S onder optimale groeitoestande en vir verskillende cultivars is in glashuisproewe van die Departement Agronomie van die Universiteit van Stellenbosch, uitgevoer. Die chemiese samestelling van die plante tydens blomstadium (90 dae na plant), asook droëmateriaal produksie, graanopbrengs en kwaliteit het betekenisvol verskil tussen die lokaliteite, maar lokaliteitsverskille is ook deur die seisoene beïnvloed. Die ontwikkeling, groei en graanopbrengs van die canola is ook beïnvloed deur die stikstofbemestingspeile in beide die veld en glashuisproewe. Swawelbemesting het nie die vegetatiewe groei van canola beïnvloed nie, maar het blom en peulproduksie in glashuisproewe en graanopbrengste in veldproewe verhoog. Die reaksie van canola teenoor die swawelbemesting is grootliks bepaal deur die swawelinhoud van die grond asook klimaatsfaktore soos reënval. In die algemeen is die hoogste canola opbrengste in veldproewe met toedienings van 120 kg N en 30 kg S ha-1 verkry, maar glashuisproewe het getoon dat hoër toedieningspeile nodig mag wees onder optimale groeitoestande soos in besproeiingsgebiede. Hoë toedieningspeile van N en S het veroorsaak dat die waterverbruiksdoeltreffendheid toegeneem het van 4-5 kg graanopbrengs per mm reën tot sowat 8-9 kg graan opbrengs per mm reën. Agronomiese doeltreffendheid van toegediende stikstofbemesting het afgeneem met toenemende N peile, maar waardes van ongeveer 8 kg opbrengsverhoging per kilogram N toegedien met stikstofpeile van 120 kg ha-1, toon dat hoë N toedieningspeile mag steeds winsgrense verhoog mits die prys van een kilogram N nie meer is as agt maal die produsente prys van canola is nie. Agronomiese doeltreffendheid van stikstofbemesting is verhoog deur ook 15 kg S per hektaar toe te dien, maar nie deur die toediening van 30 kg S ha-1 nie. Die agronomiese doeltreffendheid van S toedienings het slegs by die gelyktydige toediening van hoë stikstoftoedienings toegeneem, wat die wisselwerking tussen N en S ten opsigte van graanopbrengs bevestig. In teenstelling met stikstof het swawel toedienings die olie-inhoud van canola in die veldproewe verhoog. In glashuisproewe is gevind dat kort en medium groeiseisoen cultivars, ten spyte van ‘n groter vegetatiewe reaksie van die lang groeiseisoen cultivars, groter opbrengsreaksies teenoor stikstof- en swawelbemesting toon. Meer navorsing word egter in hierdie verband benodig.

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