Thesis (Ph.D.)--University of Alberta, 2010. / Title from PDF file main screen (viewed on May 27, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Plant Science, [Department of] Agricultural, Food and Nutritional Science, University of Alberta. Includes bibliographical references.

Thesis (MScAgric)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The influence of chemical seed treatments on the germination, seedling survival and yield of canola (cv. Varola 44) was investigated in a series of incubation studies, glasshouse experiments, as well as field trials in the canola producing areas in the Western Cape Province. Incubation experiments were conducted to compare germination and seedling growth of untreated (control) seed with that of seed treated at different application rates (0.5, 1.0 and 2.0 times the recommended) of Cruiser® and SA-combination (which consists of Thiulin® at 0.5g a.i.; Apron® at 0.0815 g a.i.; Gaucho® at 0.6125 g a.i. and Rovral® at 0.9975 g a.i.). The results indicated that seed treatment (all rates of SA-combination and highest rate of Cruiser) delayed germination and seedling growth, especially if the seed was subjected to the Accelerated Ageing Test. Glasshouse studies with pasteurised soil at different water contents, seed sources (storage periods) and planting depths confirmed the phytotoxic effects of the chemical seed treatments in the absence of soil borne pathogens. From the results it became clear that extreme water conditions (very wet or dry) increased the suppressing effect on germination and seedling growth, but that no phytotoxic reactions occurred in moist (favourable soil water conditions) soil, regardless of application rate of the chemicals used, planting depth and seed source. In a second glasshouse experiment conducted in moist soil (kept at 50% of field water capacity to prevent any toxic effects) from seven different localities that were naturally infested with pathogens, both chemicals proved to be effective where soil borne pathogens (Rhizocfonia so/ani and Pythium spp.) occurred. No clear trend could however be found due to either chemical or application rates used. Finally, field trials were conducted to study the effect of chemical seed treatments on the plant populations and yield of canola planted in different row widths (17 and 34 cm) and seeding rates (3, 5 and 7 kq.ha'). Results showed that treated seeds produced more plants.rn" and yielded more than untreated seeds at Roodebloem Experimental Farm, while the highest seeding rate produced significantly more plants.rn" (Roodebloem and Langgewens Experimental Farms), but not significantly higher yields than the lowest seeding rate at the same locality. Although row width did not have an effect on plant population, yield (Roodebloem 2003) was significantly less at the wider (34 cm) rows. As in earlier experiments, no consistent differences between the two chemicals used were found. These results clearly illustrated both the negative (in the absence of pathogens) and positive (where soil borne pathogens do occur) effects that chemical seed treatments may have on the germination, seedling growth and even yield of canola under local environmental and soil conditions. Because no significant differences were found between the chemicals used, both chemicals should be regarded as efficient. More research, especially under field conditions and with more cultivars, is needed before the registration of a chemical for seed treatment could be considered. / AFRIKAANSE OPSOMMING: Die invloed van chemiese saadbehandeling op die ontkieming, saailing oorlewing en opbrengs van canola (cv. Varola 44) is ondersoek in 'n reeks inkubasie studies, glashuis eksperimente en veldproewe in die canolaproduserende gebiede in die Wes Kaap Provinsie. Inkubasie eksperimente is uitgevoer om die ontkieming en saailing groei van onbehandelde (kontrole) saad te vergelyk met dié van saad wat behandel is teen verskillende dosisse (0.5, 1.0 en 2.0 keer die aanbevole) van Cruiser® en SA-kombinasie (wat bestaan uit Thiulin® teen 0.5g a.i.; Apron® teen 0.0815 g a.i.; Gaucho® teen 0.6125 g a.i. en Rovral® teen 0.9975 g a.i.). Die resultate het aangedui dat saadbehandeling (vir alle dosisse van SAkombinasie en die hoogste dosis van Cruiser) ontkieming en saailing groei vertraag, veral wanneer die saad onderwerp was aan die Versnelde Verouderings Toets. Glashuis studies met gepasteuriseerde grond by verskillende waterinhoude, saad bronne (stoor periodes) en plantdieptes, het die fitotoksiese effekte van die chemiese saadbehandelings bevestig in die afwesigheid van grondgedraagde patogene. Vanuit die resultate het dit duidelik geword dat ekstreme water toestande (baie nat of droog) die onderdrukkende effek op ontkieming en saailinggroei verhoog het, maar dat geen fitotoksiese reaksies plaasgevind het in klam (gunstige grondwater toestande) grond nie, ongeag die dosisse of chemikalieë gebruik, plantdiepte en saad bron. In 'n tweede glashuis eksperiment uitgevoer in klam grond (gehou by 50% van veldwaterkapasiteit om toksiese effekte te voorkom) van sewe lokaliteite wat natuurlik besmet was met patogene, was beide chemikalië effektief waar grondgedraagde patogene (Rhizoctonia so/ani en Pythium spp.) voorgekom het. Geen duidelike tendens is egter waargeneem vir enige van die chemikalieë of dosisse nie. Laastens is veldproewe uitgevoer om die effek van chemiese saadbehandelings op plant populasies en opbrengs te bepaal van canola geplant in verskillende rywydtes (17 en 34 cm) en saaidigthede (3, 5 en 7 kg.ha-1). Resultate het aangedui dat behandelde saad meer plante.rn" produseer en 'n groter opbrengs lewer as onbehandelde saad by Roodebloem Eksperimentele Plaas, terwyl die hoogste saaidigtheid betekenisvol meer plante.m" (Roodebloem en Langgewens Eksperimentele Plase), maar nie betekenisvol hoër opbrengste gelewer het as die laagste saaidigtheid by dieselfde lokaliteit nie. AI het rywydte nie 'n effek op plant populasie gehad nie, was opbrengs (Roodebloem 2003) betekenisvol minder by die wyer (34 cm) rye. Soos in vroeëre eksperimente is geen konsekwente verskille tussen die twee chemikalieë gevind nie. Hierdie resultate illustreer duidelik beide negatiewe (in die afwesigheid van grondgedraagde patogene) en positiewe (in die aanwesigheid van grondgedraagde patogene) effekte wat chemiese saadbehandelings op ontkieming, saailing groei en selfs opbrengs van canola onder plaaslike omgewings en grondtoestande kan hê. Omdat geen betekenisvolle verskille tussen die chemikalieë gevind is nie, moet beide chemikalieë as doeltreffend aanvaar word. Meer navorsing, veralonder veldtoestande en met meer kultivars, is egter nodig voordat die registrasie van 'n chemiese middel vir saadbehandeling oorweeg kan word.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Glufosinate ammonium is one of the most widely-applied broad-spectrum herbicides, controlling weeds in a huge variety of crops worldwide. Farmers rely on glufosinate ammonium because it ensures a high degree of crop safety, as it only affects the parts of the plant where it is applied. It is effective against a broad range of weeds, eliminating the need to apply several herbicides to control different weeds in a given crop. Its unique mode of action makes it ideal to be used in rotation with other herbicides to mitigate weed resistance. Despite these favourable attributes for weed control glufosinate ammonium has its shortcomings. Glufosinate ammonium is a post emergence herbicide and its efficacy is not exempt from the effect of environmental/climatic conditions and the growth stage of weeds. The possible effect of these factors on the performance of the herbicide was investigated in a glasshouse study using ryegrass (Lolium spp) as the test species. The investigation consisted of four experiments. The first two experiments investigated the effect of applying different doses of glufosinate ammonium to commercial ryegrass and weedy ryegrass seedlings at different growth stages in a glasshouse. The glufosinate ammonium dosage rates were 0, 2.5, 5, 7.5 and 10 L ha-1. The findings of the studies showed that neither plant age nor herbicide rate affected the efficacy of glufosinate ammonium in a commercial cultivar or weedy type ryegrass. There were no statistically significant differences between the percentage mortality caused by any of the glufosinate ammonium dosage rates between 2.5 and 10 L ha-1 with the percentage control being higher than 90% at all dosage rates in both experiments. The objective of the third and fourth experiment was to determine the effect of temperature on the efficacy of ryegrass control by glufosinate ammonium. The temperatures for the third experiment were 10/15 0C (cool) and 15/20 0C (warm) night/day and for the fourth experiment 10/15 0C (cool) and 20/25 0C (warm) night/day. The glufosinate ammonium dosage rates applied were 0, 2.5, 5, 7.5 and 10 L ha-1. Plants in the third experiment remained in the glasshouse throughout the study at a constant temperature regime. Under cool temperatures glufosinate ammonium controlled ryegrass plants, irrespective of the rate applied, with 100% control achieved at a dosage rate of 2.5 L ha-1. This was not the case under warm temperatures where 100% control was not even achieved at the 10 L ha-1 dosage rate. In the fourth experiment cool and warm temperature regimes were applied before and after spraying. The four temperature treatments applied were therefore cool (10/15 ºC), warm (20/25 ºC), cool/warm (where the plants were moved from the cool temperature to the warm one after spraying) and warm/cool (which was the opposite of cool/warm). The results observed from the fourth experiment followed the same trend as in experiment three. Ryegrass plants that were grown under warm temperature and moved to cool temperature after spraying were better controlled than under cool/warm temperatures. Dosage rates of 2.5 L ha-1 gave 95% control of ryegrass under cool temperatures whereas the same dosage rate only achieved about 55% control under warm temperatures. Glasshouse and field trials were conducted at Stellenbosch University experimental farm Welgevallen (33°56’S, 18°42’E) to investigate the effect of the additive ammonium sulphate (AMS) on the efficacy of glufosinate ammonium. The glasshouse trial consisted of four ryegrass populations (one commercial cultivar (Lolium multiflorum cv Agri Hilton) and three suspected resistant weedy types (Lolium spp.) The temperature of the glasshouse was 20/25 0C night/day. The four ryegrass populations were each subjected to an experiment using a 7 x 2 factorial design with seven dosage rates (0, 0.75, 1.5, 3, 4.5, 6 and 7.5 L ha-1 of glufosinate ammonium) and two AMS treatments (with and without AMS) laid out in a randomized complete block design with three replicates. The AMS increased the efficacy of glufosinate ammonium on the commercial cultivar and resistant population 2 at certain critical dosage rates. The field trials were conducted in 2013 and 2014. The trials were arranged factorially in a randomised complete block design replicated four times. The treatment factors were two treatments (glufosinate ammonium alone and glufosinate ammonium plus AMS) and five glufosinate ammonium rates (0, 2.5, 5, 7.5, and 10 L ha-1 of glufosinate ammonium). Ammonium sulphate (10 g) was diluted in 1 L of distilled water before mixing with glufosinate ammonium. The findings of the study revealed that AMS increased the efficacy of glufosinate ammonium under field conditions in 2013 but not in 2014. Experiments with the aim of determining the effect of propyzamide on the efficacy of four herbicides (atrazine, glufosinate ammonium, glyphosate and imazamox) was carried out in a glasshouse as well as in field studies. In the glasshouse study, ryegrass was used as a test species. The four herbicides and propyzamide were applied separately, followed by mixtures with propyzamide at the rates of 0, 0.5, 0.75 and 1x (times the recommended rate) for each of the herbicides in the mixture. Results suggest that propyzamide negatively affected atrazine efficacy on ryegrass in the glasshouse but not the efficacy of any other herbicides. Field experiments were conducted to determine the effect of adding propyzamide to the four herbicides on the efficacy and residual action of the herbicides in 2012, 2013 and 2014. Field trials were conducted at Welgevallen, Roodebloem and Langgewens experimental farms. The experimental design was a randomised complete block with nine treatments replicated four times. Propyzamide increased the efficacy of atrazine in some of the field trials as well as the efficacy of imazamox in some trials but generally the results were variable and propyzamide also did not enhance the residual action of the herbicides in most of the trials / AFRIKAANSE OPSOMMING: Glufosinaat ammonium is een van die mees algemene breëspektrum nie-selektiewe onkruiddoders wat onkruide in ‘n groot verskeidenheid gewasse wêreldwyd beheer. Boere maak staat op glufosinaat ammonium omdat dit redelik veilig vir die gewas is as gevolg van die feit dat dit slegs die gedeelte van die plant waarmee dit in aanraking kom, affekteer. Dit is effektief teen ‘n wye verskeidenheid van onkruide wat dit onnodig maak om verskeie onkruiddoders te gebruik om verskillende onkruide in ‘n gewas te beheer. Die unieke meganisme van werking maak dit ideaal om in afwisseling met ander onkruiddoders te gebruik om onkruiddoderweerstand te bestuur. Ten spyte van al hierdie voordele het glufosinaat ammonium ook verskeie tekortkominge. Glufosinaat ammonium is ‘n na-opkoms onkruiddoder en sy effektiwiteit word beïnvloed deur omgewings- of klimaatstoestande en die groeistadia van onkruide. Die moontlike invloed van bogenoemde faktore op die effektiwiteit van glufosinaat ammonium is in ‘n glashuisstudie ondersoek waar raaigras (Lolium spp) as toetsspesie gebruik is. Die ondersoek het uit vier eksperimente bestaan. Die eerste twee eksperimente het die effek van verskillende toedieningsdosisse van glufosinaat ammonium op raaigrassaailinge van ‘n kommersiële kultivar asook ‘n onkruidbiotipe op verskillende groeistadia ondersoek. Die glufosinaat ammonium dosisse was 0, 2.5, 5, 7.5 en 10 L ha-1. Die resultate het getoon dat nie die toedieningsdosis of die plantgroeistadium die effektiwiteit van glufosinaat ammonium op die kommersiële raaigras kultivar of die onkruid biotipe beïnvloed het nie. Daar was nie enige statisties betekenisvolle verskille tussen die persentasie mortaliteit veroorsaak deur enige van die glufosinaat ammonium dosisse tussen 2.5 en 10 L ha-1 nie en die persentasie beheer was hoër as 90% by alle toedieningsdosisse in beide populasies. Die derde en vierde eksperimente is gedoen om vas te stel of temperatuur ‘n rol speel in die effektiwiteit van glufosinaat ammonium op raaigras beheer. Die temperature vir die derde glashuisproef was gestel op 10/15 ºC (koel) en 15/20 ºC (warm) nag/dag temperature en vir die vierde glashuisproef was dit 10/15 ºC (koel) en 20/25 ºC (warm). Die glufosinaat ammonium toedieningsdosisse was 0, 2.5, 5, 7.5 and 10 L ha-1. Die plante in die derde eksperiment het in die onderskeie glashuise by dieselfde temperatuur gebly deur die loop van die hele eksperiment. Onder koel toestande het glufosinaat ammonium die raaigrassaailinge 100% beheer selfs by die laagste toedieningsdosis van 2.5 L ha-1 en by alle dosisse bo dit. By warmer temperature egter, kon selfs die hoogste dosis van 10 L ha-1 nie 100% beheer behaal nie. Die vierde eksperiment was soortgelyk aan die derde eksperiment behalwe dat die koel en warmer temperature afgewissel is voor en na die plante bespuit is. Die vier temperatuurbehandelings was dus koel (10/15 ºC), warm (20/25 ºC), koel/warm (waar die plante na spuit van die koel na die warm glashuis verskuif was) en warm/koel (die teenoorgestelde van die koel/warm behandeling). Die resultate wat waargeneem is het dieselfde tendens getoon as die resultate van die derde eksperiment. Toedieningsdosisse van 2.5 L ha-1 het 95% beheer van raaigras wat onder koel toestande gegroei het getoon terwyl dieselfde dosis onder die warm toestande slegs 55% beheer behaal het. Glashuis- en veldproewe is uitgevoer op die Welgevallen proefplaas van die Universiteit van Stellenbosch (33°56’S, 18°42’O) om die invloed van die byvoeging van ammoniumsulfaat (AMS) op die effektiwiteit van glufosinaat ammonium te ondersoek. In die glashuisproef was vier populasies raaigras (een kommersiële kultivar Lolium multiflorum cv Agri Hilton) en drie vermoedelik weerstandbiedende onkruidpopulasies (Lolium spp) gebruik. Die temperatuur van die glashuis was op 20/25 0C nag/dag ingestel. Die vier raaigras populasies was elk blootgestel aan ‘n faktoriaal gereëlde 7 x 2 eksperiment met sewe toedieningsdosisse (0, 0.75, 1.5, 3, 4.5, 6 en 7.5 L ha-1 glufosinaat ammonium) en twee AMS behandelings (met en sonder AMS) wat in ‘n volledige ewekansige blokontwerp met drie herhalings uitgelê is. Die AMS het die effektiwiteit van glufosinaat ammonium slegs op die kommersiële kultivar en een van die vermoedelik weerstandbiedende populasies verhoog by ‘n sekere kritiese toedieningsdosis. Die veldproewe is in 2013 en 2014 uitgevoer. Die proewe is faktoriaal uitgelê in ‘n volledig ewekansige blokontwerp wat vier keer herhaal is. Die behandelingsfaktore was twee behandelings (glufosinaat ammonium met en sonder AMS) en vyf glufosinaat ammonium toedieningsdosisse (0, 2.5, 5, 7.5, en 10 L ha-1 glufosinaat ammonium). Die AMS (10 g) is in 1 L gedistilleerde water opgelos voordat dit met die glufosinaat ammonium oplossing vermeng is. Die resultate het getoon dat die AMS die effektiwiteit van glufosinaat ammonium onder veldtoestande slegs in 2013 betekenisvol verbeter het maar nie in 2014 nie. Proewe met die doel om die effek van propisamied op die effektiwiteit van vier onkruiddoders (atrasien, glufosinaat ammonium, glifosaat en imasamoks) te bepaal is uitgevoer in die glashuis sowel as in die veld. In die glashuisstudie is die onkruiddoders op raaigras saailinge toegedien. Die vier onkruiddoders en propisamied is alleen toegedien en dan is elk van die vier onkruiddoders ook gemeng met propisamied teen die toedieningsdosisse van 0, 0.5, 0.75 en 1.0 keer die aanbevole dosis (x) van elk van die bestanddele van die mengsel. Die resultate dui aan dat propisamied die werking van atrasien op raaigras negatief beïnvloed het maar nie die werking van enige van die ander onkruiddoders nie. Veldeksperimente is uitgevoer om die effek van propisamied op die effektiwiteit en residuele aksie van die onkruiddoders onder veldtoestande in 2012, 2013 en 2014 te bepaal. Die veldproewe is uitgevoer op die Welgevallen, Langgewens en Roodebloem proefplase. Die proefontwerp was ‘n volledig ewekansige blokontwerp met nege behandelings wat vier keer herhaal is. Propisamied het die effektiwiteit van atrasien in sekere lokaliteite verbeter asook die van imasamoks in sekere proewe maar die resultate was oor die algemeen wisselvallig. Byvoeging van propisamied by die onkruiddoders het in die meeste gevalle nie die residuele werking daarvan verbeter nie.

Master of Science / Department of Agronomy / Kraig Roozeboom / Winter survival of canola (Brassica napus L.) is a challenge for producers using high-residue, no-tillage, or reduced tillage systems. In addition, as hybrid cultivars have become more available in recent years, this has brought about questions regarding best management practices to aid in mitigating winter survival challenges associated with high residue production systems. Overcoming production challenges will allow producers to diversify their no-till cropping systems with an oil seed crop having strong domestic demand. This research was undertaken to identify practices that could improve performance of canola in high-residue cropping systems. Two sets of experiments were conducted at twelve sites across Kansas from 2014 to 2016 to evaluate practices that could improve stand establishment, winter survival, and yield of winter canola. The objective of the first study conducted at 10 site years was to determine the effect of residue management, seeding density, and row spacing on stand establishment, winter survival, and yield. An innovative residue management system being developed by AGCO Corp. was compared to cooperating canola producers’ no-till residue management and planting methods in wheat residue. This on-farm experiment was conducted at ten environments across Kansas. AGCO treatments were 20 or 30-in row spacing and three seeding rates for a total of six treatments. Producer treatments included their preferred row spacing, seeding rate, and residue management practices. Winter survival increased by 11% to 29% as seeding rate decreased in 20-in rows at four of the five harvested environments. At Stafford and Kingman, the lowest yielding AGCO treatment produced 3.7 to 4.2-bushel acre⁻¹ more than the respective cooperator treatments. Reduced seeding rates in the AGCO system produced yields similar to or superior than the cooperator practice in all environments. Producers have been turning to planting canola in wide rows to facilitate residue management with strip tillage or planter residue management attachments. The objective of the second study conducted at three site-years was to determine the effect of seeding rate on winter survival and yield of hybrid and open-pollinated winter canola cultivars in 30-in rows. Treatments were four genotypes and five seeding rates for a total of twenty treatments. Winter survival increased with the lowest seeding rate at one of the three environments. At two of the three environments neither genotype nor seeding rate affected yield. These results indicate that seeding rates can be reduced from those typically used by canola producers in high residue, no-till or reduced tillage systems if residue can be adequately removed from the seed row. Both hybrid and open-pollinated winter canola cultivars responded similarly to seeding rate in 30-in rows in these experiments, indicating that similar seeding rates could be used for each type of cultivar. Management practices such as, narrow row spacing, reducing seeding rates, and adequately managing residue at planting may result in small improvements to establishment, winter survival and yield.

The exotic cabbage maggot (CM) infests canola on the prairies, feeding on roots in its larval stage, which disrupts the uptake of nutrients and water and provides an entry point for fungal plant pathogens. The European staphylinid, Aleochara bipustulata L., may be introduced for control of CM, but only if the risk to other species is low and if A. bipustulata has demonstrable potential to increase mortality already caused by natural enemies in Canada. Aleochara bipustulata could contribute to pest management as a predator of CM eggs and larvae, and as a parasitoid of CM puparia; however, it could affect non-pest species in the same two ways. A variety of invertebrates that share the soil of Brassica fields with immature CM were screened in laboratory no-choice assays to determine what adult A. bipustulata eat. In these assays, immobile or barely mobile invertebrates were accepted regularly and could be at risk. The majority of groups were seldom or never consumed. Also, a molecular assay developed to test for CM DNA in the guts of field-collected A. bipustulata revealed its high potential as a predator, and a similar assay developed for two carabid beetle species showed these to be seldom if ever consumed. Laboratory and field cage assays with other CM egg predators showed A. bipustulata has potential to disrupt other species, particularly the closely related A. bilineata Gyllenhal, as they seem to forage in similar microhabitats. Measurements of field-collected beetles indicate CM is unlikely to be the primary host in Europe, so introducing A. bipustulata to Canada may bring risks to non-target Diptera species. This was observed even though a series of laboratory experiments demonstrated CM is a superior and preferred host relative to the smaller, acalyptrate cheese skipper.

Bulk density, angles of repose and coefficients of friction against four structural surfaces of two varieties of high oil content canola (Invigor 5440; oil content 47.1% ± 0.27%; and Nex4 105; oil content 45.4% ± 0.35%) and mixtures of them (with ratios of 1:1, 1:2 and 2:1) at four moisture contents (8%, 10%, 12% and 14%, wet basis) were determined. The same physical properties of one high oil content canola (45H29; oil content 45.4% ± 0.12%) and one low oil content canola (5525 Clearfield; oil content 42.4% ± 0.07%) at three moisture contents (8%, 10% and 12%) were determined. The coefficient of friction was measured against four structural surfaces: galvanized steel, plywood, and wood-floated and steel-trowelled concrete. Seed major and minor axes (dimension) of 45H29 canola at moisture contents of 8%, 10% and 12%, and Nex4 105, Invigor 5440 and 5525 Clearfield canola at 10% moisture content were measured. Major and minor axes of 45H29 increased with increases in moisture content. The oil content did not affect axes of canola seeds. Bulk densities were significantly different between Invigor 5440 and Nex4 105 canola. Bulk densities of mixtures of Invigor 5440 and Nex4 105 were higher than that of Nex4 105 and lower than that of Invigor 5440. Bulk density decreased with an increase in oil content. Angles of repose depended more on canola types and surface properties than oil content. Coefficient of friction against structural surfaces was not significantly affected by moisture content but was affected by oil content. Bins used to store low oil content canola could be used to store high oil content canola. Temperature and moisture content of stored crops affect safe storage time. The three high oil content canola varieties (45H29, Invigor 5440 and Nex4 105) and one low oil content canola variety (5525 Clearfield) with 8%, 10%, 12% and 14% initial moisture contents (wet basis) were stored at 10ºC, 20ºC, 30ºC and 40ºC for 20 wk. Moisture content, germination, fatty acid value (FAV) and visible and invisible mould of the canola seeds were determined every 2 or 4 wk. Increase of moisture content and temperature increased germination loss and mould infection. Fatty acid values of canola seeds at 10ºC, 20ºC and 30ºC increased with an increase of storage time; but at 40ºC, it increased at the beginning of storage, and then dramatically decreased. Storage fungi (Penicillium spp., Aspergillus glaucus group and Aspergillus candidus Link) were predominant throughout the study. Invisible mould and FAV were not suitable for predicting safe storage time of canola. Based on the 20% loss of initial germination, safe storage guidelines of high oil content canola were developed. To safely store high oil content canola, its moisture content should be lower than that of low oil content canola. The variety (Nex4 105) with 10% initial moisture content was stored in three large bins (2.74 m diameter; 5.03 m high) at simulated Western Canadian storage conditions (from September to December in the year 2010), to verify the developed safe storage guidelines of high oil content canola. The developed safe storage guidelines worked well in the real situation, except that hot spots in the grain bulk might cause dramatic increase of moisture content and temperature that can accelerate canola deterioration.

The exotic cabbage maggot (CM) infests canola on the prairies, feeding on roots in its larval stage, which disrupts the uptake of nutrients and water and provides an entry point for fungal plant pathogens. The European staphylinid, Aleochara bipustulata L., may be introduced for control of CM, but only if the risk to other species is low and if A. bipustulata has demonstrable potential to increase mortality already caused by natural enemies in Canada. Aleochara bipustulata could contribute to pest management as a predator of CM eggs and larvae, and as a parasitoid of CM puparia; however, it could affect non-pest species in the same two ways. A variety of invertebrates that share the soil of Brassica fields with immature CM were screened in laboratory no-choice assays to determine what adult A. bipustulata eat. In these assays, immobile or barely mobile invertebrates were accepted regularly and could be at risk. The majority of groups were seldom or never consumed. Also, a molecular assay developed to test for CM DNA in the guts of field-collected A. bipustulata revealed its high potential as a predator, and a similar assay developed for two carabid beetle species showed these to be seldom if ever consumed. Laboratory and field cage assays with other CM egg predators showed A. bipustulata has potential to disrupt other species, particularly the closely related A. bilineata Gyllenhal, as they seem to forage in similar microhabitats. Measurements of field-collected beetles indicate CM is unlikely to be the primary host in Europe, so introducing A. bipustulata to Canada may bring risks to non-target Diptera species. This was observed even though a series of laboratory experiments demonstrated CM is a superior and preferred host relative to the smaller, acalyptrate cheese skipper.

This project investigated the phenological development of canola through the 2009 growing season in the western Canadian prairies and quantified the effects of 624 weather parameters on nine canola quality parameters from 247 samples of Canada No. 1 canola. Predictive models were created to utilize as few of the most strongly correlated weather predictors as possible to explain a maximum amount of variation in each of the quality parameters. An intensive field study carried out at seven sites across Manitoba measured weather conditions and followed canola crop development from seeding through swathing, harvest or physiological maturity. These data were used to produce an index with six Physiological Day (P-Day) thresholds corresponding to specific growth stages. A comparison to the thresholds determined from a previous study suggested that current varieties require fewer heat units for early vegetative growth stages, more heat units during reproductive stages, and slightly greater P-Day accumulations to reach maturity. Canola samples from the field study were combined with western Canadian canola samples from collaborating companies and the 2008 and 2009 Canadian Grain Commission Harvest Surveys for quality analysis. The samples were analysed for oil content, protein content, oleic, linoleic, linolenic, and total saturated fatty acid contents and iodine value. Weather data from the intensive field study, collaborating companies, the Canadian Wheat Board and Environment Canada weather stations nearest each canola sample were compiled and arranged from the seeding to swathing date of each canola sample. These data were then used to calculate the accumulation of P-Day values from seeding until each of the six phenological growth stages. Partial Least Squares analysis was utilized to produce predictive models for each of the nine quality parameters. The results indicated that environmental parameters, especially temperature, had a significant impact on canola quality. The predictive models explained between 7 and 49% of the variation in individual quality parameters. The models for saturated fatty acids, glucosinolates and iodine value explained the highest amount of variation and the model for chlorophyll explained the least. Oil content was positively impacted by a longer duration of temperatures below 11-14oC throughout the reproductive stage, while protein was positively impacted by cool temperatures at early flowering and high temperatures throughout pod and seed development. Chlorophyll was strongly impacted by the moisture balance throughout early to mid reproductive stages and glucosinolates content was affected by conditions that impacted nutrient availability. Total saturated fatty acid content was positively impacted by cool temperatures throughout late vegetative and early reproductive stages. Moderate predictability of the individual fatty acid content models may have been indicative of either successful breeding of current canola varieties with relatively stable quality characteristics across a range of growing conditions or the complex interactions between oil content and the individual fatty acids measured. Producers looking to maximize canola quality and canola breeders interested in creating varieties more resistant to the specific weather conditions which impact canola quality could benefit from this study. Predictions of crop quality would also be an asset to those marketing Canadian canola as an export.

Thesis (Ph.D) -- University of Adelaide, Depts. of Plant Science and Crop Protection, 1998. / Thesis (Ph.D.)--University of Adelaide, Depts. of Plant Science and Crop Protection, 1999? Bibliographical references: leaves 112-125.

Thesis (M. Sc.(Agric.)(Plant Production)--University of Pretoria, 2004. / Includes summary. Includes bibliographical references.