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Seed loss in canola (Brassica napus, Brassica rapa and Brassica juncea) leads to considerable loss of revenue and dispersal of canola seeds into the soil seedbank. Once canola seeds enter the soil seedbank a portion can become secondarily dormant and persist for many years creating volunteer weed problems in following crops. Reducing canola seed loss and seedbank persistence can be an important strategy to reduce the incidence of volunteer weeds. The primary hypothesis of this research was that canola seedbank addition and dormancy induction in the seed are affected by genotype and harvest method. To test this hypothesis, three studies were conducted with the following objectives: i) to determine canola seedbank addition from windrowing and direct-harvesting operations on commercial farms in western Canada, ii) to determine agronomic- and harvest-related factors that may increase seed loss in canola, iii) to determine the effect of stage of crop maturity at harvest on potential to develop seed dormancy in canola, iv) to evaluate canola genotypes and harvest methods to reduce canola seedbank addition. A total of 66 canola fields were surveyed across Saskatchewan in 2010 and 2011. Shattered seeds from these fields were sampled within 3 weeks of harvest by using a vacuum cleaner. Agronomic- and harvest-related data were collected for each field using questionnaires. In a separate small plot study the effects of harvest methods (windrowing and direct-harvesting) and pod sealant products (Pod-Stik® and Pod Ceal DC®) on seed loss in five canola genotypes (InVigor5440, RR45H26, InVigor5020, RR4362, and CL8571) were evaluated in 2010 and 2011. In both years, 6 harvest samples were collected weekly from InVigor5440 and InVigor5020 genotypes starting at early stage of crop maturity until harvest to assess the effect of seed maturity on dormancy induction. On commercial farms, the average seedbank addition was 5,821 viable seeds m-2, which was equivalent to 7.3% of the total seed yield. There was no difference in the reported yield and seedbank addition between windrowed and direct-harvested canola on commercial farms. But in the small plot study, windrowing resulted in higher seedbank addition. Higher seedbank addition was observed when the yield of canola was higher and when producers had a larger area seeded to canola. The observed seedbank addition was also higher in Roundup Ready genotypes and when a conventional combine harvester was used to harvest canola. Little primary dormancy and low potential to secondary dormancy induction was observed in InVigor5440 and InVigor5020 seeds at an early stage of crop maturity. But at full maturity seeds of both genotypes had no primary dormancy but showed high potential for secondary dormancy induction. This indicates that windrowing the evaluated genotypes at early stage of crop maturity lowered the potential for secondary dormancy induction. There were appreciable differences in seedbank addition among the evaluated canola genotypes but pod sealant products did not affect seed yield and seed shatter in canola. The results of this study suggest that canola seedbank addition can be minimized by growing genotypes having reduced seed loss and with the adoption of direct-harvesting operations.

Microsite disturbances – including mounds created by burrowing mammals – increase local plant community diversity by supporting unique species assemblages. I investigated whether Richardson’s ground squirrel (Urocitellus richardsonii) mounds support unique plant assemblages within five Manitoba prairie pastures, and explored the factors contributing to the plant assemblages documented. Richardson’s ground squirrel mounds supported unique species assemblages relative to bare-ground disturbances with removal of vegetation but no soil disturbance. These detectable shifts in plant community structure on mounds appear to be attributable to mound-specific environmental conditions responsible for delaying vegetative recolonization and facilitating establishment of early-succession species. In contrast, seed bank distribution did not appear to influence species assemblages on mounds. Further investigation into site-specific changes in species distribution on Richardson’s ground squirrel mounds is needed to appreciate the role of these burrowing mammals in pastureland communities. / February 2017

Master of Science / Department of Agronomy / William T. Schapaugh / Recent results from a genetic gain study have illustrated the contribution of plant breeding to the improvement in seed yield of soybean (Glycine max (L.) Merr.). The objective of this research was to characterize the changes in several physiological parameters that have occurred in the released cultivars with improvement of seed yield. Sixty maturity group III and 54 maturity group IV cultivars, released from the 1920's through 2010, were evaluated in dryland and irrigated environments at Manhattan, KS in 2010 and 2011. Genotypes were planted in four-row plots, 3.4 m long, spaced 76 cm apart, arranged in a randomized complete block design with four replications. Genotypes were evaluated for canopy temperature, leaf chlorophyll content, pollen germination, leaf chlorophyll fluorescence, leaf antioxidants, and yield components. Canopy temperature measurements were captured between 1000h and 1400h using an infrared camera multiple times from R1 continuing through R6. Leaf chlorophyll content was measured using a SPAD meter several times from R1 through R6. In vitro pollen germination was measured using incubation temperatures of 28 and 34° C, beginning at late R1 through the end of flowering. Leaf chlorophyll fluorescence was measured beginning at R1 through R6. Leaf antioxidants were analyzed for total antioxidant capacity and electrolyte leakage by collecting leaves from the top 3rd to 5th trifoliate at R4 and R6. Yield components were analyzed from a hand harvested 0.33 m section of one border row. Genotypes differed significantly for canopy temperature, leaf chlorophyll content, pollen germination, and yield components. No significant differences were found for leaf chlorophyll fluorescence or leaf antioxidants. Seed yield increased with year of release. Canopy temperature was negatively correlated and leaf chlorophyll content was positively correlated with year of release in both maturity groups. No significant correlation with year of release was found for in vitro pollen germination or electrolyte leakage. Leaf chlorophyll fluorescence, yield components, and total antioxidant capacity was positively correlated in the maturity group IV genotypes with year of release. Evaluation of these parameters may serve as a basis to select for seed yield, or to assess the abiotic stress tolerance of a genotype.

Master of Agribusiness / Department of Agricultural Economics / John Crespi / Hybrid seed corn pricing has increased significantly over the past six or seven years and continues to be a topic of conversation amongst farmers. This issue is also an area of concern for Monsanto. The hybrid corn pricing team at Monsanto is concerned that they price current products at a point to maximize profits while continuing to grow market share. The key is to price at a point that captures all the value of the differentiated products Monsanto offers. The objective for this study is to estimate a demand model for the hybrid seed corn industry. The demand model will allow us to look at many different aspects of the hybrid seed corn industry and also evaluate the own-price and cross-price elasticities. The own-price elasticity is especially important because it will be used to determine if current pricing is revenue or profit-maximizing. A hedonic pricing model was also estimated in this study to complement the demand model. It is important for Monsanto to understand what attributes or traits are significant in pricing and demand.

MSc., Faculty of Science, University of the Witwatersrand, 2011 / ABSTRACT Observations of the changes in woody plant density in the Kruger National Park (KNP) over 58 years have shown an increase in large woody plant density on granite substrates, which is attributed to fire and herbivore density. Woody plants persist in areas with frequent fires, herbivory and drought by resprouting or protecting seeds in the ground. Soil seed banks, which are stores of seeds below ground or in leaf litter, provide 'insurance' for trees and allow populations to persist in unfavourable environments. No comprehensive studies have been conducted on soil seed bank ecology of Acacia species in the Kruger National Park, a research gap which this study aimed to fill. The spatial distribution and density of in situ soil seed banks for four Acacia species, A. grandicornuta, A. nilotica, A. senegal and A. tortilis was assessed in the Skukuza land system of the KNP, South Africa. In situ soil seed banks were quantified for eight mature trees per species during 2005/2006. Greenhouse and field seed burial trials were carried out for one year and 16 months respectively, between 2005 and 2007, to investigate the persistence of Acacia seeds over an extended period of time. Post-dispersal seed predation of Acacia seeds was investigated during July 2006 in six demarcated grids within 15 km of Skukuza. Overall soil seed bank density differed significantly among species, being highest for A. tortilis (19.5 ± 6.4 seeds m-2), followed by A. grandicornuta (12.1 ± 6.9 seeds m-2), A. nilotica (4.9 ±1.8 seeds m-2) and lowest for A. senegal (0.6 seeds ± 0.4 seeds m-2). Generally, seed bank density decreased with depth in the soil and distance from the centre of the tree canopy. Seed bank density increased significantly with a decrease in soil compaction for A. senegal only, while it was not related to over-storey canopy shading or herbaceous biomass for any of the species. No significant relationship was found between seed bank density and tree characteristics such as stem diameter, bark thickness or tree canopy area for any of the species. Viability of seeds from the seed bank decreased between species as follows: A. tortilis (77% of 142 seeds), A. nilotica (61% of 39 seeds), A. grandicornuta (58% of 87 seeds), and A. senegal (0% of 4 seeds). For all species with viable seeds, viability decreased with distance from the centre of the tree canopy. Bruchid beetle predation (assessed on 100 newly produced seeds) was low for all four species. Fifty seeds each of A. grandicornuta, A. senegal and A. tortilis and 100 A. nilotica seeds were destroyed by fire during the field seed burial trial, of which four hundred seeds/species were used. Of the remaining seeds, 15% of A. senegal, 19% of A. grandicornuta, 34% of A. nilotica and 66% of A. tortilis remained intact after 16 months in the field. Of these, 65% of A. tortilis, 27% of A. nilotica, 5% of A. grandicornuta and no A. senegal seeds were still viable. The percentage of remaining intact, viable seeds was highest under tree canopy cover and buried for A. tortilis (86%), A. nilotica (39%) and A. grandicornuta (6%), but the micro-site placement of seeds had a significant effect on viability for A. nilotica only (d.f. = l; χ2 = 7.5; P = 0.006). In the greenhouse seed burial trial (150 seeds/species/treatment), one percent of the total seed lot germinated, which was 2.9% of A. grandicornuta, 0.7% of A. senegal and 0.2% of both A. nilotica and A. tortilis. A. tortilis had the highest percentage of remaining intact, viable seeds (92.2%), followed by A. nilotica (58.3%), A. grandicornuta (57.6%) and A. senegal (0%). The number of remaining intact, viable seeds was highest when watered with the average rainfall (327 seeds), followed by the highest (314 seeds) and lowest rainfall (296 seeds). There was no association between rainfall treatments and the number of remaining intact, viable seeds for any of the species, except for A. grandicornuta where the number of remaining intact, viable seeds increased significantly with the average rainfall. Across six grids in the Skukuza land system, A. grandicornuta was the most dominant woody plant of six study species, followed by Dichrostachys cinerea, A. tortilis, A. nilotica, A. senegal and A. nigrescens. Woody plant density in grids varied between 226 plants ha-1 (Grid 3) to 1618 plants ha-1 (Grid 5), with a mean density of 862 ± 195 plants ha-1. Overall, woody plant species diversity was low (Shannon Wiener Index, 1.8 ± 2.8; Evenness Index, 0.7 ± 0.02; Simpson's Reciprocal Index, 4.5 ± 0.6). The dung of nine species of large herbivore was recorded across all six grids. Large herbivores favoured seeds of indehiscent (55 A. tortilis seeds and 11 A. nilotica seeds) over dehiscent pods (1 A. grandicornuta seed). Only 9% (five A. tortilis seeds and one A. grandicornuta seed) of the 67 seeds extracted from dung germinated after a six-week germination trial. Less than half the remaining ungerminated A. nilotica seeds (46%) and A. tortilis seeds (40%) tested viable. There was no correlation between the number of termitaria recorded and the number of Acacia trees growing on them (r = 0.07). Termite mounds occupied 0.0009 ± 0.0003 ha per grid matrix (0.8%). Only four rodent species were recorded across all six grids, Mastomys coucha (multimammate mouse), Rhabdomys pumilio (striped mouse), Aethomys chrysophilus (red veld rat) and Tatera leucogaster (highveld gerbil). Rodent species diversity was low (Shannon Wiener Index, 0.6 ± 0.2; Evenness Index, 0.6 ± 0.2; Simpson's Reciprocal Index, 1.9 ± 0.3). In the field cafeteria trial there was a significant difference in the percentage of seeds removed between seed species (P < 0.05; F = 2.8; d.f. = 3, 236). There was a significant difference in the percentage of seeds removed from trays placed under vegetation cover compared with trays placed in the open (P = 0.034). This study suggests that A. grandicornuta, A. nilotica and A. tortilis seeds form short-term persistent seed banks, while A. senegal seeds are transient and do not form seed banks. Seeds of several woody plants were ingested by large herbivores and selected by rodents. The relevance of soil seed banks to regeneration of Acacia trees needs to be evaluated by investigating whether these species rely more on seed production or resprouting for individual recruitment into tree populations. Once this issue is clarified the effect of certain factors on seed fate and consequently, recruitment of individuals into plant populations, can be more clearly understood. This will assist in managing and understanding these potentially encroaching species in the Kruger National Park, South Africa.

The limited specificity, sensitivity and multiplex capacity of detection techniques currently available for important seed-borne pathogens of tomato is a significant risk for the global tomato trade and production industry. These pathogens can be associated with seed at low concentrations but, due to their highly virulent nature, these low levels can be sufficient to infect germinating seedlings and spread to neighbouring plants and fields, potentially causing epidemics and economic losses. In this study, detection techniques currently available for phytodiagnostics were evaluated for the capacity to accurately detect and identify five agronomically important seed-borne pathogens of tomato: Pepino mosaic virus (PepMV), Tomato mosaic virus (ToMV), Clavibacter michiganensis subsp. michiganensis (Cmm), Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato. A prototype diagnostic microarray was also designed in an attempt to develop a tool that could simultaneously detect these five seed-borne pathogens from a single sample. Viral detection based on serological techniques was rapid, accurate and reliable but only detected a single pathogen per assay and required supplementary bioassays to indicate the viability of detected viral pathogens. Selective media plating for bacterial detection demonstrated unreliable recovery of targeted bacteria from infected seed and leaf samples and required supplementary tests to validate the identity of presumptive positives. Assays were lengthy, laborious and sometimes too ambiguous for accurate diagnosis of bacterial pathogens. Nucleic acid-based technologies demonstrated improved sensitivity and specificity for detection of targets from pure culture, leaf and seed extracts, compared to conventional and serological methods, yet also required supplementary bioassays or media assays to validate the viability of detected pathogens. Amplification efficiency however, was affected by the presence of PCR inhibitors and despite positive detection, variable banding intensity in electrophoretic analysis of amplified products necessitated the use of reference cultures to validate diagnosis. The developed microarray incorporated 152 pathogen-specific and control probes to facilitate diagnosis and taxonomic classification of detected pathogens. The array was challenged with pure culture extracts of the five target pathogens, selected related and non-target, unrelated pathogens of tomato. Positive detection of each of the pathogens was demonstrated but the production of hybridisation signals was highly variable and extremely sensitive to minor technical differences. Each of the five pathogens were successfully detected in combination proving that different classes of seed-borne pathogens could be detected from a single sample using the developed microarray. This prototype microarray has good potential for phytodiagnostic screening of the five targeted pathogens, and further validation, optimisation and extension for testing tomato seed samples may facilitate incorporation of this array into standard diagnostic protocols.

Gopher tortoises (Gopherus polyphemus) are keystone species mainly due to their burrow construction. Gopher tortoises can also impact the plants around them, but it is rarely quantifiable due to constraints in dispersal studies including time period and seasonality of fruit. The objective of this study was to measure the effect gut-passage has on a native Florida stone-pitted shrub, the cocoplum bush (Chrysobalanus icaco), as well as to attempt to model the relationship between the gopher tortoise and the plant using our unique field site. This study shows that gut-passage has a significant effect on the germination rate of the cocoplum, allowing it to germinate faster than control groups. This study also found that a model involving covariates relating to tortoise movement as a predictor for cocoplum intensity was favored over a homogeneous null model. We believe the pattern of plants is nonrandom and relates to the gopher tortoise’s seed dispersal. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Thesis (MTech (Food Technology))--Cape Peninsula University of Technology, 2018. / The use of egusi melon in soup has been domesticated and egusi has predominantly been regarded as a secondary crop. The aim of this study was to evaluate the functional characteristics of egusi seed (Citrullus lanatus subsp mucosospermus) hydrocolloid and oil in instant egusi soup. An instant production of egusi soup by adding boiling water to an instant soup mix will promote the availability of this nutritious seed as a healthy meal option. Egusi oil was successfully extracted from egusi seed using supercritical carbon dioxide method. The percentage oil yield which measures the amount of oil derivable from egusi seed ranged from 46-53% w/w. There was a significant difference in the oil yield as pressure and temperature are increased at a constant CO2 flow rate of 30 g/h. The proximate composition of egusi oil was determined using standard AOAC method. The moisture contents were 1.3, 2.0 and 1.9% w/w, respectively for EO1 (60oC and 450 bar), EO2 (55oC and 600 bar) and EO3 (75oC and 600 bar). EO1 was significantly (p ≤ 0.05) lower in moisture content compared to EO2 and EO3. The fat content was 99.1% w/w (EO1), 98.3% w/w (EO2) and 98.9% w/w (EO3), with no significant difference in the three oil samples. The fatty acid composition was analyzed using gas chromatography. The fatty acid content of egusi oil was high in polyunsaturated and monounsaturated fatty acids, which was identified as linoleic (62%) and oleic (15%) acids. The saturated fatty acid (undecylic, myristic, palmitic and stearic) composition of egusi oil differed significantly (p ≤ 0.05) with EO1, having the lowest compared to EO2 and EO3. The index of atherogenicity (IA %) were significantly low 0.35, 0.38 and 0.38% w/w for EO1, EO2, and EO3, respectively. The thrombogenicity index (IT %) were 0.08, 0.09 and 0.09% w/w for EO1, EO2, and EO3, respectively with no significant difference. Peroxide Value (PV) measured using auto titrate Titrino plus, ranging from 11.60 for EO1 milliequivalents peroxide/kg to 12.60 for EO2 and 11.89 milliequivalents peroxide/kg for EO3. The oxidative stability index (OSI) was measured using Methrohm Rancimat at 120°C, expressed as the induction time of oxidation was 10.2, 11.5 and 5.3 h for EO1, EO2, and EO3, respectively, with E03 significantly higher than EO1 and EO2 (p ≤ 0.05). The iodine number, determined by AOAC direct titration method was high and ranged from 95 g/100 g for EO1 to 129 g/100 g for EO3, with EO3 being significantly high (p ≤ 0.05). The nutritional and functional properties of defatted egusi flour and hydrocolloid extracted using supercritical carbon dioxide extraction was also successfully achieved. Proximate analysis of defatted egusi (DEF) flour after supercritical extraction was carried out according to standard AOAC procedures. The moisture content of DEF ranged from 5.3 to 10.1% w/w, crude protein 48.3 to 60.4% w/w, crude fibre 3.4 to 4.5% w/w) and ash 5.3 to 6.8 % w/w). The protein content of defatted egusi flour differed significantly (p ≤ 0.05) between samples. The amino acid compositions of DEF showed glutamic acid had the highest concentration of 12.9, 11.8 and 9.8 mg/100 g for DEF1, DEF2, and DEF3, respectively with a significant difference (p ≤ 0.05) across the samples. In functionality, the water absorption and solubility index at a low temperature of 50oC ranged between 52.5 to 57.6% w/w and 68.0 to 73.3% w/w respectively for DEF1 to DEF3, which significantly differed between samples. The final viscosity of defatted egusi flour ranged from 126.7 to 126.3 cP, which differed significantly (p ≤ 0.05) between samples. Egusi flour is high in protein 60% w/w and carbohydrate 25% w/w was treated with hot water to extract its hydrocolloid. Functional properties of egusi hydrocolloid for the three defatted flour shows a stable emulsifier as the breakdown viscosity remained constant at (8.00 cP). Breakdown viscosity of egusi hydrocolloid confirmed its stability.

by Foo Wai Ting, Rita. / Thesis submitted in: August 1998. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 89-100). / Abstract also in Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Proximate Composition --- p.4 / Chapter 1.2 --- Amino Acid Composition --- p.6 / Chapter 1.3 --- Antinutrients --- p.11 / Chapter 1.3.1 --- Trypsin Inhibitors --- p.12 / Chapter 1.3.2 --- Phytate --- p.13 / Chapter 1.3.3 --- Tannins --- p.14 / Chapter 1.3.4 --- Lectins --- p.15 / Chapter 1.4 --- Two Dimensional Polyacrylamide Gel Electrophoresis --- p.17 / Chapter 1.5 --- Protein Digestibility --- p.19 / Chapter 1.6 --- Protein Quality --- p.22 / Chapter 1.7 --- Hypocholesterolemic Effects --- p.24 / Chapter 2 --- Materials and Methods --- p.36 / Chapter 2.1 --- Plant Material --- p.36 / Chapter 2.2 --- Sample preparation --- p.36 / Chapter 2.3 --- Proximate composition --- p.38 / Chapter 2.3.1 --- Protein --- p.38 / Chapter 2.3.2 --- Fat --- p.38 / Chapter 2.3.3 --- Carbohydrate --- p.38 / Chapter 2.3.4 --- Fiber --- p.38 / Chapter 2.3.5 --- Mineral --- p.39 / Chapter 2.3.6 --- Moisture --- p.39 / Chapter 2.4 --- Amino acid composition --- p.40 / Chapter 2.5 --- Antinutrients --- p.41 / Chapter 2.5.1 --- Trypsin inhibitors --- p.41 / Chapter 2.5.2 --- Tannins --- p.42 / Chapter 2.5.3 --- Phytate --- p.43 / Chapter 2.5.4 --- Lectins --- p.43 / Chapter 2.6 --- Two dimensional polyacrylamide gel electrophoresis --- p.45 / Chapter 2.6.1 --- Protein extraction --- p.45 / Chapter 2.6.2 --- IEF gel --- p.45 / Chapter 2.6.3 --- SDS gel --- p.46 / Chapter 2.7 --- Protein digestibility --- p.48 / Chapter 2.7.1 --- In vitro Protein digestibility --- p.48 / Chapter 2.7.2 --- True Protein digestibility --- p.49 / Chapter 2.8 --- Protein quality --- p.51 / Chapter 2.9 --- Hypocholesterolemic effects --- p.52 / Chapter 2.10 --- Statistical analysis --- p.55 / Chapter 3 --- Results --- p.56 / Chapter 3.1 --- Proximate composition --- p.56 / Chapter 3.2 --- Amino acid composition --- p.56 / Chapter 3.3 --- Antinutrients --- p.56 / Chapter 3.4 --- Two dimensional polyacrylamide gel electrophoresis --- p.60 / Chapter 3.5 --- Protein digestibility --- p.60 / Chapter 3.6 --- Protein quality --- p.60 / Chapter 3.7 --- Hypocholesterolemic effects --- p.62 / Chapter 3.7.1 --- Growth rate against day --- p.62 / Chapter 3.7.2 --- Health indexes --- p.64 / Chapter 3.7.3 --- Cholesterol content --- p.64 / Chapter 4 --- Discussion --- p.67 / Chapter 4.1 --- Proximate composition --- p.67 / Chapter 4.2 --- Amino acid composition --- p.70 / Chapter 4.3 --- Antinutrients --- p.74 / Chapter 4.4 --- Two dimensional polyacrylamide gel electrophoresis --- p.77 / Chapter 4.5 --- Protein digestibility --- p.79 / Chapter 4.6 --- Protein quality --- p.81 / Chapter 4.7 --- Hypocholesterolemic effects --- p.82 / Chapter 5 --- Conclusion --- p.88 / References --- p.89