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Thesis (M.Sc. (Horticulture)) -- University of Limpopo, 2022 / The awareness of the nutritional benefit and consumption of the Jew’s mallow (Corchorus olitorius L.) especially in South Africa is low; this is predominantly because of lack of access and availability of the crop in the market. This research aimed to determine to what extent would the planting period affect mucilage, growth, yield and nutritional composition of the selected C. olitorius cultivar under different growing conditions and provide a better understanding and scientific evidence for the producers to maximize production. The experiments were carried out simultaneously, the first experiment (field trial), was on the field and the second (pot trial) in the shade house. Treatment factors were: 2 x growing conditions (field and pot), 4 x planting periods (November, December, January and February) and 3 x C. olitorius cultivars (‘Local’, ‘Oniyaya’ and ‘Amugbadu’). The experiments were carried out as randomised complete block design (RCBD) arranged in split-spilt plot with three replications. Growing condition was the main factor, planting period as the sub-factor, while the cultivars were the sub-subplot factor. Mucilage content, growth and yield parameters were measured and nutritional composition of the crop was determined from harvested plant samples. Mucilage content of C. olitorius varied with cultivar and growing condition. The significantly (P < 0.05) highest quantity of mucilage at 8 WAT was obtained from Oniyaya cultivar under field condition whereas the least was recorded from Local cultivar under pot condition. The mucilage content of the three cultivars did not differ significantly (P ≤ 0.05) at 6 WAT, however significant (P < 0.01) differences were recorded at 8 WAT. The cultivar Oniyaya produced significantly highest average (184.58 mPa.s) mucilage content at 8 WAT while the lowest average value (124.58 mPa.s) was recorded in the Local cultivar. This implies that Oniyaya cultivar produced the slimiest plants. The mucilage content of Jew’s mallow appears to decline over time; thus, the crop had higher mucilage content when young and tender. Selected growth parameters such as chlorophyll, number of leaves and stem diameter were significantly affected by the combined effect of cultivar, planting period and growing condition. For example, the average highest chlorophyll content was obtained in Oniyaya cultivar during November period under pot conditions. While the greatest number of leaves at 8 WAT were obtained in Oniyaya and Local cultivars during xxvii December planting period and in Amugbadu during November period all under the field conditions. All cultivars grown during the February planting period had the lowest average number of leaves. Growth parameters such as number of branches, plant height and leaf area were not significantly (P ≤ 0.05) affected by the combined effect of cultivar, planting period and growing condition. Significant (P < 0.05) combined effect of cultivar and planting period was recorded on number of C. olitorius branches at 6 WAT. Furthermore, significant interaction between planting period and growing condition was also recorded. The significantly higher number of branches at 6 WAT was obtained from Oniyaya and Amugbadu cultivars during the November planting period. The test crop seedlings transplanted in February had the lowest average number of branches. Comparing the cultivars at 6 and 8 WAT, Oniyaya produced significantly (P < 0.01) higher number of branches than Local. Local cultivar was significantly taller than others under the field condition; while significantly tallest plant was obtained during December period under the same condition. The differences observed in C. olitorius shoot and root fresh and dry masses were not significantly different in their responses in relation to the combined effect of cultivar, planting period and growing condition. However, the significantly highest average fresh shoot mass was obtained during December period and the lowest average values in February planting period. The combined effect of cultivar, planting date and growing condition had significant (P < 0.01) influence on number of days to 50% flowering; pod formation and pod maturity of C. olitorius. The significantly longest average number of days to 50% flowering was observed in Oniyaya and Amugbadu cultivars during November period under field condition, while Local cultivar flowered at the shortest period, but produced highest number of pods and seed yield during the December planting period under the same condition. Cultivar, planting date and growing condition had significant (P < 0.01) influence on Zinc contents of C. olitorius. Whereas the three factors had no significant effect on N, Ca, Mg, K, Na, Mn, Fe, P, Al, ash and dry matter contents of the crop. The highest average amounts of N, Mg and K were obtained from Local cultivar during November period while the same cultivar produced the highest average amount of Ca during December period. In conclusion, the mucilage content and fresh shoot mass (which is xxviii the marketable part of C. olitorius) were optimal in crops grown during the December planting period when the temperatures are at the highest. While better nutritional content of the crop was better attained during the November planting period. Both November and December planting periods allowed C. olitorius to reach its maximum growth capacity, translating to higher yielding parameters than other planting periods.

Rice is a staple crop for many countries around the world, and is one of the top three food sources globally. Many environments where rice is grown contain stressors likely to limit its growth and yield. In southern Senegal (Casamance region), rice is mainly cultivated in lowlands near estuaries where drought, salinity, acidity, poor soil fertility, and iron toxicity are the main limiting factors. In Casamance, average rice yield for local farmers is 1 to 2 tons per hectare (809 to 1618 pounds per acre), compared to worldwide average yield of more than 4 tons per hectare. The soil where our 2-year experiment (2014 and 2015) was conducted is highly saline-sodic and acidic, and the salt tolerant cultivar we grew yielded 3.4 tons per hectare in 2013. Our main objective was to increase rice yield. The water table height, salinity, and pH were measured weekly during the rice growing season, and the soil was described, sampled, and analyzed to better understand the water and soil resources. Two planting methods were tested: flat planting and planting on beds. Two soil amendments were compared with each planting method: biochar and crushed oyster shells, alone and in combination. An untreated control was included in the experiment. All plots were fertilized. Treatment effects on soil properties and yield were compared in a split-plot design. Plant tissue was sampled for elemental content. The water table was above the surface and was saline during half of the growing season in 2014, and decreased after rice grain head emerged. Planting methods and amendments did not have an effect on yield in 2014, but biochar amendment increased yield in 2015. In 2014, soil salinity and sodium decreased to below toxic levels late in the growing season in the flat plots but not in the bedded plots. Therefore, flat planting is more appropriate in these lowland rice production systems. Soil pH increased from 4.4 to 7.7 in flat planting where biochar+shell was applied. Soil available nutrients such as P, Mn, and Zn were significantly higher in flat planting compared to beds. Toxic levels of Na (> 2000 milligrams per kilogram) were measured in leaves sampled just before flowering. We recommend flat planting and amending soil with biochar in saline-sodic acid-sulfate paddy soils in Casamance to improve rice yield. / Master of Science

In the United States, hops (Humulus lupulus L.) are grown mainly in the Pacific Northwest (PNW). For this reason, most cultural information is based on the growing conditions of the PNW. Growing conditions in Virginia differ drastically and present unique disease and production challenges. Three studies were conducted with the intent of increasing hop cultivation knowledge for Virginia growers. For the first study, 13 cultivars of hops grown at the Virginia Tech hop yard were compared for growth, yield, and quality. Mean cone fresh weight per plant ranged from 12.00 g for Mt. Hood to 1002.87 g for Crystal in 2016 and from 97.98 g for Mt. Hood to 900.33 g for Cascade in 2017. In 2016, only Alpharoma, Cascade, Mt. Rainier, and Southern Cross had alpha acid levels, an indicator of cone quality, within the accepted range. In 2017, Alpharoma, Centennial, Mt. Rainier, and Nugget had alpha acid levels within the expected range. Three cultivars (Cascade, Crystal, and Ultra) were above the expected alpha acid range, which indicates more bittering potential for beer brewers. In a nutrient deficiency study, hop plants were grown in hydroponic solutions, and deficiencies were induced for nitrogen (N), phosphorus (P), and potassium (K). After visual deficiency symptoms had been induced, leaf tissue samples were taken and analyzed for nutrient content. Images were taken at each deficiency stage. For N, incipient deficiency symptoms were observed at a mean of 3.18% dry weight in leaf tissue samples. Visual symptoms included a chlorotic appearance, undersized leaves, and red petioles. Incipient symptoms for P were observed at a mean of 0.307% dry weight in leaf tissue samples. Necrotic spots, leaf cupping, and undersized leaves were apparent with this deficiency. Incipient symptoms for K were observed at a mean of 1.21% dry weight in leaf tissue samples. Symptoms included rounded leaf tips, blue veins, and marginal scorch. In the third study, a whole leaf powdery mildew (Podosphaera macularis) assay was developed and tested using five hop cultivars, Alpharoma, Cascade, Comet, Sorachi Ace, and Tahoma. Leaves were inoculated with powdery mildew (PM) using a settling tower. This method was used to rapidly assess the resistance of cultivars. Leaves were successfully inoculated and PM colonies were allowed to grow for two weeks. Images of the PM colony development on inoculated leaves were compared using ImageJ to determine percentage of coverage. Tahoma was the only cultivar found to produce a significantly different mean percent coverage (19.5%) compared with the resistant cultivars Cascade and Comet (<1%). / Master of Science in Life Sciences / Hops (Humulus lupulus) were first grown in the United States in Massachusetts in the early 1600s. Production of this crop eventually spread throughout the Northeastern US. By the mid-1800s, commercial production spread to southern states such as Virginia. Infestation of pests, e.g., hop aphid and diseases such as downy mildew in eastern states, and prohibition on the production of alcohol caused a significant shift in hop production, which favored the Pacific Northwest (PNW). As a result, in Virginia specific knowledge of hop cultivation is now lacking. Three studies were conducted to increase our knowledge of hop cultivation for the region. For the first study, 13 cultivars grown at the Virginia Tech hop yard were compared for growth, yield, and quality. The cultivars Cascade and Alpharoma had alpha acid levels equal to or higher than expected for the 2016 and 2017 seasons. The alpha acid levels are an indicator of the hop quality from the Cascade and Alpharoma cultivars. Cascade was also a top producer of hop cones with a mean fresh weight of 989.67 g and 900.33 g in 2016 and 2017, respectively. In a nutrient deficiency study, plants were grown in Hoagland hydroponic solutions, which contain all essential nutrients needed for plant growth. This was done to provide photographic documentation to assist local growers with deficiency identification. Deficiencies were induced for nitrogen (N), phosphorus (P), and potassium (K) by removing each of the specific nutrient of interest from each treatment solution. After deficiency symptoms were induced, leaf tissue samples were taken and analyzed for nutrient content. Nutrient deficiencies were documented using photographs. For N, visual symptoms included a chlorotic appearance, undersized leaves, and red petioles. Incipient symptoms for P included necrotic spots, leaf cupping, and undersized leaves. For K, leaf cupping, blue green veins, marginal scorch, and rounded leaf tips. Disease resistance of cultivars is important information for growers and can heavily influence hop yard planning. As such, in another study, an assay for powdery mildew (Podosphaera macularis) was developed that allows for rapid low cost testing of hop cultivars. The assay was tested on the following cultivars: Alpharoma, Cascade, Comet, Sorachi Ace, and Tahoma. Leaves were inoculated with powdery mildew (PM) using a settling tower. Powdery mildew colonies were allowed to grow for two weeks and were then analyzed using ImageJ software to determine percent coverage. At the end of the experiment, Tahoma had significantly greater PM coverage compared to the other cultivars, indicating that Tahoma is less resistant to the specific PM strain. / Hops (Humulus lupulus) were first grown in the United States in Massachusetts in the early 1600s. Production of this crop eventually spread throughout the Northeastern US. By the mid-1800s, commercial production spread to southern states such as Virginia. Infestation of pests, e.g., hop aphid and diseases such as downy mildew in eastern states, and prohibition on the production of alcohol caused a significant shift in hop production, which favored the Pacific Northwest (PNW). As a result, in Virginia specific knowledge of hop cultivation is now lacking. Three studies were conducted to increase our knowledge of hop cultivation for the region. For the first study, 13 cultivars grown at the Virginia Tech hop yard were compared for growth, yield, and quality. The cultivars Cascade and Alpharoma had alpha acid levels equal to or higher than expected for the 2016 and 2017 seasons. The alpha acid levels are an indicator of the hop quality from the Cascade and Alpharoma cultivars. Cascade was also a top producer of hop cones with a mean fresh weight of 989.67 g and 900.33 g in 2016 and 2017, respectively. In a nutrient deficiency study, plants were grown in Hoagland hydroponic solutions, which contain all essential nutrients needed for plant growth. This was done to provide photographic documentation to assist local growers with deficiency identification. Deficiencies were induced for nitrogen (N), phosphorus (P), and potassium (K) by removing each of the specific nutrient of interest from each treatment solution. After deficiency symptoms were induced, leaf tissue samples were taken and analyzed for nutrient content. Nutrient deficiencies were documented using photographs. For N, visual symptoms included a chlorotic appearance, undersized leaves, and red petioles. Incipient symptoms for P included necrotic spots, leaf cupping, and undersized leaves. For K, leaf cupping, blue green veins, marginal scorch, and rounded leaf tips. Disease resistance of cultivars is important information for growers and can heavily influence hop yard planning. As such, in another study, an assay for powdery mildew (Podosphaera macularis) was developed that allows for rapid low cost testing of hop cultivars. The assay was tested on the following cultivars: Alpharoma, Cascade, Comet, Sorachi Ace, and Tahoma. Leaves were inoculated with powdery mildew (PM) using a settling tower. Powdery mildew colonies were allowed to grow for two weeks and were then analyzed using ImageJ software to determine percent coverage. At the end of the experiment, Tahoma had significantly greater PM coverage compared to the other cultivars, indicating that Tahoma is less resistant to the specific PM strain.

Cotton (Gossypium hirsutum L.) growth and development, lint yield, and fiber quality are influenced by many management decisions. Three field experiments examining the interaction of plant population and planting date, and cultivar or herbicide and plant growth regulator application on these parameters were conducted in Virginia during 2005 and 2006 and in North Carolina, South Carolina, and Louisiana during specific years. Experiment I: Plant Population and Planting Date Lint yields were highest with populations of 8.9 and 12.8 plants m¯² compared to 5.3 plants m¯² in Virginia and North Carolina, while in Louisiana the highest yields resulted from populations of 5.8 and 9.5 plants m¯² compared to 17.1 plants m¯². Earlier planted (1 May) cotton produced higher yields relative to later planted (21 May) cotton in Louisiana, while yield was not influenced by planting date in Virginia and North Carolina. The impact of plant population and planting date on cotton appeared to be influenced significantly by heat unit accumulation. Experiment II: Cultivar and Mepiquat Pentaborate Application Mepiquat pentaborate (MPB) application consistently decreased plant height, HNR, and enhanced maturity for all cultivars, compared to untreated cotton. A trend of decreasing yield with increasing MPB application in Virginia was observed. These data suggests that cotton response to MPB application is influenced by cultivar maturity or fruiting interval. Experiment III: Trifloxysulfuron-sodium and Mepiquat Chloride Application Trifloxysulfuron-sodium (TFS) did not influence vegetative growth, maturity, or yield in comparison to untreated cotton. Mepiquat chloride (MC) application reduced vegetative growth and enhanced maturity in most years. The results of this experiment demonstrate that TFS application does not have the same effects on plant growth as MC application. / Master of Science

Field experiments (2007-2009) and laboratory bioassays (2009) tested the efficacy of insecticides with short pre-harvest intervals, caneberry cultivar susceptibility, and geranium toxicity for reducing Japanese beetle (JB) activity on primocane-bearing caneberries. Deltamethrin, chlorantraniliprole, bifenthrin, lime-alum, and thyme oil reduced JB activity in the field. Deltamethrin, chlorantraniliprole, acetamiprid, an azadirachtin and pyrethrin mixture, an azadirachtin and neem oil extract mixture, and an extract of Chenopodium ambrosioides reduced JB activity during the bioassays. "Prelude" had significantly more JB than "Anne", "Caroline", "Heritage", "Dinkum", or "Himbo Top" and "Prime-Jan" had significantly more JB than "Prime-Jim". Compared to certain cultivars, "Heritage", "Caroline", "Himbo Top", and "Prime-Jan" had higher percentages of injured fruit and "Autumn Bliss", "Heritage", and "Caroline" produced greater marketable and overall yields. "Prime-Jan" produced more overall yield than "Prime-Jim"; marketable yields from both blackberry cultivars were similar. Defoliation was significantly less for "Dinkum", "Caroline", "Heritage", and "Anne" than for "Prelude" in 2008 and significantly less for "Caroline" and "Anne" than "Prelude" or "Fall Gold" in 2009. In field tests, previous consumption of geraniums lessened raspberry defoliation by JB. Bioassays indicated that JB activity was only reduced if JB were continually exposed to geranium. Therefore, the efficacy of geranium as a trap crop for JB may be limited. The stink bug species within the caneberries were identified (2008-2009) and Euschistus servus (Say) made up 48.1 % of the overall species composition. Stink bug injury to ripening raspberries was identified as small holes between drupelets; stink bug excretions also ruined fruit. / Master of Science in Life Sciences

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21835号 / 農博第2348号 / 新制||農||1068(附属図書館) / 学位論文||H31||N5207(農学部図書室) / 京都大学大学院農学研究科農学専攻 / (主査)教授 白岩 立彦, 教授 稲村 達也, 准教授 田中 朋之 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

The ability to identify germplasm and select traits accurately is fundamental to successful plant breeding. Pedigrees and molecular markers facilitate these processes; however misleading experimental results can occur when incorrect relationships and/or cultivar names are recorded. Molecular markers can identify these inconsistencies, and with advances in genotyping technology these diagnostics can be done faster and more objectively. This study aimed to develop molecular marker assays and graphical genotyping methodologies for cultivar identification, seed purity assessment and trait selection in oat (Avena sativa L.). KBioscience’s Allele-Specific PCR (KASP™) and genotyping-by-sequencing (GBS) technologies were applied to a set of current Canadian oat cultivars to evaluate their utility for identifying cultivars and detecting intra-cultivar variation. Both KASP™ and GBS detected different extents of heterogeneity among a set of 160 seeds that originated from four seed sources of four cultivars. In both cases, the detected variation did not appear to be limited to a specific cultivar or seed source, reinforcing that all cultivars are heterogeneous. Graphical genotyping localized heterogeneity to specific chromosome regions, thereby distinguishing physical contamination from true genetic heterogeneity and heterozygosity. Pre-existing genotype data for 700 oat cultivars and breeding lines were also used to construct graphical genotypes for pedigree validation and discovery of potential sources for favourable quantitative trait loci (QTL) alleles. This methodology used historical QTLs and anchoring markers to identify 25 putative “high oil” allele carriers. The results from this study will provide diagnostic tools for cultivar identification and pedigree validation, in addition to meaningful information about existing heterogeneity and possible QTL locations in current cultivars.

The objectives of this study were to evaluate whether advanced common bean lines differ in phenological, morphological, grain yield and cooking quality characters; to study the linear correlations between these characters; and to select superior lines for these characters for use in breeding programs. For this purpose, 14 common bean lines of trial Use and Cultivation South -Brazilian Bean (VCU - SB) were growing in normal rainy 2012/2013 and in dry season 2013 in Santa Maria, Rio Grande do Sul, Brazil. Data were subjected to analysis of individual and joint variance, using the F test at 5 % probability. If the effect of line and control was significant, the stratification of averages was performed by the Scott-Knott test at 5 % probability. Interaction line x growing season significant was observed for the characters: number of days from emergence to flowering, reproductive period, cycle, lodging, stay green, number of lateral branches, number of pods per plant, number of grains per plant, number of grains per pod, weight of 100 grains, grain yield, grain length and width. The line and control evaluated differed significantly among the characters: number of days from emergence to flowering, cycle, number of nodes on main stem, width and thickness of grains, grain brightness and time of cooking, allowing you to select improved lines for these characters. Positive linear correlation of high magnitude was observed between grain yield and number of pods per plant (r = 0.632) and weight of 100 grains (r = 0.942), while the grain yield and the number of days from emergence to flowering (r = -0.857) and the cycle (r = -0.677) had high negative linear correlation. The LP 09-40 line and BRS Valente control have the lower note of lodging in the two growing seasons, allowing the use of these blocks of crosses to obtain lines with erect architecture. The CNFP 10794 and DF 06-17 lines may be used as parents in hybrid combinations for presenting high yield and reduced cooking time and high yield and early cycle, respectively. / Os objetivos deste trabalho foram avaliar se as linhagens avançadas de feijão diferem quanto aos caracteres fenológicos, morfológicos, de produção e de qualidade de cozimento; estudar as correlações lineares entre esses caracteres; e selecionar linhagens superiores para esses caracteres para uso em programas de melhoramento. Para tanto, foram avaliadas 14 linhagens de feijão do Ensaio de Valor Cultivo e Uso Sul-brasileiro de Feijão (VCU-SB) em cultivo de safra 2012/2013 e de safrinha 2013 em Santa Maria, Rio Grande do Sul, Brasil. Os dados obtidos foram submetidos à análise de variância individual e conjunta, usando o teste F a 5% de probabilidade. Sendo o efeito de linhagens significativo, a estratificação das médias obtidas foi realizada pelo teste de Scott-Knott a 5% de probabilidade. Interação linhagem x época de cultivo significativa foi observada para os caracteres: número de dias da emergência a floração, período reprodutivo, ciclo, acamamento, stay green, número de ramos laterais, número de vagens por planta, número de grãos por planta, número de grãos por vagem, massa de 100 grãos, produtividade de grãos, comprimento e largura de grãos. As linhagens e as testemunhas avaliadas diferiram significativamente para os caracteres: número de dias da emergência a floração, ciclo, número de nós no ramo principal, largura e espessura dos grãos, luminosidade dos grãos e tempo de cozimento dos grãos, possibilitando a seleção de linhagens superiores para esses caracteres. Correlação linear positiva de alta magnitude foi observada entre a produtividade de grãos e o número de vagens por planta (r = 0,632) e a massa de 100 grãos (r = 0,942), enquanto que a produtividade de grãos e o número de dias da emergência a floração (r = -0,857) e o ciclo (r = -0,677), apresentaram alta correlação linear negativa. A linhagem LP 09-40 e a testemunha BRS Valente apresentam as menores notas de acamamento nas duas épocas de cultivo, o que possibilita o uso dessas em blocos de cruzamentos para a obtenção de linhagens com porte ereto. As linhagens CNFP 10794 e DF 06-17 poderão ser utilizadas como genitores em combinações híbridas por apresentarem alta produtividade de grãos e reduzido tempo de cozimento e alta produtividade de grãos e ciclo reduzido, respectivamente.

The ability to identify germplasm and select traits accurately is fundamental to successful plant breeding. Pedigrees and molecular markers facilitate these processes; however misleading experimental results can occur when incorrect relationships and/or cultivar names are recorded. Molecular markers can identify these inconsistencies, and with advances in genotyping technology these diagnostics can be done faster and more objectively. This study aimed to develop molecular marker assays and graphical genotyping methodologies for cultivar identification, seed purity assessment and trait selection in oat (Avena sativa L.). KBioscience’s Allele-Specific PCR (KASP™) and genotyping-by-sequencing (GBS) technologies were applied to a set of current Canadian oat cultivars to evaluate their utility for identifying cultivars and detecting intra-cultivar variation. Both KASP™ and GBS detected different extents of heterogeneity among a set of 160 seeds that originated from four seed sources of four cultivars. In both cases, the detected variation did not appear to be limited to a specific cultivar or seed source, reinforcing that all cultivars are heterogeneous. Graphical genotyping localized heterogeneity to specific chromosome regions, thereby distinguishing physical contamination from true genetic heterogeneity and heterozygosity. Pre-existing genotype data for 700 oat cultivars and breeding lines were also used to construct graphical genotypes for pedigree validation and discovery of potential sources for favourable quantitative trait loci (QTL) alleles. This methodology used historical QTLs and anchoring markers to identify 25 putative “high oil” allele carriers. The results from this study will provide diagnostic tools for cultivar identification and pedigree validation, in addition to meaningful information about existing heterogeneity and possible QTL locations in current cultivars.