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1
Siddique, Abu Bakar. "Effects of seed production environment and post harvest management on seed production, viability and vigour of seeds of pea and flax". Thesis, Bangor University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369444.
Testo completo
2
MARIN, MARIA. "Improving seed quality in large-scale production of native seed". Doctoral thesis, Università degli studi di Pavia, 2017. http://hdl.handle.net/11571/1214854.
Testo completoAbstract (sommario):
The use of native species has been increasingly advocated to achieve the sustainable recovery of degraded areas and in Europe considerable effort has also been invested into grassland restoration using such species. However, little attention has been paid to the evaluation and significance of aspects of the seed quality of native species, which may have implications for the success of these projects. The current research examined three aspects of seed quality in the context of commercial seed production and the use of seed in the restoration of vegetation. Firstly, the effect of plant and seed responses to a range of maternal environments during seed production was examined using the perennial herb Primula vulgaris as a model. Different shading conditions, imposed in the field over two seasons during seed maturation, produced a range of red : far-red light ratios (R:FR) received by the parent plants. The competitiveness of P. vulgaris plants grown in the different environments was evaluated though measurements of plant gas exchange, membrane integrity, leaf chlorophyll concentration, photosynthetic efficiency, specific leaf area and above ground plant biomass; the weight and number of seeds produced was also assessed. This revealed the phenotypic plasticity of P. vulgaris and that growth, competitiveness and seed production were favoured in shaded conditions. Subsequent germination of the harvested seeds at five temperatures (5 – 25oC) and high to low R:FR revealed that there was no effect of shading of the maternal plant on seed quality, either the rate of germination or final germination. In addition, the maternal environment did not affect the subsequent light and temperature requirements for germination. An increased germination capacity in response to a higher R:FR for all maternal environments suggested the potential for seedling establishment under vegetative shade only in the presence of canopy gaps. Secondly, the germination potential and dormancy-breaking requirements of 113 commercially available seed lots of eight European native species was examined. This revealed a wide range in the germination of seed lots within a species and surprisingly low levels of dormancy. Alternative and more rapid methods to the routine germination methods were subsequently developed. A tetrazolium testing protocol was developed that predicted germination of each of the eight native species in only two days. In addition, the electrical conductivity (EC) of seed soak water provided a quick and inexpensive measure of final germination in a day and even within a day. However, its application may be limited to large and exalbuminous seeds, such as Cyanus segetum, which are dominated by the embryo and lack an endosperm. The third aspect of seed quality investigated was its impact on establishment and growth of Rhinanthus minor, a hemi-parasite. Ten seed lots from commercial sources were sown in the field and their germination characteristics were investigated in the laboratory. Field emergence was influenced by both the radicle emergence of each lot and the mean germination time, which is indicative of seed vigour. Seeds from four lots with >90% radicle emergence were then germinated to radicle emergence and sown in pots alongside plants of two host species, Lotus corniculatus and Holcus lanatus. Plant establishment, height and flowering density were evaluated for the hemi-parasite, while plant biomass was measured for both R. minor and its host. A longer lag period (lower vigour) was associated with higher levels of seedling mortality and lower plant vigour, in terms of plant height and biomass accumulation, and was also reflected in the parasitic impact of the seed lots, with the least vigorous seed lot having no impact on the biomass of its host, Lotus corniculatus. These observations highlight that the quality of the seed is significant to the potential use of R. minor as a hemi-parasite.
3
Goszka, Abigail R. "Seed Production and Seed Quality in Red Maple (Acer rubrum L.)". Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1564752025178858.
Testo completo
4
Altıok, Evren Ülkü Semra. "Production of proanthocyanidins from grape seed/". [s.l.]: [s.n.], 2003. http://library.iyte.edu.tr/tezler/master/biyoteknoloji/T000247.rar.
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5
Loeppky, Heather Ann. "Flowering and seed production in meadow bromegrass". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ43515.pdf.
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6
Van, Hest Petrus A. A. M. "Production of potatoes through true botanic seed". Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295248.
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7
Zanakis, George N. "Changes in seed quality of soyabean (Glycine max) during seed production and storage". Thesis, University of Reading, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316161.
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8
Ottman, Michael. "Growing Alfalfa Seed in Arizona". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 1999. http://hdl.handle.net/10150/146965.
Testo completoAbstract (sommario):
3 pp.Due to worldwide shortages of non-dormant alfalfa seed, production opportunities and acreage have increased recently in Central Arizona. Seed production for profitability is challenging. Cultural practices differ from those commonly used in forage production. This article outlines management recommendations that may help to accomplish profitable seed alfalfa yields.
9
Lucas, Nicholas. "Factors influencing seed production and seed storage in watercress (Rorippa nasturtium-aquaticum L. Hayek)". Thesis, University of Reading, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292499.
Testo completo
10
Zhou, Dongfang. "Seed Germination Performance and Seed Coat Mucilage Production of Sweet Basil (Ocimum basilicum L.)". Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/49553.
Testo completoAbstract (sommario):
Sweet basil (Ocimum basilicum L.) is a warm season herb usually propagated from seeds. Establishment of basil is difficult as seed germination may be limited, particularly during field seeding at cold soil temperatures. The germination of six cultivars (\'Italian Large Leaf\', \'Italian Large Leaf\' 35X, \'Nufar\', \'Genovese\', \'Genovese Compact Improved\' and \'Aroma 2\') of sweet basil seeds were tested on a one dimensional thermo-gradient table over temperatures ranging from 0 to 50"C. At temperatures below 20"C, germination among cultivars was more variable and the mean time to germination (MTG) increased to greater than 25 days for some cultivars. Germination declined sharply and had a sudden termination at high temperatures above 40"C for all six cultivars. There were statistical differences among the cultivar base temperatures, which ranged between 10.1 and 13.3"C. The optimal and ceiling temperatures for germination were similar and did not differ statistically among the cultivars compared in this study. The average optimal temperature for all cultivars was 35 ± 0"C, while the average ceiling temperature was 43 ± 1.3"C. Stored seeds (> 5 years) had lower seed vigor and lower germination percentage, also lower ceiling temperature compared with the fresh seeds of the same cultivar (\'Italian Large Leaf\'), but the base temperatures were the same for both new and old seeds.
Sweet basil (Ocimum basilicum L.) seeds produce a thick layer of mucilage around the pericarp within minutes after hydration. Mucilage is most prevalent among plant species adapted to surviving in arid sandy soils, though its significance in determining ecological fitness is unclear. The mucilage produced by seeds is reported to be composed of cell-wall polysaccharides that are deposited in testa pericarp cells during development. In this study, sweet basil seeds were examined using light and environmental scanning electron microscopy. The mucilage of basil seeds is held together by columnar structures that unfolded from the pericarp and helped hold and stabilize the mucilage to the outer surface. The mucilage was removed using diluted hydrochloric acid to compare performance of seeds with and without mucilage. Mucilage removal did not inhibit seed germination under ideal laboratory conditions but decreased the water content of seeds significantly. The water content of intact seeds was almost 4 times greater than seeds without mucilage. Mucilage enabled seeds cling to an incline board set to a steeper angle than seeds without mucilage. The fully hydrated seeds approached zero water potential, so the mucilage did not prevent seeds from fully hydrating. Soil (media) germination testing showed the seeds with mucilage had higher germination percentage than the seed without mucilage on several different types of media. Seeds with mucilage also had higher survival percentages after 10 days on different types of media. Basil seeds mucilage acts as a reservoir to hold loosely bound water at high water potential so it is available for seed germination and early seedling development.Master of Science
11
Prescher, Finnvid. "Seed orchards - genetic considerations on function, management and seed procurement /". Umeå : Dept. of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200775.pdf.
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Chorney, Brenda. "Manitoba seed production, an econometric analysis of value added". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62708.pdf.
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Benzel, Katie Rebecca. "Defoliation effects on Spotted Knapweed seed production and viability". Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/benzel/BenzelK0508.pdf.
Testo completoAbstract (sommario):
Spotted knapweed (Centaurea stoebe L.) is a deeply taprooted perennial forb infesting millions of hectares of rangeland in western North America. Spotted knapweed forms large monocultures, which lowers plant diversity, reduces livestock and wildlife forage, and increases surface water runoff and sediment yield. It can produce 5,000-40,000 seeds m-2 year-1, and often produces new flowers after prescribed sheep grazing or mowing defoliates spotted knapweed plants during the bolting or flowering stage. Research has yet to determine if new flowers produced following spring/summer defoliation produce viable seeds by the end of the growing season. The purpose of this 2-year study was to determine the appropriate timing(s) or combination(s) of timings of defoliation on spotted knapweed to reduce viable seed production. Ten spotted knapweed plants, located on spotted knapweed-infested rangeland in west-central Montana, were hand-clipped for each of the following treatments: 1) 35-40% relative utilization of above-ground biomass when plants were in the bolting stage; 2) 100% of buds removed at late-bud/early-flowering stage; 3) 100% of flowers removed at full-flowering stage; 4) Treatment 1+Treatment 2; 5) Treatment 1+Treatment 3; 6) Treatment 2+Treatment 3; 7) Treatment 1+Treatment 2+Treatment 3; and 8) unclipped control. The number of buds/flowerheads per plant, number of seeds per plant, percent viability of seeds, and number of viable seeds per plant were determined when seeds were in the well-developed stage, but seedhead bracts were still tightly closed (mid-August through September). Clipping at any timing or combination of timings reduced the number of buds/flowerheads per plant (P < 0.01), number of seeds per plant (P < 0.01), percent viability of seeds (P < 0.01), and number of viable seeds per plant (P < 0.01) both years compared with the unclipped control. Clipping during the bolting stage reduced the number of viable seeds by nearly 90% compared with no clipping. Clipping during the late-bud/early-flower or full-flower stage reduced the number of viable seeds by nearly 100% compared with no clipping. Defoliation of spotted knapweed via prescribed sheep grazing or mowing in summer should effectively suppress viable seed production of spotted knapweed.
14
Nyarko, George. "Flowering and seed production of cabbage for the tropics". Thesis, Nottingham Trent University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444651.
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Tshisola, Steve Ndondji. "Improved potato (Solanum tuberosum) seed production through aeroponics system". Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86240.
Testo completoAbstract (sommario):
Thesis (MScAgric)--Stellenbosch University, 2014.ENGLISH ABSTRACT: The potato can be considered as one of the most important food crops in many African countries. The potential of this crop is reflected in the large increase in area of production where Africa showed the highest rate of growth within the developing world over the past twenty years. The multiplication rate of potatoes is very low compared to other crops. Therefore it is essential to investigate methods of increasing the number of minitubers produced from disease free in-vitro plantlets. There is a number of potato propagation procedures that are currently being used worldwide to multiply seed potatoes. As aeroponics is still a relatively new technique that has not been researched extensively for the production of minitubers, a study relating to the production practises including the nutritional requirements of potato minitubers produced in a aeroponic system were undertaken. Potato plantlets, cv BP1, were grown aeroponically at two different densities (20 and 30 plants/m2) and four harvest intervals (7, 10, 14 and 18 days). The interaction between harvesting intervals and plant densities did not influence plant growth, minituber quality or yield. Best results were realised when harvesting every 7 days with a higher total tuber number over the growing period. Harvest interval also influenced the phosphorus and copper concentration in minitubers. To study the effect of Calcium (Ca) application rate, potato plantlets of cultivars Up-to-date, Mnandi, Buffelspoort and BP1 were grown at four different Ca levels (8.40, 6.75, 5.10 and 3.45 meq/L). The interaction between Ca application levels and cultivars significantly influenced the percentage stolon branching. BP1 had more stolons at the lowest Ca application level and Buffelspoort had more stolons at the full Ca application levels. However, low Ca treatments produced the highest yield. The minituber number and weight harvested were three times more for Mnandi. An aeroponic study on the irrigation frequency (20, 30, 40 and 50 minutes interval) was conducted on four potato cultivars (Up-to-date, Mnandi, Buffelsoort and BP1). Significant differences were noted in the interaction between irrigation frequencies and cultivars for the percentage tuberised plants and stolon and tuber dry mass. When irrigated every 40 minutes, 48% of the Buffelspoort plants produced tubers. Plant height was also significantly affected by the interaction between irrigation frequencies and potato cultivars, with Mnandi producing taller plants when irrigated every 30 minutes. Total tuber number and tuber fresh and dry weight was higher at the irrigation frequency of 20 minutes. The interaction between irrigation frequencies and cultivars on the response to macro and trace elements was not significant for sodium and iron but was for phosphorus, potassium, calcium, zinc and aluminium. A field study was conducted in a greenhouse where potato seed of BP1 obtained from the first trial were graded into different sizes (Small: >20, medium: 20–40 and large: > 40 mm of diameter) and stored at 3 different temperatures (3, 16 and 25oC) for 2 supplementary months before being planted. Sprouting capacity was mostly influenced by temperature regardless of other factors applied to potato seed minitubers such as harvest intervals and sizes. The higher storage temperature of 25oC resulted in tubers with a higher number of sprouts, longer sprouts and with a higher sprouting capacity.
AFRIKAANSE OPSOMMING: Aartappels is een van die belangrikste voedselgewasse in baie lande in Afrika. Die potensiaal van die gewas word gereflekteer in die groot toename in produksie areas, met Afrika wat die vinnigste van al die ontwikkelende lande gegroei het die laaste 20. In vergelyking met ander gewasse is die tempo van planvermeerdering by aartappels baie stadig. Dit is dus essensieel om metodes te ondersoek wat sal help om die aantal miniknolle wat per in vitro plantjie verkry kan word te verhoog. Daar is heelparty plant vermeerderings prosedures wat tans wêreldwyd gebruik word om saad aartappels te vermeerder. Aangesien aeroponika nog steeds ʼn relatiewe nuwe tegniek is wat nog nie ekstensief ondersoek is vir die verbouing van miniknolle nie, is ‘n studie geloods om te kyk na die produksie praktyke, wat insluit die voedingsbehoeftes van aartappel miniknolle in ʼn aeroponika sisteem. Aartappel plantjies, kultivar, BP1, is aeroponies verbou by twee plant digthede (20 en 30 plante/m2) en vier oesintervalle (7, 10, 14 en 18 dae). Die interaksie tussen oesintervalle en plantdigtheid het geen effek gehad op plant groei, miniknol kwaliteit of opbrengs nie. Die beste resultate is verkry waar die knolle elke 7 dae geoes is met ‘n hoër totale aantal knolle oor die groeiseisoen. Die oesinterval het ook ‘n effek gehad op die fosfaat en koper konsentrasie van die miniknolle. Om die effek van die Kalsium (Ca) toedieningspeil te ondersoek is aartappel plantjies; kultivars Up-to-date, Mnandi, Buffelspoort en BP1 gekweek by vier verskillende Ca peile (8.40, 6.75, 5.10 en 3.45 meq/L). Die interaksie tussen Ca toedienings peile en kultivars het ‘n beduidende effek gehad op die persentasie stolon vertakking. BP1 het meer stolons gehad by die laagste Ca toedieningspeil en Buffelspoort het meer stolons gehad by die volle Ca toedieningspeil. Die hoogste opbrengste is egter waargeneem by die laagste Ca toedieningspeil. Die aantal miniknolle en oes massa was drie keer meer vir Mnandi. ‘n Aeroponiese studie op die besproeiingsfrekwensie (20, 30, 40 en 50 minuut intervalle) is gedoen met vier aartappel kultivars (Up-to-date, Mnandi, Buffelsoort en BP1). Beduidende verskille is opgemerk in die interaksie tussen besproeiings frekwensie en kultivars vir die persentasie plante met knolle en stolon en knol droë massa. Met besproeiings elke 40 minute het 48% van die Buffelspoort plante knolle produseer. Plant hoogte is ook beduidend beïnvloed deur die interaksie tussen besproeiingsfrekwensie en aartappel kultivar met Mnandi plante wat hoër was wanneer dit elke 30 minute besproei is. Die totale aantal knolle en knol vars- en droë massa was hoër wanneer daar elke 20 minute besproei is. Die interaksie tussen besproeiings frekwensie en kultivars op die makro- en mikro element inhoud van die knolle was nie beduidend vir natrium en yster nie, maar wel vir fosfaat, kalium, kalsium, sink en aluminium. ‘n Potproef is gedoen in ‘n kweekhuis waar aartappel saad van BP1 verkry vanaf die eerste proef nadat knolle verdeel is in verskillende grootte klasse (klein: < 20mm, medium: 20-40mm en groot: >40mm) en gestoor is by drie verskillende temperature (3, 16 en 25oC) vir 2 addisionele maande voor plant. Spruit ontwikkelings kapasiteit was meestal beïnvloed deur temperatuur ten spyte van ander behandelings soos oes intervalle en knol grootte. Die hoër bergings temperatuur 25oC het aanleiding gegee tot knolle met ‘n hoër aantal spruite, langer spruite en ‘n hoër spruit ontwikkelings kapasiteit.
16
Landeen, Melissa L. "Mountain Big Sagebrush (Artemisia tridentata ssp vaseyana) Seed Production". BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5740.
Testo completoAbstract (sommario):
Big sagebrush (Artemisia tridentata Nutt.) is the most widespread and common shrub in the sagebrush biome of western North America. Of the three most common subspecies of big sagebrush (Artemisia tridentata), mountain big sagebrush (ssp. vaseyana; MBS) is the most resilient to disturbance, but still requires favorable climactic conditions and a viable post-fire seedbank for successful unassisted recovery. This study was designed to assess MBS seed production throughout post-fire recovery. We performed 2 pilot studies to develop methods for estimating seed production and plant age. The results of the pilot studies and a space-for-time substitution strategy were used to measure seed production on 13 sites ranging from 10-33 years post-fire. We hypothesized that seed rain (mean seeds produced/ m2) would peak before stand density had maximized due to decreasing individual plant fecundity (mean seeds produced/ plant) in high density stands. We measured population density and individual plant fecundity for three size classes of MBS and used forward stepwise regression analysis to identify environmental factors influencing seed production over time. Density for small (basal stem diameter (BSD) <1 cm) and medium-sized (BSD=1-3 cm) plants was consistently low and was not affected by time since fire (TSF), while large-sized (BSD > 3 cm) plant density increased steadily with TSF (p=0.0002). Plant fecundity decreased with TSF for all three size classes (p range = 0.019 – 0.0506), with large plants dominating reproductive output. Small and medium-sized plant fecundity was negatively correlated with winter precipitation (p range = 0.0106-0.0174), while large plant fecundity was positively correlated with winter precipitation (p<0.0001) and negatively correlated with elevation (p=0.0001). Despite losses in plant fecundity over time for all size classes, steady recruitment in population density resulted in increased seed rain (p=0.0039), suggesting that increases in stand density compensated for losses in individual plant fecundity. Results partially support our hypothesis that the time required for MBS seed rain to be maximized was not tightly bound to indicators of stand maturation. Understanding the factors that influence post-fire seed production can help land managers better manage for successful recovery by providing them with tools for evaluating seed production capabilities of MBS communities.
17
Leclerc, Yves. "The production and utilization of potato microtubers". Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41512.
Testo completoAbstract (sommario):
A protocol is presented for the rapid (28 days) induction of microtubers on micropropagated layered potato plantlets of 'Kennebec', 'Russet Burbank' and 'Superior' in medium devoid of growth regulators. With this method the addition of coumarin, 6-(2-chloroethyl)-trimethylammonium chloride and 6-benzylamino-purine to the microtuberization medium either had no effect or significantly reduced microtuber weight per plantlet. Increasing the incubation period from 28 to 56 days significantly increased the weight of microtubers per plantlet and the proportion of microtubers heavier than 1 gram. Increasing the volume of microtuberization medium from 50 to 100 ml significantly increased the number of microtubers per plantlet. Microtuber dormancy periods were cultivar-specific and microtubers $ le$250 mg had longer dormancy periods as compared to microtubers $>$250 mg. A positive correlation was established between endogenous abscisic acid levels and microtuber dormancy periods. Microtubers $ le$250 mg had lower specific gravity, fewer eyes and produce fewer sprouts than microtubers $>$250 mg. Microtuber-derived plants were generally single-stemmed. Severe physiological ageing treatment ($>$2500 degree-days) had no effect on microtuber sprout development, stem number, tuber number and only minimally influenced tuber weight of microtuber-derived plants. Decreasing field in-row planting density from 30 to 10 cm reduced tuber weights and numbers per plant but increased them on a per hectare basis. Economic analysis indicated that optimum planting density varied depending on plantlet cost. The optimum planting density was 10 cm if the cost of the plantlet was $0.10 or less, 20 if plantlet cost were from $0.10 and $0.20 and 30 cm for plantlet cost greater than $0.20. A potato seed tuber certification program adapted to the needs and constraints of Egypt is presented.
18
Baloyi, Rebecca Tshilambilu. "Technical efficiency in maize production by small-scale farmers in Ga-Mothiba, Limpopo Province, South Africa". Thesis, University of Limpopo, 2011. http://hdl.handle.net/10386/1419.
Testo completoAbstract (sommario):
Thesis (M.Agric. (Agricultural Economics)) -- University of LimpopoMaize is the most important cereal crop grown in South Africa. This crop is produced throughout the country under diverse environments. The study only focuses on the technical efficiency because it is an important subject in developing agriculture where resources are limited, but high population growth is very common. Technical efficiency is the ability of a farmer to obtain output from a given set of physical inputs. Farmers have a tendency of under and/or overutilising the factors of production. The main aim of this study was to analyse the technical efficiency of small-scale maize producers in Ga-Mothiba rural community of Limpopo Province. The objective of the study was to determine the level of technical efficiency of smallscale maize producers and to identify the socio-economic characteristics that influence technical efficiency of small-scale maize producers in Ga-Mothiba. Purposive and Snowball sampling techniques were used to collect primary data from 120 small-scale farmers. Cobb-Douglas production function was used to determine the level of technical efficiency and Logistic regression model was used to analyse the variables that have influence the technical efficiency of maize production. Cobb-Douglas results reveal that small-scale farmers in Ga-Mothiba are experiencing technical inefficiency in maize production due to the decreasing return to scale, which means they are over-utilising factors of production. Logistic regression results indicate that out of 13 variables included in the analysis as socio-economic factors, 10 of them (level of education, income of the household on monthly basis, farmer`s farming experience, farm size, cost of tractor hours, fertiliser application, purchased hybrid maize seeds, membership to farmers` organisation, is maize profitable) were found to be significant and 3 (gender, age and hired labour) are non-significant. However, farm size was found to be the most significant variable at 99% level, showing a positive relationship to smallscale maize producer`s technical efficiency. Therefore, it is recommended that government should do the on-farm training since farmers mainly depend on trial and error and farmers` should have access to enough arable land and tractor services. However, farmers need to be trained on matters relating to fertiliser application, on the amount of seeds a farmer should apply per ha, and the importance of using hybrid seed.
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Murphy, Carrie June. "Greenhouse production of microgreens growth media, fertilization and seed treatments /". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 0.32 Mb., 89 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1435839.
Testo completo
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Wiese, Jessica Linsay. "Establishment and seed production of native forbs used in restoration". Thesis, Montana State University, 2009. http://etd.lib.montana.edu/etd/2009/wiese/WieseJ0809.pdf.
Testo completoAbstract (sommario):
The importance of incorporating native wildflowers into seed mixtures for disturbed land revegetation projects is widely known and accepted. However, further assessment of weed management approaches is a necessary step to successfully establish and produce native wildflower seed. We examined the impact of pre and post-emergence herbicides alone and in combination with hand weeding on 5 wildflower species [slender white prairie clover (Dalea candida(Michx). ex Willd), blanketflower (Gaillardia aristata Pursh), fuzzy tongue penstemon (Penstemon eriantherus Pursh var. eriantherus), silverleaf phacelia (Phacelia hastata Douglas ex Lehm.), and prairie coneflower (Ratibida columnifera (Nutt.) Woot. & Standl)] under greenhouse and field conditions. Herbicides evaluated included Treflan (trifluralin) 189 l/ha, Lorox (linuron) 1.121 kg/ha., Permit (halsulfuron) 91 g/ha., Plateau (imazapic) 560 g/ha, and Prowl (pendimethalin) 4.2 l/ha. The objectives of this study were to 1) determine wildflower seedling tolerance to post-emergence herbicides, 2) evaluate the effect of pre-and post-emergence herbicides on native wildflower seedling establishment, weed control, and wildflower seed production. For objective 1 a randomized block design was used and repeated twice. A Monte Carlo resampling assessed herbicide damage and a randomized block design analysis of variance (ANOVA) assessed herbicide impact on fresh and dry biomass. Results indicated that the D. candida and R. columnifera were minimally affected by herbicide treatments, while G. aristata and P. hastata were strongly affected, the first by linuron and halosulfuron and the last by halosulfuron and imazapic. Objective 2 assessed hand weeding and pre and postemergence herbicide effects on native wildflowers. A randomized block design was used to assess wildflower establishment, percentage cover, yield, and seed germination and viability, along with weed community composition and cover as a function of weed management approach. Data were analyzed with a randomized block design analysis of variance (ANOVA) to test for differences in wildflowers seedling emergence, percent cover of wildflowers, and seed yield. Wildflower species responded uniquely to weed management, indicating caution should be used when applying herbicides to the tested species. Specifically, emergence of P. eriantherus, D. candida and P. hastata were negatively affected by trifluralin, indicating this herbicide may not be suited for the tested wildflowers.
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McClain, William Edward. "Phosphorus nutrition in tall fescue from stockpiling to seed production /". Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4870.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 28, 2007) Vita. Includes bibliographical references.
22
Vasquez, Castillo Wilson Arturo. "Seed production, dormancy and commercialisation of Solanum phureja in Ecuador". Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415897.
Testo completo
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Yousuf, Rawa. "Novel polyhydroxybutyrate (PHB) production using a waste date seed feedstock". Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/novel-polyhydroxybutyrate-phb-production-using-a-waste-date-seed-feedstock(70246fcd-0c95-4a31-a0be-0d337c22aefe).html.
Testo completoAbstract (sommario):
Polyhydroxybutyrate (PHB) is a biodegradable, linear polyester that has potential as a promising alternative to petrochemical derived plastics as it possesses the same properties as several current and widely used synthetic, non-biodegradable petrochemical-based plastics. PHB is a natural polyester which is accumulated by many bacteria as an intracellular store of energy and carbon, under stress conditions; limited in one or more essential nutrient, with the carbon source in excess. Currently the PHB production cost is far greater than that of petroleum based plastics. Recent research, therefore, has focused on improving the cost- effective synthesis of PHB from different substrates and microorganisms. The improvement of fermentation processes and strains allowing for PHB to be produced from an inexpensive carbon source is required to compete with synthetic plastics and to mimic their desired properties. The goal of the work reported in this thesis is to assess the suitability of using waste date seed as a feedstock for PHB production under various stress conditions. Date seeds have The novelty of this study The results include fructose hydrolysis from date seeds and the development of a mass transfer model to describe the process, demonstrating that the high nutrient content of date seeds makes them a promising raw material for microbial growth and that a meaningful amount of PHB can be produced. Using fructose rich waste date seed derived medium, with an initial fructose concentration of 10.8 g/l, maximum dry cell weight and PHB concentrations of 6.3 g/l and 4.6 g/l, respectively, were obtained, giving a PHB content of 73%. An investigation into the suitability of using waste date seed oil extract as an alternative carbon source for PHB synthesis was also carried out. This date seed oil was used as the sole carbon source in a series of microbial fermentation experiments, and the results demonstrate that date seed oil is a feasible substrate for PHB production. A maximum dry cell weight (DCW) of 14.35 g/l was obtained, with a PHB content of 82%, using 20 g/l of date seed oil. Subsequently, the effect of using mixed-substrate (date seed hydrolysate media and date seed extracted oil) on PHB synthesis was investigated using various ratios of substrate feeding. A ratio of 1:1 fructose to oil produced the highest biomass and PHB concentrations of 15.22 g/l and 12.36 g/l, with PHB content 84.1%, respectively. Solid state fermentation using polyurethane foam (PUF) as inert solid support also proved to be a successful alternative for traditional SSF method for PHB production with ease. The maximum PHB production was 0.169±0.03 g/g PUF and biomass was 0.4±0.003 g/g PUF. This work results demonstrate that the use of a generic waste date seed medium as a feedstock for PHB synthesis is technically feasible. It is shown that waste date seed provides a novel approach to produce value added products, in this case biopolymer (PHB). The specific studies carried out lead to the wider outlook that a general feedstock derived from date palm by-product, seeds, has potential to be utilised to synthesise a wide range of products based on the microorganism used. More improvement of this process to develop the efficient production of nutrients as well as improve product yields and subsequently, integration of the process into a broader biorefining process would be an essential contribution in the improvement of the sustainable bio-products industries. ï¿1⁄4 a high nutrient content, are available in large quantities and are relatively cheap. lies in the fact that waste date seed can be used as the feedstock for biopolymer production, based on the development of various techniques to make these nutrients bioavailable for the bacterium, Cupriavidus necator for PHB accumulation.
24
Muyekho, Francis Jacob Namasake. "Environmental and agronomic factors affecting seed production in annual medics". Thesis, Adelaide Thesis (Ph.D.)--University of Adelaide, Department of Plant Science, 1993. http://hdl.handle.net/2440/21661.
Testo completo
25
Muyekho, Francis Jacob Namasake. "Environmental and agronomic factors affecting seed production in annual medics". Adelaide Thesis (Ph.D.)--University of Adelaide, Department of Plant Science, 1993. http://hdl.handle.net/2440/21661.
Testo completo
26
Loveday, Rachel Ellen Leonard. "Influence of Seed Treatment on Tobacco Mosaic Virus Incidence in Tobacco Seedlings and Virus Distribution in Greenhouse Transplant Production". Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/31396.
Testo completoAbstract (sommario):
Tobacco mosaic virus (TMV) is an economically important pathogen that has been studied for over one hundred years. Seedlings, seed coats, and nutrient solution were assayed for the presence of the virus and seed treatments were tested on seeds. Double antibody sandwich enzyme-linked immunosorbent assay (DAS ELISA) and biological local lesion assay data were collected. Seed coats from seed collected from TMV infected plants were always positive for TMV regardless of chemical treatment. Seed from infected source plants have lower germination than seed from healthy plants. Trisodium phosphate and hydrochloric acid treatments reduced virus infection of seedlings when grown under controlled conditions. Virus particles were serologically and biologically detected in both the leaves and roots of seedlings mechanically inoculated with TMV. Nutrient solution collected from 28 day old seedlings, 12 days post inoculation, tested positive for biologically active TMV by ELISA and infectivity assay. Infected water in float bed production could facilitate viral movement to all seedlings sharing nutrient solution. Seed transmission of TMV was shown to occur at a rate of 0.2%. This is in contrast to other research attempting to demonstrate seed transmission where visual symptoms on seedlings have been used to assess seed transmission.Master of Science
27
Haring, Steven C. "Harvest Weed Seed Control: An Integrated Weed Management Strategy for Organic and Conventional Production Systems". Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/78827.
Testo completoAbstract (sommario):
Harvest weed seed controls (HWSC) destroy weed seeds that are retained by the plant at crop harvest, which would typically be spread by the harvester along with other field residues. HWSC exploits coincidental maturity between crops and weeds, so an experiment was designed to collect weed seeds as they shatter throughout the growing season and through a simulated harvest delay. This experiment monitored four economically important broadleaf species and two grass species in a soybean (Glycine max (L.) Merr.) field. Results indicated that broadleaf species shattered seed at rates accelerating through the growing season, while grass species shattered more seed early in the growing season. Field experiments in organic and conventional winter wheat (Triticum aestivum L.) fields infested with Italian ryegrass (Lolium perenne L. ssp. multiflorum (Lam.) Husnot) compared two HWSC techniques to grower-standard weed management programs in each system, including both no-till and full-till standard treatments in the conventional system. Italian ryegrass populations were monitored, and wheat yield was measured both before and after HWSC application. In both organic and conventional cropping systems, HWSC treatments did not provide better Italian ryegrass control than the grower-standard treatments. The conventional program including tillage boosted Italian ryegrass populations. These results suggest that HWSC treatments did not enhance Italian ryegrass control compared to grower-standard practices in either the organic or conventional systems. Additionally, broadleaf weeds may retain enough seeds to be viable targets for HWSC. Incorporating best practices, such as a timely crop harvest, is key for understanding and optimizing HWSC.Master of Science
28
Kornacki, Catherine. "MANIPULATING OIL SEED BIOCHEMISTRY TO ENHANCE THE PRODUCTION OF ACETYL-TAGS". Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/35753.
Testo completoAbstract (sommario):
Master of ScienceBiochemistry and Molecular Biophysics Interdepartmental Program
Timothy P. Durrett
Using vegetable oils directly as an alternative biofuel presents several problems as such oils typically possess poor fuel qualities including high viscosity, low volatility, and poor cold temperature properties. The ornamental shrub Euonymus alatus produces unusual acetyl-1,2-diacyl-sn-glycerols (acetyl-TAGs) that have an acetyl group in the sn-3 position instead of a long chain fatty acid. The presence of this sn-3 acetyl-group give acetyl-TAGs properties desirable for biofuels, such as reduced viscosity, comparted to the normal long chain triacyglycerols found in most vegetable oils. Acetyl-TAGs are synthesized by the Euonymus alatus diacylglycerol acetyltransferase (EaDAcT) and Euonymus fortunei diacylglycerol acetyltransferase (EfDAcT) enzymes. Both enzymes catalyze the transfer of an acetyl group from acetyl-CoA to diaclglycerol (DAG) to produce acetyl-TAGs. Previous work demonstrated that expression of EaDAcT combined with the suppression of a diacylglycerol aceyltransferase (DGAT1) in Camelina sativa led to seeds with 85 mol % acetyl-TAGs. Increasing acetyl-TAG levels further was explored using two strategies. Over expression of citrate lyase to increase the pool of acetyl-CoA to be used as a substrate for the acetyltransferase enzymes failed to increased levels of acetyl-TAGs. A second approach involved expressing EfDAcT in Camelina sativa. EfDAcT has demonstrated higher activity in vitro and in vivo and its expression in yeast leads to approximately 50 % higher levels of acetyl-TAGs compared to EaDAcT. The expression of EfDAcT coupled with the suppression of DGAT1 in Camelina sativa resulted in 90 mol % acetyl-TAGs in the transgenic seeds. Levels of EfDAcT protein analyzed in developing transgenic Camelina sativa seeds across a 40 day time period were highest at 15 and 20 days after flowering. Following these time points acetyl-TAG accumulation increased rapidly, coinciding with the higher enzyme expression levels. The optimization of additional promoters to ensure expression of EfDAcT in the last half of seed development could represent another way to further increase acetyl-TAGs in the future.
29
Settipalli, Satyaprakash R. "Synthetic seed production for germplasm storage of Hydrastis canadensis L. (goldenseal)". Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5530.
Testo completoAbstract (sommario):
Thesis (M.S.)--West Virginia University, 2007.Title from document title page. Document formatted into pages; contains vii, 48 p. : col. ill. Includes abstract. Includes bibliographical references (p. 40-42).
30
Settle, Thomas A. "Tall fescue seed production alley cropped in a hardwood tree plantation". Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5088.
Testo completoAbstract (sommario):
Thesis (M.S.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 3, 2008) Includes bibliographical references.
31
Rojas, Jose Santos. "Production and post-harvest technology for hybrid true potato seed (TPS)". Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363810.
Testo completo
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Tacarindua, Custodio Ramos Paulo. "Effects of Increased Temperature on Growth and Seed Production of Soybean". Kyoto University, 2013. http://hdl.handle.net/2433/180632.
Testo completoAbstract (sommario):
Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第17964号
農博第2032号
新制||農||1019(附属図書館)
学位論文||H25||N4808(農学部図書室)
30794
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 奥本 裕, 教授 稲村 達也
学位規則第4条第1項該当
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Mukassabi, Tarek A. "Scots pine (Pinus sylvestris L.) seed production at Wybunbury Moss, Cheshire and factors affecting seed germination and early establishment". Thesis, Keele University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.572460.
Testo completoAbstract (sommario):
Scots pine (Pin us sylvestris) growing at Wybunbury Moss, Cheshire on a small floating bog (Schwingmoor) some 400 km south of its current native limit was studied. Seed production of trees that have been growing on the site for several centuries, and the . susceptibility of seed and seedlings to waterlogging were investigated. Cones matured between September and March and seed shedding began in early April. A strong relationship was found between tree size and seed production which allowed the prediction ,,"A "'~'J' .A- of annual seed production. One hectare of woodland surrounding the central bog produced approximately 1 350 000 seeds annually with a germination percentage of 64%. The estimated number of seeds reaching the central bog every year was c. 16 000 seeds. Vegetation type, topography and water table depth were the most important factors dictating germination and seedling success. Three weeks of dry conditions was likely sufficient for Scots pine seedlings to establish whatever the water table level afterwards. Scots pine seeds from Wybunbury had the capability to germinate and survive a water table of up to 4 cm below the surface and often less. Six hummocky microhabitats of Sphagnum, Sphagnum-Ericaceae, Sphagnum-Cyperaceae, Ericaceae, Cyperaceae and Pure peat formed 8, 15, 33, 17, 26 and 1 %, respectively, of the central bog area. Seedling survival in each microhabitat was 2.1, 1.5, 1.6, 1.8, 1.9 and 0.5%, respectively. Adding all these factors together led to the prediction that on the central bog at Wybunbury there should be 200 new juveniles every year. Since a management aim is for this to be <100, suggestions on specific woodland thinning/clearance are made to achieve this target. iii
34
Nelson, Ryan Lee. "Small Burnet (Sanguisorba minor Scop.) Response to Herbicides Applied Postemergence". DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/1479.
Testo completoAbstract (sommario):
Small burnet (Sanguisorba minor scop.) Is a hardy, relatively long lived evergreen forb native to Eurasia that has potential to improve grazinglands and extend grazing into late fall and winter. Trials evaluating small burnet tolerance to spring and fall postemergence herbicide applications were conducted at the Utah State University Evans farm in Millville, UT. Two small burnet genotypes were grown in a randomized complete block design with a split-plot arrangement. Twelve treatments, clethodim, clopyralid, imazamox, 2,4DB, metribuzin, aminopyralid, pendimethalin, dimethenamid-P, bromoxynil, dicamba, quinclorac, and an untreated were applied at moderate field use rates either spring or fall of the establishment year. Plots were rated for visual injury on a 0 to 100 scale where 0 = no injury and 100 = complete mortality. Ratings were done 7, 14, 60 days after treatment (DAT) and the spring following treatment. Seed yield, seed viability, and dry matter yield (DMY) were determined. Fall treatments of aminopyralid reduced seed yield 65%, seed germination 43%, and DMY 67%. Fall applied imazamox treatments reduced DMY by 36%, and seed yield by 33%, but did not impact germination. Visual injury was greatest from spring and fall applied aminopyralid treatments with ratings of 24% and 79%. Spring applied treatments did not impact seed yield or seed germination. Results suggest that clethodim, metribuzin, quinclorac, clopyralid, dimethenamid-P, bromoxynil, and pendimethalin cause little or no injury to small burnet.
35
Shakya, J. D. "The production of potatoes from true potato seed by transplanting or field sowing". Thesis, University of Reading, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354099.
Testo completo
36
Kawasaki, Yukie. "Scalable Bio-Production of High Value Products in Bacteria". DigitalCommons@USU, 2015. https://digitalcommons.usu.edu/etd/4609.
Testo completoAbstract (sommario):
Biliverdin IXα is a green bile pigment produced by enzymatic cleavage of a tetrapyrrole ring of heme by heme oxygenase. While biliverdin IXα is emerging as an effective cytoprotectant, the conventional method for producing biliverdin IXα by chemical conversion of animal bile is not suitable for large scale production. A novel scalable production method was pursued via bacterial fermentation. Recombinant Escherichia coli strains were obtained by sequence optimization and plasmid transformation of a cyanobacterial heme oxygenase gene. Further strain development was done by plasmid overexpression of a native E. coli flavodoxin gene as a possible electron donor for heterogeneous heme oxygenase. The resulting strains were grown in a fed-batch culture system optimized for biliverdin IXα production.
Syringomycin E is a lipodepsinonapeptide produced by certain strains of Pseudomonas syringae pv. syringae by nonribosomal peptide synthesis. Though syringomycin E had been considered a phytotoxin in the past, recent research results indicate that syringomycin E is a natural fungicide that is not toxic to animals and plants. Syringomycin E is a potential fungicide especially for use in the organic agriculture sector. New strains of P. syringae pv. syringae were isolated through ultraviolet mutagenesis and screenings for enhanced capability to produce syringomycin E especially under agitated conditions. Fermentative production was conducted in a newly formulated medium and the product was purified through a large scale chromatography system using organic-compatible solvents. Purified syringomycin E was tested on cucumber seeds to examine its antifungal activity against a soil-borne pathogen Pythium ultimum. Syringomycin E was able to inhibit Pythium infection and protected seeds and seedlings without developing disease symptoms.
This dissertation research showed scalable production of two natural products, biliverdin IXα and syringomycin E in bacterial platforms. Strain development by gene recombination and mutation was done to obtain bacterial strains capable of overproducing desired metabolites. The resulting strains were grown in fermenters to maximize the yields under agitated conditions. Monitoring growth parameters and medium modifications were critical to achieve large scale production.
37
Du, Randt Marius Louis. "The influence of nutrient solutions on growth, seed production and seed quality of broccoli (Brassica oleracea L. var. italica Plenck)". Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6642.
Testo completoAbstract (sommario):
Thesis (MScAgric (Agronomy))--University of Stellenbosch, 2011.Includes bibliography.
ENGLISH ABSTRACT: Little is known about the nutrient requirements of broccoli grown for seed production. During 2006 and 2007 broccoli were grown for seed production in sand bags in a net structure, using a drain to waste hydroponic system. The experimental design was a randomized complete block with seven treatments replicated in four blocks. In 2006 seven nutrient solution treatments were tested. The Standard solution based on Steiner’s universal solution was compared with different levels of N, S, K and Ca with regard to the effect on total biomass, nutrient concentration, nutrient assimilation, seed yield and quality. No significant differences in total biomass produced were found. Total dry mass increased by 225% from the mature head stage until harvest of seed. Nutrient concentration in plant samples were not influenced by treatments except where low levels of K and S in nutrient solutions led to significantly lower levels of K and S concentrations. The total assimilation of elements were calculated to determine the effect of the much longer growth period needed for seed production in comparison to normal head production on nutrient requirements. Major elements assimilated ha-1 was: N 173.0 kg, P 35.5 kg, K 348.4 kg, Ca 114.7 kg, Mg 30.5 kg, S 42.2 kg. The seven treatments used during 2007 included three of the treatments which were used in 2006 as well as treatments with foliar sprays containing Ammonium Nitrate and Calcium Metalosate. The standard solution treatment was also used in 2007 to compare results with 2006. Plant analysis done on plants from the standard solution (2006 & 2007) showed similar trends. As the plants developed towards maturity there was a relative increase in concentration in the top plant parts (pods, flowers and stems) for Ca, Mg and S. Contrary, N and P concentration declined. The minor elements, Fe, Mn and B also increased in concentration in the top plant parts at harvest indicating a strong relative flow of these elements to the top plant parts towards maturation. Concentration values of major elements in plant samples were generally different when the two years were compared. Element concentrations in the seed pods were in general higher than in the rest of the plant indicating the pods as a strong sink on the plants. During both years the two best nutrient solutions for yield were the same, namely the Standard solution and Standard - K which contain low levels of K. During 2006 no significant differences in seed quality were found. During 2007 no significant differences were found for seed quality measurements, except for size (of the cotyledons). The results indicate that no special adjustments need to be made to the Standard solution in order to produce good broccoli seed yield of good quality. As substantial differences in nutrient solution composition did not significantly affect the quality of broccoli seed produced. Seed yield was however significantly affected by nutrient solution composition. Key words: Brassica seed, broccoli seed, seed production, broccoli nutrition, hydroponic production, broccoli production, nutrient assimilation.
AFRIKAANSE OPSOMMING: Min inligting is bekend rakende die voedingsbehoeftes van brokkoli wat gekweek word vir saadproduksie. Gedurende 2006 en 2007 is brokkoli gekweek vir saadproduksie in sakke sand in ‘n net struktuur met ‘n oop hidroponiese besproeiingstelsel. Die proefontwerp was ‘n ewekanisige geheel blok met sewe behandelings wat ewekansig binne bloke toegeken is en herhaal is in vier blokke. Sewe voedingsmengsel behandelings is gedurende 2006 toegepas. Die Standaard mengsel is geskoei op Steiner se universele mengsel en dit is vergelyk met verskillende vlakke van N, S, K en Ca t.o.v. die invloed daarvan op biomassa produksie, voedingselement konsentrasie, voedingselement assimilasie, saad opbrengs en saad kwaliteit. Biomassa geproduseer het nie wesenlik verskil nie. Totale droë massa het met 225% toegeneem vanaf die volwasse kop tot die oes stadium. Die konsentrasie van voedings elemente in plant monsters is nie beïnvloed deur behandelings nie behalwe in gevalle waar lae konsentrasies van K en S in die voedingsmengsels gelei het tot lae konsentrasies van K en S in plantontledings. Die totale opname van voedingselemente is bereken om die effek van die veel langer groeiperiode wat benodig word vir saadproduksie in vergelyking met normale kop produksie te bepaal t.o.v. voedingselement behoefte. Makro element opname per hektaar was as volg: N 173.0 kg, P 35.5 kg, K 348.4 kg, Ca 114.7 kg, Mg 30.5 kg, S 42.2 kg. Die sewe behandelings van 2007 het drie behandelings van 2006 ingesluit asook behandelings van blaarbespuitings met Ammonium Nitraat en Kalsium Metalosaat. Die Standaard voedingsmengsel is weer gebruik ten einde die resultate van 2006 en 2007 te vergelyk. Voedingselement ontledings op plante van die Standaard mengsel (2006 & 2007) is vergelyk en het soortgelyke tendense aangedui. Soos wat plante ontwikkel het na volwassenheid was daar ‘n relatiewe toename in konsentrasie in die boonste plant dele (peule, blomme en stele) van Ca, Mg en S. In teenstelling hiermee het die konsentrasies van N en P afgeneem. Die mikro elemente Fe, Mn en B het ook in konsentrasie toegeneem in die boonste plant dele teen oes wat daarop dui dat daar ‘n sterk relatiewe vloei van hiedie elemente na die boonste plant dele plaasvind met volwasse wording. Die konsentrasie vlakke van makro elemente in plantontledings het in die algemeen wesenlik verskil tussen die twee jare. Die voedingselement konsentrasies was in die algemeen hoër in die saad peule as in die res van die plant wat daarop dui dat die peule as ‘n sterk sink op die plant funksioneer. In beide jare was die hoogste opbrengs afkomstig van die Standaard voedingsmengsel en die Standaard – K mengsel wat lae vlakke van K bevat het. Gedurende 2006 is geen wesenlike verskille in saadkwaliteitsnorme gevind nie. Soortgelyke resultate is gevind in 2007 behalwe vir grootte van die kiemblare. Die resultate dui daarop dat dit nie nodig is om die Standaard voedingsmengsel samestelling te verander ten einde goeie opbrengs saad van goeie gehalte te produseer nie. Wesenlike verskille in voedingsmengsels het geen invloed op die kwaliteit van brokkoli saad gehad nie. Saad opbrengs is egter wesenlik beïnvloed deur die samestelling van die voedingsmengsels. Sleutel woorde: brassica saad, brokkoli saad, saad produksie, brokkoli voeding, hidroponiese produksie, brokkoli produksie, voedingstof assimilasie.
38
Beam, Shawn Christopher. "Evaluation of integrated weed management techniques and their nuances in Virginia crop production". Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/95248.
Testo completoAbstract (sommario):
Herbicide resistant weeds are driving implementation of integrated weed management (IWM). A new tactic to manage weeds is harvest weed seed control (HWSC), which targets weed seeds retained on the plant at crop harvest and either destroys, removes, or concentrates them. Research is limited on the effectiveness of HWSC in US cropping systems. For HWSC to be effective it is important to know when and how many seed are shed from a weed species in relation to crop harvest. Research was conducted to quantify when weed seed are shattered from 6 economically important weed species, four broadleaf (redroot pigweed, common ragweed, common lambsquarters, and common cocklebur) and two grass species (large crabgrass and giant foxtail). Results indicate that among summer annuals, broadleaf species retain larger proportions of their seed compared to grass species at the first opportunity for soybean harvest. As harvest was delayed, more seeds shattered from all species evaluated, indicating timely harvest is critical to maximizing HWSC effectiveness. Studies were conducted on grower fields in Virginia to evaluate the effectiveness of HWSC (field residue and weed seed removal). Results indicate that HWSC can significantly reduce populations of Italian ryegrass in wheat and common ragweed in soybean in the next growing season, but reductions were not observed for Palmer amaranth in soybean. Investigating IWM system for common ragweed control in soybean, HWSC was found to be less effective than soybean planting date (i.e. double cropping after wheat) at reducing common ragweed populations. However, the effectiveness of HWSC varied by location. If HWSC adoption were to become widespread, weeds could adapt by shedding seed earlier in the season. Research was conducted by growing Palmer amaranth populations from across the eastern US in a common garden. Currently there are differences in flowering time and seed shatter among Palmer amaranth populations based on the location of the maternal population, indicating potential for adaptation. This research demonstrates that HWSC is a viable option for weed management in US cropping systems but needs to be stewarded like any other weed management tool.Doctor of Philosophy
Herbicide resistance in weeds is a growing problem in the US and around the world. Alternative methods of weed control must be adopted to maintain crop yields in the presence of herbicide-resistant weeds. Researchers and extension specialists strongly advise growers to adopt an integrated weed management (IWM) approach. Integrated weed management involves implementing multiple weed control tactics during a growing season. By using multiple methods of weed control within a given season the chances of weeds becoming resistant or adapting to any single tactic is reduced. Harvest weed seed control (HWSC) is a new tactic developed in Australia in response to herbicide resistance. HWSC targets weed seeds retained on the plant at crop harvest. In a normal crop harvest, the combine removes the grain and spreads crop residues (leaves, stalks, and other plant parts), including weed seeds, back across the field. When HWSC is implemented, weed seeds are destroyed (narrow windrow burning, cage mills) or concentrated and potentially removed from the field (chaff carts, direct bale, chaff lining). Thus, HWSC limits the number of weed seeds returned to the soil seed bank. There is limited research on HWSC and its integration with other tactics, in US cropping systems. For HWSC to be effective it is necessary for weed seeds to be retained on the mother plant in sufficient quantities at crop harvest. Research was conducted in Virginia to determine when weed seeds are shattered during the soybean growing season for 6 economically important weed species, four broadleaf (redroot pigweed, common ragweed, common lambsquarters, and common cocklebur) and two grass species (large crabgrass and giant foxtail). The broadleaf species retained >85% of their seed until the first opportunity for soybean harvest (mid-October). In the grass species, more seed shattered prior to soybean harvest with 50% of large crabgrass and 74% of giant foxtail seed being retained at the first opportunity for soybean harvest. When harvest was delayed seed continued to shatter and less was captured using HWSC. This research indicates broadleaf species are more suitable candidates for HWSC than grass species, among summer annuals. Further research on the ability of seed to germinate in relation to when seeds were shed was conducted on redroot pigweed, common ragweed and common lambsquarters. Results indicate that there are variable effects on germination of these species depending on when they were shed. HWSC was implemented on grower fields to assess the impact on weed populations of 3 weed species (Italian ryegrass, common ragweed, and Palmer amaranth). These experiments compared conventional harvest and HWSC (field residue and weed seed removal) when all other management strategies were the same within that field. Italian ryegrass tiller density in wheat varied by location but was reduced up to 69% in the spring following implementation of HWSC. By wheat harvest, HWSC reduced Italian ryegrass seed head density 67% at one location compared to conventional harvest. In soybean, common ragweed densities were reduced by 22 and 26% prior to field preparation and postemergence herbicide applications, respectively, in the HWSC plots compared to the conventional harvest plots. No differences were observed in common ragweed density by soybean harvest. No differences were observed with Palmer amaranth densities at any point during the soybean growing season. This research show that HWSC can reduce weed populations but is variable and additional research is still needed. IWM experiments were established across Virginia to compare soybean planting date (full season or double cropped), + cover crop (cereal rye/wheat or no cover), and + HWSC (field residue removal) to evaluate the best management strategy for common ragweed in soybean. Across all locations, double cropping soybean behind wheat had the greatest impact on common ragweed densities at the end of the first season. The impact of double cropping soybeans on common ragweed population is due to the emergence pattern of common ragweed; majority of common ragweed emerges prior to planting double cropped soybean (mid-June to early-July). HWSC was variable and only reduced common ragweed density at one of three locations. Widespread adoption of HWSC could place a selection pressure on weeds to shatter seed earlier in the season. A common garden experiment was conducted in Blacksburg, VA to assess Palmer amaranth populations collected from central Florida to southern Pennsylvania for differences in flowering time, time to seed shatter, and other phenotypic traits. Results indicate that latitude of the maternal population influences time to first flower with a 0.53 d reduction in flowering time for every degree north in latitude the maternal population was collected from. The strongest predictor of Palmer amaranth flowering time was emergence date/daylength. For every day emergence was delayed the time to first flower was reduced by 0.31 and 0.24 d for female and male plants, respectively. Time from emergence or first flower to first seed shatter was reduced by 0.48 or 0.17 d, respectively, for each day emergence was delayed. These results indicate that differences exist currently among Palmer amaranth populations and the selection pressure of HWSC could push these populations to flower and shatter seed early.
39
Gray, David. "Studies on seed quality and plant establishment in relation to crop production". Thesis, University of Edinburgh, 1986. http://hdl.handle.net/1842/28147.
Testo completo
40
Madafiglio, Gregory Peter, University of Western Sydney, of Science Technology and Environment College e School of Environment and Agriculture. "Population management of Raphanus raphanistrum L. (wild radish) by regulating seed production". THESIS_CSTE_CIT_Madafiglio_G.xml, 2002. http://handle.uws.edu.au:8081/1959.7/339.
Testo completoAbstract (sommario):
Raphanus raphanistrum L. (wild radish) is a widespread and economically problematic weed of winter crops including wheat (Triticum aestivum L.) in southern Australia. Management of the weed is achieved by a range of non-chemical and chemical techniques. Current management is failing to contain the weed, which is increasing in abundance and distribution. The characteristics of staggered recruitment, dormancy, rapid growth, competitive ability and high levels of seed production contribute to its persistence. The literature review concludes that weeds formed the basis for perpetuation of R. raphanistrum, a claim further investigated by simulation modeling. The effective management of R. raphanistrum should aim to achieve declining populations and this requires the integration of all factors that regulate seed production. Reducing seed production of R. raphanistrum in wheat can be achieved by applying herbicides at reproductive stages of development. This technique has been demonstrated to be an effective, safe and practical method of reducing seed production of R. raphanistrum in wheat. Reducing seed production of R. raphanistrum by herbicides applied at reproductive stages of development is a technique that can be incorporated into an integrated weed management program to improve controlDoctor of Philosophy (PhD)
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Seyed, Mahmoud Soheil. "Production of recombinant carp growth hormone in the seed of Brassica napus". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0004/NQ38503.pdf.
Testo completo
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Ruark, Sarah Johnson. "Evaluation of Biological and Other Novel Seed Treatments for Organic Peanut Production". NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-10312008-133746/.
Testo completoAbstract (sommario):
Poor stands are a constraint on organic peanut production because stand losses of 50% or more are possible with untreated seed. Biological, other novel seed treatments, and soil amendments were tested for efficacy against pre- and post-emergence damping-off in greenhouse, microplot, and field plot trials. Seed of the lines Perry, GP-NC 343, and N03081T were utilized in all trials. Nine treatments were tested in natural soil in the greenhouse. Treatments included Bacillus subtilis (Kodiak), B. pumilus (Yield Shield), Trichoderma harzianum (T-22 PB and Plantshield HC), Muscodor albus, Coniothyrium minitans (Contans), activated charcoal, two separate soil amendments of dried herbage of Monarda didyma cultivars, a commercial fungicide check (Vitavax PC), and an untreated control. Vitavax PC and Kodiak were the only seed treatments with higher percentage emergence and survival than untreated seed. A separate greenhouse experiment was conducted for seed treatments using natural soil or soil infested with field isolates of Aspergillus niger. Seed were treated with Kodiak, copper hydroxide (Champion), Plantshield HC, Kodiak and Plantshield HC combined, Streptomyces griseoviridis (Mycostop), hot water, Vitavax PC, or were left untreated. Seedling emergence and survival was much lower in inoculated versus uninoculated plots. In all plots, treatment with Kodiak increased percentage emergence and survival compared to untreated seed, but was not as effective as Vitavax PC. In uninfested plots, treatment with Champion also increased emergence and survival compared to the untreated check. Field microplot studies in Clayton, NC evaluated seed treated with Kodiak, T. harzianum, activated charcoal, Vitavax PC, or untreated seed on the three peanut lines following wheat, oat, or triticale cover crops, soil amendment with M. albus, or no cover as a control. In both years, the percentage emergence and survival was highest for Perry seeds treated with Vitavax PC. Cover crops did not affect emergence, but M. albus treatment suppressed emergence. In field studies at Lewiston, NC, the three peanut lines were treated with M. albus, Kodiak, T. harzianum, or were untreated. In the 2007 trial, none of the treatments improved stands compared to the untreated check. In 2008, the highest stand counts were produced by seed treated with Kodiak. In both years, the largest stands were N03081T. The most commonly observed pathogen was A. niger. Confounding effects of seed line and seed source prevent assessment of performance from individual cultivars. However, regardless of seed line, in most trials Kodiak seed treatment consistently increased emergence and survival over untreated seed.
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Kaeb, Benjamin Carl. "Management of grape colaspis, Colaspis brunnea (Coleoptera: Chrysomelidae), in seed corn production". [Ames, Iowa : Iowa State University], 2006.
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44
Stepanonytė, Dovilė. "Investigation of rape seed oil methyl ester production and by-product utilization". Master's thesis, Lithuanian Academic Libraries Network (LABT), 2007. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2007~D_20070629.150117-86007.
Testo completoAbstract (sommario):
The problems of rape seed methyl ester (RME) production process by-products utilization were analyzed, statistical data for the capacities of biodiesel production and by-products generation were presented, the prospects of biodiesel production expansion, properties and environmental impact, main production technologies, Lithuanian and foreign countries experience were described, the main aims and tasks of work were defined. The investigation of glycerol – major by-product of RME production process – utilization was accomplished. One of the new possible utilization methods was researched, when combusting glycerol with highly sulphurous (~ 2.0 %) heavy fuel oil to reduce SO2 emissions, which limit value in the flue gas can not exceed 1700 mg/Nm3 (according to EU Directive 1999/32EC and LAND 43-2001 „Norms for the exhaust of pollutants from large fuel burning equipment“).
The heavy fuel oil – glycerol emulsion was prepared in the pilot plant operating in the laboratory conditions, the most optimal ratio (1:1) for heavy fuel oil emulsification was estimated, the dispersivity investigation of heavy fuel oil - glycerol emulsion samples was performed.
The experimental heavy fuel oil and obtained emulsion combustion investigations were carried out in VGTU Institute of Thermal Insulation pilot plant and in the thermal oxidation boiler „UMISA-CR/11,9 (13)“ at JCS „Rietavo veterinarinė sanitarija“. The CO, NOx, SO2 and particulate matter concentration values for heavy fuel oil and... [to full text]Baigiamajame darbe išnagrinėtos rapso aliejaus metilo esterio (RME) gamybos proceso šalutinių produktų utilizacijos problemos, pateikti statistiniai duomenys apie biodyzelino gamybos bei susidarančių šalutinių produktų apimtis, aprašytos biodyzelino gamybos plėtros perspektyvos, savybės bei poveikis aplinkai, pagrindinės gamybos technologijos, Lietuvos bei užsienio šalių patirtis šioje srityje, apibrėžti pagrindiniai darbo tikslai ir uždaviniai. Atliktas RME gamybos proceso pagrindinio šalutinio produkto – glicerolio – utilizacijos tyrimas. Išanalizuotas vienas iš naujų galimų utilizavimo būdų - deginti glicerolį kartu su sieringu (~ 2,0 %) mazutu, siekiant sumažinti SO2 emisijas, kurių nustatyta ribinė vertė dūmuose negali būti didesnė kaip 1700 mg/Nm3 (pagal ES Direktyvą 1999/32EC ir LAND 43-2001 „Išmetamų teršalų ir didelių kurą deginančių įrenginių normos“). Laboratorinėmis sąlygomis stendiniame įrenginyje paruošta mazuto-glicerolio emulsija, nustatytas optimaliausias mazuto emulgavimo gliceroliu santykis (1:1), atlikti mazuto emulsijos bandinių homogeniškumo tyrimai. Eksperimentiniai mazuto bei gautų emulsijų deginimo bandymai buvo atlikti VGTU Termoizoliacijos instituto eksperimentiniame stende bei UAB „Rietavo veterinarinė sanitarija“ termooksidaciniame katile „UMISA-CR/11,9 (13)“. Išmatuotos mazuto ir mazuto-glicerolio emulsijos CO, NOx, SO2 ir kietųjų dalelių emisijos bei palygintos su jų didžiausiomis leistinoms vertėmis. Remiantis gautais rezultatais pateiktos... [toliau žr. visą tekstą]
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Najamussahar. "Seed production and storage of pea (Pisum sativum L.) for improved quality". Thesis, Bangor University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298635.
Testo completo
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Al-Soqeer, Abdulrahman A. "The potential of seed soaking in sorghum (Sorghum bicolor L. Moench) production". Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408443.
Testo completo
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Osenga, Joseph John. "Use of seed treatments and inoculants in no-tillage soybean production practices". [Ames, Iowa : Iowa State University], 2009.
Cerca il testo completo
48
Madafiglio, Gregory Peter. "Population management of Raphanus raphanistrum L. (wild radish) by regulating seed production". Thesis, View thesis View thesis, 2002. http://handle.uws.edu.au:8081/1959.7/339.
Testo completoAbstract (sommario):
Raphanus raphanistrum L. (wild radish) is a widespread and economically problematic weed of winter crops including wheat (Triticum aestivum L.) in southern Australia. Management of the weed is achieved by a range of non-chemical and chemical techniques. Current management is failing to contain the weed, which is increasing in abundance and distribution. The characteristics of staggered recruitment, dormancy, rapid growth, competitive ability and high levels of seed production contribute to its persistence. The literature review concludes that weeds formed the basis for perpetuation of R. raphanistrum, a claim further investigated by simulation modeling. The effective management of R. raphanistrum should aim to achieve declining populations and this requires the integration of all factors that regulate seed production. Reducing seed production of R. raphanistrum in wheat can be achieved by applying herbicides at reproductive stages of development. This technique has been demonstrated to be an effective, safe and practical method of reducing seed production of R. raphanistrum in wheat. Reducing seed production of R. raphanistrum by herbicides applied at reproductive stages of development is a technique that can be incorporated into an integrated weed management program to improve control
49
Madafiglio, Gregory Peter. "Population management of Raphanus raphanistrum L. (wild radish) by regulating seed production /". View thesis View thesis, 2002. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030403.112142/index.html.
Testo completoAbstract (sommario):
Thesis (Ph.D.) -- University of Western Sydney, 2002."A thesis submitted for the degree of Doctor of Philosophy (Ph.D.) in the Centre for Landscape and Ecosystems Management, University of Western Sydney ... May 2002" Includes bibliography (leaves 159-177) and other bibliographical references.
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Rethwisch, Michael D., Mark Reay, Jessica Grudovich, D. Michael Ramos e Jessica Wellman. "Evaluation of AuxiGro® WP and Foliar Fertilizers on Bermudagrass Seed Production". College of Agriculture, University of Arizona (Tucson, AZ), 2005. http://hdl.handle.net/10150/203817.
Testo completoAbstract (sommario):
AuxiGro® WP was evaluated for effects on bermudagrass seed production in the Palo Verde Valley of far eastern California. Four rates of this product, in addition to a 4 oz./acre rate with two fertilizers were tested, as were the fertilizers only to separate treatment effects. Highest yields from subplot harvests were noted from the 2 and 4 oz./acre rates of AuxiGro® WP, and germination percentages from these treatments and resultant pure live seed were also numerically higher (81-99 lbs./acre) than that noted from untreated bermudagrass, although most plant parameters did not result in statistical difference.