Dissertations / Theses on the topic 'Crop and Pasture Production'
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Mills, Annamaria. "Understanding constraints to cocksfoot (Dactylis glomerata L.) based pasture production." Phd thesis, Lincoln University. Agriculture and Life Sciences Division, 2007. http://theses.lincoln.ac.nz/public/adt-NZLIU20070717.161658/.
Full textVarella, Alexandre Costa. "Modelling lucerne (Medicago sativa L.) crop response to light regimes in an agroforestry system." Lincoln University, 2002. http://hdl.handle.net/10182/1477.
Full textTonmukayakul, Nop. "Water use efficiency of six dryland pastures in Canterbury." Lincoln University, 2009. http://hdl.handle.net/10182/1498.
Full textLeeks, C. R. F. "Determining seed vigour in selected Brassica species." Lincoln University, 2006. http://hdl.handle.net/10182/1274.
Full textSchaffer, M. J. "Spatial aspects of bumble bee (Bombus spp. Apidae) foraging in farm landscapes." Lincoln University, 1997. http://hdl.handle.net/10182/2243.
Full textMoot, Derrick J. "Harvest index variability within and between field pea (Pisum sativum L.) crops." Lincoln University, 1993. http://hdl.handle.net/10182/1285.
Full textBithell, S. L. "An evaluation of Solanum nigrum and S. physalifolium biology and management strategies to reduce nightshade fruit contamination of process pea crops." Lincoln University, 2004. http://hdl.handle.net/10182/1160.
Full textMonks, D. P. "The vegetative and reproductive development of balansa clover." Lincoln University, 2009. http://hdl.handle.net/10182/1337.
Full textFu, J. "Effects of different harvest start times on leafy vegetables (Lettuce, Pak Choi and Rocket) in a reaping and regrowth system." Lincoln University, 2008. http://hdl.handle.net/10182/670.
Full textBeyers, Hendrik Philippus. "The effect of haloxyfop-R-methyl ester and imazamox herbicides, tine or no tillage and nine different medic cultivars on the seed and dry matter production as well as the quality of medic pastures." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52517.
Full textENGLISH ABSTRACT: The aim of this study was to determine the effect of a grass herbicide, a broadleaf herbicide with some grass control capabilities, method of tillage (tine and no-tillage) at planting of wheat as well as different medic cultivars on the regeneration, dry matter (OM) production and quality of a medic pasture. The trial was conducted at Langgewens experimental farm in the Swartland wheat producing area. Nine medic cultivars of three different species were evaluated after being sprayed with either haloxyfop-R-methyl (HAL) ester or imazamox (IMI) and subjected to either a tine tillage or a no tillage treatment at planting of wheat. Soil samples were taken during January 2000 to determine the size of the medic and weed seedbank as well as the degree of dormancy in the medic seeds, while OM samples were taken throughout the growing season to determine the OM production of the different medic cultivars and weed species. OM samples taken during October 1998 on the same pasture, were used to determine the crude protein (CP) and neutral detergent fibre (NOF) content of the pasture. The samples were subjected to in vitro digestion and the digestibility of pasture CP (OCP), NOF(ONOF) and DM (DOM)were determined. Results showed that seedling establishment differed between cultivars used, herbicide treatments applied as well as the crop stage in the rotation. The cultivars produced more seedlings where IMI was applied compared to HAL as well as where the area consisted of two year pasture compared to one year pasture (1998) and one year wheat (1999). After a year of pasture and a year of wheat, cultivars Sephi and Paraggio produced the most seedlings, while Caliph and Orion produced the least. Caliph however, showed a very high degree of seed dormancy while Orion's low seedling establishment was due to its sensitivity to the IMI herbicide used. Little difference was found between the nine cultivars early in the season (July - August) with regard to cumulative OM production, except for Orion, whose growth was severely damaged by the IMI treatment. At the end of the growing season (October), the cultivar Caliph's cumulative OM production (2010.1 kg/ha) was significantly higher than all the other cultivars, except for Parabinga (1053. 4 kg/ha). Oifferent pasture samples, of which the botanical composition was known, was analysed for CP, NOF, OOM, OCP and ONOF. There was no significant difference in pasture composition during 1998 but variation in the pasture composition did however cause the IMI treatment, compared to the HAL treatment, to have a lower ONOFand OOMcontent. A modelling procedure was used to predict the pasture quality parameters (CP, NOF, OOM,OCP and ONOF) from the pasture composition (medic hay, medic pods, grassy and broadleaf weeds). This prediction of CP, NOF, OOM, ONOF and OCP from the pasture components had a relative low accuracy (49 -74.1 %) and a further refinement of this model for possible use on farms in order to improve grazing management and animal production is advised. In conclusion it could be said that broadleaf weed control caused a definite increase in medic seed and OMproduction, but Orion should not be used with an IMI herbicide. All the cultivars, except for Orion, produced enough seedlings up to the second year to ensure sustainability of the medic pasture. All the cultivars, except for Orion, produced a sufficient amount of OM early in the growing season. Caliph however, produced by far the most OM later in the growing season. A reduction of broadleaf weeds and medic pods will increase the digestibility of NOFand OMand therefore increase the quality of the pasture. Pods however are an important part of summer forage and the aim should therefore rather be to reduce the number of broadleaf weeds in the pasture.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die effek van 'n gras en breëblaar onkruiddoder (wat sekere grasse beheer), metode van bewerking tydens die saai van koring asook nege verskillende medic kultivars op die regenerasie, droë materiaal produksie en kwaliteit van medic weidings te bepaal. Die proef is gedoen op Langgewens proefplaas wat geleë is in die Swartland koring produserende gebied. Nege medic kultivars is geëvalueer nadat die weiding met of haloxyfop-R-metiel ester (HAL) of imazamox (IMI) onkruiddoders gespuit is en onderwerp is aan of 'n vlak tand of geen bewerking tydens die saai van koring. Grondmonsters is geneem in Januarie 2000 om die grootte van die medic en onkruid saadbank asook om die graad van dormansie in die verskillende medic kultivars se sade te bepaal. Droë materiaal monsters is gedurende die 2000 groeiseisoen geneem om die droë materiaal produksie van die verskillende medic kultivars asook onkruid spesies te bepaal. Droë materiaal monsters is gedurende Oktober 1998 geneem en gebruik om die ruproteïn (CP) en neutraaloplosbare vesel (NDF) inhoud van die weiding te bepaal. Die monsters is in vitro verteer en die verteerbaarheid van CP (OCP), NDF (ONOF) en droë materiaal (DOM) is bepaal. Resultate wys dat saailing vestiging verskil tussen die verskillende kultivars wat gebruik is, verskillende onkruiddoder behandelings asook die stadium van die weidings/koring. Die kultivars het meer geproduseer waar die weiding met IMI behandel is in vergelyking met waar HAL toegedien is, asook waar koring nog nie gesaai is nie. Na 'n jaar van weiding en 'n jaar van koring, het die kultivars Sephi en Paraggio die meeste saailinge, en Caliph en Orion die minste saailinge gehad. Caliph het egter 'n hoë graad van dormansie in sy saad getoon, terwyl die swak vestiging van Orion die gevolg is van die kultivar se hoë sensitiwiteit teenoor IMI. Min verskil is gevind tussen die nege kultivars, vroeg in die groei seisoen (Julie - Augustus), wat kumulatiewe droë materiaal produksie betref, behalwe vir Orion wat erg beskadig is deur die IMI behandeling. Aan die einde van die groeiseisoen (Oktober 2000) was die kumulatiewe droë materiaal produksie van die kultivar Caliph (2010.1 kg/ha) betekenisvol hoër as al die ander kultivars behalwe vir Parabinga (1053.4 kg/ha). Weidingsmonsters, waarvan die botaniese samestelling bekend was, is ontleed vir CP, NDF, DDM, DCP en DNDF. Daar is geen betekenisvolle verskille gevind in die botaniese samestelling van die weidingmonsters geneem in 1998 nie,maar die variasie in botaniese samestelling het veroorsaak dat IMI in vergelyking met HAL 'n laer DNDF and DDM inhoud het. 'n Model is opgestel wat die weidingskomponente (medic hooi, medic peule, gras en breëblaar onkruide) gebruik om die kwaliteits parameters (CP, NDF, DDM, DCP en DNDF) van die weiding te skat. Hierdie skatting van CP, NDF, DDM, DCP en DNDF deur van die weidingskomponente gebruik te maak het 'n relatiewe lae akuraatheid gehad (49 -74.1 %) en verdere verfyning van hierdie model vir moontlike gebruik op plase, ten einde weidings bestuur en diere produksie te verbeter, word voorgestel. Die gevolgtrekking kan gemaak word dat breëblaar onkruidbeheer 'n definitiewe verbetering in die medic saailing en droë materiaal produksie van die medies te weeg gebring het, maar die kultivar Orion behoort nie saam met 'n IMI gebruik te word nie. AI die getoetste kultivars, behalwe Orion, het voldoende saad oorlewing vertoon tot en met die tweede jaar van die rotasie om lewensvatbaarheid van die sisteem te verseker en alle kultivars, behalwe Orion, het voldoende droë materiaal produseer vroeg in die groeiseisoen. Caliph het egter laat in die groeiseisoen by verre die meeste droë materiaal geproduseer. 'n Vermindering in die hoeveelheid breëblaar onkruide en peule in die weiding sal tot 'n verhoging in die verteerbaarheid van NDF en DM lei en dus 'n verhoging in die kwaliteit van die weiding tot gevolg hê. Peule is egter 'n belangrike bron van voedsel aan weidende diere gedurende droë somermaande en die verbetering van weidings moet eerder gedoen word deur te poog om breëblaar onkruide te beheer.
Medeiros, Henrique Rocha de. "Avaliação de modelos matemáticos desenvolvidos para auxiliar a tomada de decisão em sistemas de produção de ruminantes em pastagens." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/11/11139/tde-27112003-100019/.
Full textIn agricultural systems, environment, soil, animals and plants are indissociable components of the production process. Furthermore, the production time-frame is relatively long. These characteristics enhance risk and uncertainty associated with decision alternatives made during the process. One tool which can aid in decision-making in these processes is the use of mathematical modeling. Models are simplified representations of reality and allow for the estimation of responses of the system (e.g., production) as the process is altered or for the description and understanding of processes within the system. The objectives of the present study were to (i) test the Stockpol ® model under the conditions and as a predicting tool for ruminant production systems in Brazil, (ii) validate a herbage accumulation model based on climatic variables, and (iii) evaluate models that estimate forage intake on pasture-based animal production systems. For these purposes, the available literature was surveyed in order to identify the datasets that would fulfill the necessary requirements in terms of amount of information needed for the validation and evaluation exercises. The information were then catalogued in three separate datasets: pasture, animal, and economic indicators. This work allowed for the identification of research areas where information is short (such as the seasonal distribution of annual forage production as well as forage intake by grazing animals), besides the need for standardization of research methods and procedures so that research data generated in different environments and by different research groups in Brazil can be compared on the same basis. Despite the many limitations, if the existing parameters are reviewed or adjusted and/or new input variables are incorporated, the Stockpol ® model may become both a research and a decision-making tool for pasture-based animal production systems in Brazil. The Photothermal Units (PU) model proved suitable as it gave adequate predictions of forage yield of Cynodon spp. grasses considering only daylength and temperature as input variables. In this model, predictions seem to be most accurate when the base-temperature is between 13 and 15 ºC. In the future, more input variables, such as the hidric balance (to fine-tune the water budget) may be incorporated into the model to enhance its prediction ability. The model evaluated to predict forage intake by grazing ruminants will likely need reparametrization and/or use green leaf allowance (green leaf dry mass divided by total liveweight at any one point in time) to be useful in predicting intake on tropical pastures. The model used to predict performance gave poor estimates of weight gain, probably due to the overestimation of the energy cost of grazing and/or the underestimation of the nutritive value of the diet selected. It is expected that, once these issues have been resolved, the performance model can operate in conjunction with both the PU and the intake models so that the major components of the system can be simulated under Brazilian conditions
Childerhouse, Emma. "The effect of a natural plant extract and synthetic plant growth regulators on growth, quality and endogenous hormones of Actinidia chinensis and Actinidia deliciosa fruit : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Horticultural Science at Massey University, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1052.
Full textBates, Andrew John. "Effects of grazing management and pasture composition on the nitrogen dynamics of a dairy farm : a simulation analysis : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Lincoln University /." Diss., Lincoln University, 2009. http://hdl.handle.net/10182/1360.
Full textDickson, Ross L. "The effect of water stress, nitrogen and gibberellic acid on the phytotoxicity of post-emergent herbicides to Avena spp." Lincoln University, 1990. http://hdl.handle.net/10182/1283.
Full textMuraki, Tomohiro. "Effects of alternative grass species on grazing preference of sheep for white clover." Diss., Lincoln University, 2008. http://hdl.handle.net/10182/1095.
Full textKellman, Anthony W. "Rhizobium inoculation, cultivar and management effects on the growth, development and yield of common bean (Phaseolus vulgaris L.)." Diss., Lincoln University, 2008. http://hdl.handle.net/10182/378.
Full textPatterson, R. G. "A study of the soils and agronomy of a high country catchment." Lincoln University, 1993. http://hdl.handle.net/10182/1315.
Full textMcLaughlin, Michael John. "Phosphorus cycling in soil under wheat-pasture rotations /." Title page, contents and summary only, 1986. http://web4.library.adelaide.edu.au/theses/09PH/09phm1615.pdf.
Full textSvinurai, Walter. "Manure production and nutrient management in pasture-based dairy production systems." Thesis, University of Fort Hare, 2010. http://hdl.handle.net/10353/475.
Full textSéguin, Philippe 1974. "Pasture renovation : introduction of legumes in a grass dominated pasture with physical suppression of the resident vegetation." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27907.
Full textChiy, Paul Chu. "Sodium supply for pasture and dairy cow production." Thesis, Bangor University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.331954.
Full textLatta, Roy A. "Improving medic pastures in pasture-wheat rotations in the Mallee district of North-Western Victoria /." Title page, contents and abstract only, 1994. http://web4.library.adelaide.edu.au/theses/09A/09al364.pdf.
Full textO'Connell, Kathleen Ann. "Environmentally sustainable fertiliser nitrogen management practices for pasture production." Thesis, Queen's University Belfast, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426720.
Full textTAKABE, Tetsuko. "Biotechnology of Crop Production and International Consortium." 名古屋大学農学国際教育協力研究センター, 2004. http://hdl.handle.net/2237/8933.
Full textSedibe, Moosa Mahmood. "Optimising water use efficiency for crop production." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53541.
Full textENGLISH ABSTRACT: Poor water management and poor water use efficiency (WUE) have been identified as one of the major problems experienced by vegetable growers in most of the developing countries, including South Africa. This poor management and poor utilization of water have led to a drastic decline in the quality and quantity of available water. In South Africa agriculture uses about 50% of available water. Increasing water demand for domestic, industrial and mining uses, may decrease agriculture's share to less than the current 50%, henceforth, better utilization of this resource is imperative. Selection of a good irrigation system can limit water loss considerably. Some irrigation systems have a potential to save more water than others do. Since irrigation systems affect the WUE of crops, care should be taken when selecting an irrigation system under conditions of limited water quantity. Ebb-and- Flood watering systems have been introduced for effective sub-irrigation and nutrient delivery within closed systems. Such a system was adapted in South Africa, to develop a vegetable production unit for use by families in rural communities, while saving substantial amounts of water. A need to further improve the WUE of this system was subsequently identified. Two studies were conducted at the experimental farm of the University of Stellenbosch (Department of Agronomy). The first trial was conducted under controlled conditions in a glasshouse, and the second under open field conditions. In the first trial, Beta vulgaris (Swiss chard) and Amaranthus spp. ('Imbuya') were grown in two root media; gravel and pumice. In addition, an 'Ebb-and-Flood' and a 'Constant level' system were used with nutrient solutions at two electrical (EC) conductivity levels 1.80 and 3.60 mS cm-I. The results of this (2x2x2x2) factorial experiment indicated that a combination of the 'Ebb-and-Flood' system with gravel as a root medium produced the best results at a low EC, when 'imbuya' was used. A high total WUE was found with 'imbuya', (7.35 g L-I) at EC 1.80 mS cmicompared to a relatively low WUE of 5. 90 g L-I when the 3.60 mS cm-I nutrient solution was used. In the second trial, 'Imbuya's' foliage dry mass, leaf area and WUE was evaluated under field conditions at the Stellenbosch University experimental farm, during the summer of2002. The experimental farm (33°55'S, 18°52'E) is situated in the cooler coastal wine grape-producing region of South Africa with a relatively high annual winter rainfall. This trial was conducted on an alluvial soil, with clay content of 25% and a pH of 5.9 (KC!). A closed 'Ebb-and-Flood' system was compared with two open field irrigation systems ('Drip' and 'Flood') using nutrient solutions at two electrical conductivity levels (1.80 and 3.60 mS cm-i) in all three cases. Foliage dry mass, leaf area as well as WUE was best with 'Drip' irrigation, when a nutrient solution with an electrical conductivity of 3.60 mS cm-i was used. In spite of the fact that additional ground water was available for the soil grown 'Drip' and 'Flood' treatments, the 'Ebb-and-Flood' system outperformed the 'Flood' treatment, especially when the nutrient solution with an EC of 3.6 mS cm-i was used. Insufficient root aeration in the flooded soil could have been a contributing factor. The fact that the 'Ebb-and-Flood' and 'Drip' systems gave the best results when the high EC solution was used to fertigate the plants, may indicate that the plants could have hardened due to the mild EC stress, better preparing them to adapt to the extreme heat that was experienced in the field.
AFRIKAANSE OPSOMMING: Swak: bestuur van water en 'n swak: water-gebruik-doeltreffendheid (WOD) is as een van die belangrikste probleme geïdentifiseer wat deur groente produsente in die meeste ontwikkelende lande, insluitend Suid-Afrika, ervaar word. Hierdie swak bestuur en benutting van water het daartoe bygedra dat 'n drastiese afname in die kwaliteit asook in die kwantiteit van beskikbare water ervaar word. In Suid-Afrika gebruik die landbou-sektor ongeveer 50% van die beskikbare water. Toenemende water behoeftes vir huisgebruik, industrieë en die mynbou mag hierdie 50% aandeel van die landbou sektor laat krimp. Beter benutting van hierdie skaars hulpbron is dus noodsaaklik. Die keuse van goeie besproeiingsisteme mag waterverliese merkbaar beperk aangesien sekere sisteme se water-besparingspotensiaal beter as ander is. Aangesien besproeiingstelsels die WOD van gewasse beïnvloed, is spesiale sorg nodig waar 'n besproeiingstelsel onder hierdie toestande van beperkte waterbronne gekies moet word. 'Ebb-en-Vloed' sisteme kan aangewend word om water en voedingselemente van onder in 'n wortelmedium te laat opstoot en in 'n geslote sisteem te laat terugdreineer. So 'n sisteem is in Suid-Afrika ontwikkel waarmee groente vir families in landelike gebiede geproduseer kan word terwyl water bespaar word. 'n Behoefte om die WOD van hierdie produksiesisteem verder te verbeter is egter geïdentifiseer. Twee ondersoeke is by die Universiteit van Stellenbosch se proefplaas (Departement Agronomie) gedoen. Die eerste proef is onder beheerde omgewingstoestande in 'n glashuis uitgevoer en die tweede onder veld toestande. In die eerste proef is Beta vulgaris (Snybeet) en Amaranthus spp. ('Imbuya') in twee tipes wortelmedia; gruis en puimsteen verbou. 'n 'Ebb-en-Vloed' asoook 'n 'Konstante vlak' besproeiingsisteem is gebruik terwyl voedingsoplossings ook by twee peile van elektriese geleiding (EC) teen 1.80 en 3.60 mS cm-I toegedien is. Die resultate van hierdie (2x2x2x2) fakroriaal eksperiment het aangetoon dat 'n kombinasie van die 'Ebb-en-Vloed' sisteem met gruis as 'n wortelmedium die beste resultate teen 'n lae EC lewer waar 'imbuya' gebruik is. Die WOD met 'imbuya' was hoog (7.35 g L-1) by 'n EC van 1.80 mS cm-I, vergeleke met 'n relatief lae WOD van 5. 90 g L-1 waar die 3.60 mS cm-I voedingsoplossing gebruik is. In die tweede proef is 'Imbuya' se droë blaarmassa, blaar oppervlakte en WOD onder veldtoestande op die Universiteit van Stellenbsoch se proefplaas in die somer van 2002 ge-evalueer. Die proefplaas (33°55'S, 18°52'E) is in die koeler kusstreke van die wyndruif produksiegebied in die winterreëngebied van Suid-Afrika geleë. Hierdie proef is op alluviale grond met 25% klei en 'n pH van 5.9 (KCi) uitgevoer. 'n Geslote 'Ebb-en-Vloed' sisteem is met twee veld-besproeiingsisteme vergelyk ('Drup' en 'Vloed') terwyl voedingsoplossings teen twee peile van elektriese geleiding (1.80 en 3.60 mS cm-I) in al drie gevalle gebruik is. Blaar droëmassa, blaaroppervlakte asook die WGD was die beste met 'Drup' besproeiing waar die EC van die voedingsoplossing 3.60 mS cm-I was. Ten spyte van die feit dat ekstra grondwater vir die 'Drup' and 'Vloed' behandelings beskikbaar was, het die 'Ebben- Vloed' stelsel beter as die 'Vloed' behandeling gedoen veral waar die voedingsoplossing se EC 3.6 mS cm-I was. Swak wortelbelugting was waarskynlik die rede waarom vloedbesproeiing swak produksie gelewer het. Die feit dat die 'Drup' en die 'Ebb-en-Vloed' behandelings in die veldproef die beste gedoen het waar die EC hoog was, mag moontlik met die gehardheid van die plante verband hou wat aan ekstreem warm en dor toestande blootgestel was.
Butler, Holly. "Optimising nutrient use efficiency in crop production." Thesis, Lancaster University, 2016. http://eprints.lancs.ac.uk/83220/.
Full textEllis, Ciaran R. "Valuing wild pollinators for sustainable crop production." Thesis, University of Stirling, 2014. http://hdl.handle.net/1893/22327.
Full textMallory, Ellen B. "Crop/Livestock Integration Effects on Soil Quality, Crop Production, and Soil Nitrogen Dynamics." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/MalloryEB2007.pdf.
Full textBenedict, Katherine A. "Modelling applications to pasture-based beef production in Atlantic Canada." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ49312.pdf.
Full textStewart, Alan V. "Plant breeding aspects of ryegrasses (Lolium sp.) infected with endophytic fungi." Phd thesis, University of Canterbury. Lincoln College, 1987. http://theses.lincoln.ac.nz/public/adt-NZLIU20071005.172250/.
Full textMerfield, C. N. "Predator interactions within a trophic level : Phalangium opilio L. (Arachnida: Opiliones) and mites (Arachnida: Acari)." Diss., Lincoln University, 2000. http://hdl.handle.net/10182/21.
Full textKang, Sideth. "Effect of irrigation on growth and nitrogen accumulation of Kabuli chickpea (Cicer arietinum L.) and narrow-leafed lupin (Lupinus angustifolius L.)." Diss., Lincoln University, 2009. http://hdl.handle.net/10182/1126.
Full textKean, J. M. "Metapopulation theory in practice." Lincoln University, 1999. http://hdl.handle.net/10182/1372.
Full textAtes, Serkan. "Grazing management of subterranean clover (Trifolium subterraneum L.) in South Island (New Zealand)." Diss., Lincoln University, 2009. http://hdl.handle.net/10182/1338.
Full textPayne, Kathryn Marie. "ENHANCED EFFICIENCY NITROGEN FORMULATION EFFECT ON GRASS-LEGUME PASTURE PRODUCTIVITY." UKnowledge, 2019. https://uknowledge.uky.edu/pss_etds/113.
Full textFenby, Nicholas Simon. "Rhizomania - approaches to diagnosis and production of resistant cultivars." Thesis, De Montfort University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391078.
Full textShi, Xiaoqing. "Biotechnological production of antifungal proteins for crop protection." Doctoral thesis, Universitat Autònoma de Barcelona, 2021. http://hdl.handle.net/10803/671681.
Full textLos hongos patógenos de plantas causan importantes pérdidas en las cosechas, poniendo en peligro la seguridad y calidad alimentaria. Los péptidos antimicrobianos (AMPs) muestran una actividad lítica potente y duradera específicamente frente a microorganismos, por lo que tienen un gran potencial como nuevos fungicidas naturales para el control de los hongos patógenos. Su explotación requiere de sistemas de producción rápidos, eficaces, económicos y seguros. El principal objetivo de este trabajo era desarrollar sistemas de producción sostenibles de AMPs, y su caracterización en el control de infecciones fúngicas para avanzar en su aplicación en la agricultura. Las proteínas antifúngicas (AFPs) secretadas por hongos filamentosos son un grupo de AMPs ricos en cisteínas, muy estables, activos específicamente frente a hongos. En este estudio demostramos que las plantas de Nicotiana bentamiana son una excelente biofactoría de AFPs mediante expresión transitoria usando un nuevo vector derivado del virus de mosaico del tabaco. Utilizando este sistema de producción en plantas, hemos producido eficientemente dos AFPs muy activas frente a hongos fitopatógenos, la AfpA de Penicillium expansum y la AfpB de Penicillium digitatum. Hemos descubierto que el compartimento subcelular donde se acumulan las AFPs tiene un impacto importante en la producción obtenida, probablemente porque su compartimentalización evita la toxicidad hacia las células vegetales. Los valores más altos se obtuvieron cuando las proteínas se acumularon en las vacuolas, alcanzando hasta 0,170 mg/g de hoja en el caso de la proteína más activa AfpA y hasta ocho veces más para la AfpB (1,2 mg/g de hoja). También demostramos que los extractos crudos de plantas que contienen AFP son activos frente a hongos, sin necesidad de purificar las proteínas reduciendo considerablemente el procesamiento del material vegetal y los costes de producción. Por lo tanto, el sistema desarrollado es eficiente para la producción de AFPs, y también es económico y seguro ya que se basa en plantas. Además, hemos desarrollado un sistema alternativo para la producción del péptido antifúngico PAF102 que previament no había podido producirse biotecnológicamente. Este sistema se basa en acumular el péptido en las gotas lipídicas (LDs) mediante la fusión a una proteína oleosina de plantas. Mediante esta estrategia, hemos producido PAF102 en semillas de arroz en cantidades de 20 mg por gramo de semilla. Sin embargo, la producción en semillas es lenta y para acelerar el proceso hemos transferido la tecnología de la fusión a oleosinas de plantas al sistema de Pichia pastoris. Usando este nuevo sistema hemos obtenido rendimientos comercialmente relevantes con producciones de 180 mg/l de cultivo en sólo 4 días. La acumulación de PAF102 en las LDs de las semillas de arroz y de la levadura facilita enormemente su extracción por simple flotación en soluciones densas, permitiendo la recuperación de péptido activo frente a hongos patógenos. Finalmente, hemos demostrado que tanto AfpA y AfpB producidas en plantas, como los extractos de plantas enriquecidos estas proteinas, son eficaces en la prevención de infecciones fúngicas en cultivos económicamente relevantes, tales como la podredumbre gris causada por Botrytis cinerea en hojas y frutos de tomate, el quemado del arroz causado por Magnaporthe oryzae, o las infecciones de las semillas de arroz por Fusarium proliferatum. Nuestros resultados proporcionan un sistema de producción sostenible de AFPs y demuestran su eficacia en la protección de las plantas contra las infecciones fúngicas, apoyando firmemente su uso como "fungicidas verdes" eficaces y respetuosos con el medio ambiente en la protección de cultivos y postcosecha.
Plant diseases caused by pathogenic fungi are responsible of important crop losses endangering food security and safety. Antimicrobial peptides (AMPs), exhibiting potent and durable lytic activity specifically against microorganisms, have a great potential as novel natural fungicides for the control of pathogenic fungi. However, viable exploitation of AMPs requires fast, cost-efficient, and safe production systems. The main goal of this work was to develop a sustainable platform for the production of bioactive AMPs, and to characterize them in the control of fungal infections in plants to advance in their application in agriculture. Antifungal proteins (AFPs) secreted by filamentous fungi are a group of highly stable cysteine-rich AMPs that specifically target fungal cells. In this study, we demonstrate that Nicotiana benthamiana plants are an excellent biofactory for producing AFPs through transient expression using a new vector derived from the tobacco mosaic virus. Using this plant-based production system we efficiently produced two different bioactive AFPs, the Penicillium expansum AfpA and Penicillium digitatum AfpB. We found that the subcellular compartment where AFPs are accumulated has an important impact on protein yield, probably avoiding toxicity towards plant cells. The highest yields were achieved when targeting AFPs to vacuoles, reaching up to 0.170 mg/g of fresh leaves of the highly active AfpA and eight times more of AfpB (1.2 mg/g of leaf). We also show that plant crude extracts containing AFPs are fully active against plant pathogens without requiring further protein purification, thus reducing significantly downstream processing. Therefore, the developed system is efficient for the production of AFPs, and also it is economic and safe since it is based on plants. We also developed an alternative system for the production of the linear PAF102 antifungal peptide that was recalcitrant to be produced in biological systems. This system is based on targeting the peptide to lipid droplets (LDs) through the fusion to a plant oleosin protein. Using this oleosin fusion technology, we produced PAF102 in rice seed LDs, reaching moderate yields of about 20 mg of peptide per gram of grain. Production on rice seeds is long process in order to speed the process, we successfully transferred the plant oleosin fusion technology to the Pichia pastoris system. We produced commercially relevant yields of PAF102 in these yeast LDs, reaching values of 180 mg/l of culture in only 4 days. The accumulation of PAF102 in the LDs of rice seeds and yeast facilitated its downstream extraction and recovery by simple flotation on dense solutions, with the recovered PAF102 being biologically active against pathogenic fungi. Finally, we demonstrate that in planta produced AfpA and AfpB, either purified protein or protein extracts enriched with these two proteins, are efficient in controlling important fungal diseases on economically relevant crops, including Botrytis gray mold disease in tomato leaves and fruits, blast disease in rice plants and Fusarium proliferatum infection in rice seeds. Our results provide a sustainable production system of AFPs, and evidence their efficacy on protecting plants from fungal infection, strongly supporting the use of AFPs as environmental friendly and effective “green fungicides” in crop and postharvest protection.
Universitat Autònoma de Barcelona. Programa de Doctorat en Biologia i Biotecnologia Vegetal
(217363), Mei Li. "Genetic diversity, physiology and production of Chinese water chestnut (Eleocharis dulcis (Burm. f.) Trin. ex Henschel)." Thesis, 1998. https://figshare.com/articles/thesis/Genetic_diversity_physiology_and_production_of_Chinese_water_chestnut_Eleocharis_dulcis_Burm_f_Trin_ex_Henschel_/20010443.
Full textChinese water chestnut (Eleocharis dulcis (Burm. f.) Trin. ex Henschel) is a new aquatic vegetable to Australia. Lack of research on this crop greatly limits the understanding of its production performance. Therefore, studies on several aspects of this crop were undertaken to provide a scientific basis for improvement in yield and quality.
Firstly, the genetic relationship of Chinese water chestnuts growing in Australia was assessed by using random amplified polymorphic DNAs (RAPDs). For the genetic
analysis of wild putative E. dulcis, three primers separated the samples from 9 out of 10 sites into two distinct groups: E. dulcis and E. sphacelata. In the genetic analysis of samples from cultivated E. dulcis plants, 96 RAPD markers generated by 14 primers separated the samples from Taiwan (var. Shu-Lin), Hangzhou, China (cv. Da Hong Bao), New South Wales, Australia (unknown variety) and the USA (unknown variety) from the rest of the samples from Australia. The remaining samples were too closely related (0.74-4.4% dissimilarity) to be differentiated.
Secondly, the possibility to extend availability of fresh Chinese water chestnut corms by physiological manipulation (photoperiod control) was evaluated in four
photoperiod experiments. When measured, above -ground growth and dry matter production of the whole plants were not significantly affected by photoperiods (8-24 h). However, corm formation was strongly retarded by long days and promoted by the photoperiod which was shorter than a critical value. Under shorter days, significantly more dry matter was shifted towards corms as well as rhizomes, an
effect that became more pronounced as the period of treatment was lengthened.
Thirdly, Chinese water chestnut production in relation to harvest date and cold storage of 'seed' corms was investigated in two experiments. In the first experiment,
March -planted plants were harvested from July to September. Mature corms from each harvest were subsequently stored at 4°C. In terms of corm formation and
maturation as well as soluble sugar concentration in mature corms, the harvests in August were more favorable. After storage at 4°C for 86 d (harvest on 24 September)
to 159 d (harvest on 15 July), no sign of rot nor flesh deterioration was observed. Loss of fresh weight ranged from 0.46% to 6% with the lower value associated with
the shorter storage duration. Corm germination was also favored by shorter storage period. The highest values for the number of sprouts and stems per viable corm and
the length of the longest stem per viable corm were obtained from the harvests on 29 July (139 d storage), 13 August (130 d storage) and 27 August (116 d storage)
respectively. In the second experiment, corms harvested on different dates over the period July to November were stored at 4°C for four different periods prior to planting. Both harvest date and cold -storage duration exhibited significant influence on soluble solid content (°Brix) with the highest values for the first harvest and no cold storage, although the average °Brix value was low for all treatments. Harvest
date and cold -storage duration also showed significant effects on corm sprouting performance evaluated as the number of sprouts and stems, and the length of the
longest stem per viable corm. Average yield per plant showed little difference across `seed' corm harvest dates with the exception of the last. The fresh weight of individual corms was significantly affected by 'seed' corm harvest date but not by storage duration.
Fourthly, the possibility of Chinese water chestnut in vitro culture was investigated with several different explants and culture media. Among all the explants examined, only young rhizome nodes and tips, dormant buds and corm skin with bud scars (buds removed) responded to in vitro culture by the production of shoots or shoot clusters. Root initiation was readily stimulated in the derived microshoots. The test
tube plantlets were successfully transferred to the screenhouse, and their subsequent performance compared favorably with that of corm -derived plants.
Lastly, a putative Chinese water chestnut disease, tip yellowing and brown stem lesions, which was observed in the greenhouse and in the field, was studied. As no
corresponding symptoms showed up when healthy plants were inoculated with spores derived from the isolates obtained from affected tissue, a nutritional disorder,
perhaps potassium deficiency, was therefore suggested to have been responsible for the symptoms.
(12246268), Alan Andrew Duff. "Growth and development of onions in a subtropical environment." Thesis, 2004. https://figshare.com/articles/thesis/Growth_and_development_of_onions_in_a_subtropical_environment/19365128.
Full text(9800051), Colin Greensill. "Non-invasive assessment of fruit quality by near-infrared spectroscopy for fruit grading in an in-line setting." Thesis, 2000. https://figshare.com/articles/thesis/Non-invasive_assessment_of_fruit_quality_by_near-infrared_spectroscopy_for_fruit_grading_in_an_in-line_setting/13426595.
Full text(9822500), Tika Neupane. "Improving predictability of time to harvest and yield of field grown tomato crops." Thesis, 2016. https://figshare.com/articles/thesis/Improving_predictability_of_time_to_harvest_and_yield_of_field_grown_tomato_crops/13387178.
Full text(9237167), A. Garrett. "The pollination biology of Papaw (Carica papaya L.) in Central Queensland." Thesis, 1995. https://figshare.com/articles/thesis/The_pollination_biology_of_Papaw_Carica_papaya_L_in_Central_Queensland/13416722.
Full text(9798107), Geeta Gautam Kafle. "Some studies on the physiology of Stevia rebaundiana (Bertoni)." Thesis, 2011. https://figshare.com/articles/thesis/Some_studies_on_the_physiology_of_Stevia_rebaundiana_Bertoni_/13457141.
Full text(12804776), Stephen Barry Johnson. "Nitrogen fixation by potential ley pasture legumes for Central Queensland." Thesis, 1997. https://figshare.com/articles/thesis/Nitrogen_fixation_by_potential_ley_pasture_legumes_for_Central_Queensland/20010641.
Full textYield decline following continuous cropping cycles in Central Queensland has been attributed to the declining soil nitrogen status. In this study an assessment of the level of nitrogen fixation was made to assist in the selection of potential ley pasture legumes for use in rotational systems to achieve sustainable cropping yields.
Twenty one winter and summer growing legumes were evaluated for nitrogen fixation in glasshouse trials in two seasons. Nitrogen fixation was determined using the hydrogen evolution technique (an instantaneous measure of fixation rate) in an artificial media trial and the 15N natural abundance technique (an integral measure of fixation) in a soil based trial.
(1100327), F. M. AMIRUL ISLAM. "The macro-scale influence of climate on crop production in the Fitzroy catchment of Central Queensland." Thesis, 1996. https://figshare.com/articles/thesis/The_macro-scale_influence_of_climate_on_crop_production_in_the_Fitzroy_catchment_of_Central_Queensland/19930196.
Full textClimate is the most significant factor in determining plant growth and productivity (Buchdahl, 1996). Recent studies with general circulation models suggest that one of the consequences of increase in greenhouse gases may be greater variability in the climate of a region. Given the possibility of increased variations in climatic conditions, it is deemed that the study of the relationship between climate and crop yield would be useful. For a system which is too complex to be explained by the laws of physics, typically, the determination of the relationship is done through multiple regression analysis. The latter approach is adopted in this study.
Yields of four crops - wheat, barley, sunflower, and cotton - are related to minimum, maximum, and average values of rainfall, temperature, and humidity at planting time, flowering time, and harvesting time for the Fitzroy catchment region of Central Queensland. The most significant climatic factors affecting crop yield are identified. Regression models have been developed which are capable of forecasting the variability of crop production in the region due to climatic variations. Consistent genetic trends and use of existing management practices are assumed in such forecasting.
Furthermore, the complex interaction of climate on crop growth is addressed through the application of the statistical tool of path analysis. From the application of stepwise multiple regression analysis techniques, three explanatory variables are identified as important for each of wheat and barley yields and only one variable is identified for each of sunflower and cotton yields. The regression models are discussed in Section 5.3 of Chapter V. By using path analysis it is found that additional variables have indirect influence on wheat and barley yields. Multiple regression analysis could not identify these variables, which are significant but in an indirect way. The path diagram models are discussed in Section 5.4 of Chapter V. Path analysis allowed us to explore the existence of important variables with indirect influence, and the technique provided us with greater information in predicting changes in yields from the vagaries of climate than is ordinarily available from econometric and regression models.
(9876824), L. John. "Development of a novel harvester for grass seeds and cereal crops." Thesis, 1996. https://figshare.com/articles/thesis/Development_of_a_novel_harvester_for_grass_seeds_and_cereal_crops/13430048.
Full text(9826022), Lance Pendergast. "Benefits of aeration of subsurface drip irrigation water: Field evidence on CQ highlands vertosols." Thesis, 2011. https://figshare.com/articles/thesis/Benefits_of_aeration_of_subsurface_drip_irrigation_water_Field_evidence_on_CQ_highlands_vertosols/13463510.
Full text(9823514), Stephen Ockerby. "Leaves shed light on flowering: (Vegetative growth and control of floral induction in Sorghum bicolor)." Thesis, 2001. https://figshare.com/articles/thesis/Leaves_shed_light_on_flowering_Vegetative_growth_and_control_of_floral_induction_in_Sorghum_bicolor_/13465283.
Full textKaur, Arvinder. "The effects of production techniques on the yield and quality of some leafy vegetables." Thesis, 1997. https://vuir.vu.edu.au/15382/.
Full text(9829109), Donna Rayner. "Spiders in central Queensland mango orchards: Diversity, diel activity and impact of pesticides." Thesis, 2000. https://figshare.com/articles/thesis/Spiders_in_central_Queensland_mango_orchards_Diversity_diel_activity_and_impact_of_pesticides/13424552.
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