Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 115-135). Also available on the World Wide Web.

Thesis (MScAgric)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: The understanding of pear branching and bearing habits is required to optimise management practices. The objective of this study was to quantify the branching and bearing habits of pear cultivars under South African conditions of sub-optimal winter chilling. Two-year-old branches of Pyrus communis L. were classified into groups according to the proleptic (from dormant buds) branching habit. In Winter 1998 upright and flat, two-year-old branches were randomly sampled from trees of seven pear cultivars, i.e., Forelle (on Quince A and BPI rootstocks), Abaté Fetel, Flamingo, Packham's Triumph, Golden Russet Bose, Rosemarie and Beurre D'Anjou (all on BPI rootstock). Laterals were classified according to length « lem, 1-5cm, 5-20cm and >20 cm) and position (distal to proximal quadrants on the two-year-old axis). The number of shoots per cm of quadrant length, per length class for each cultivar was subjected to a cluster analysis, then a canonical and a stepwise discriminant analysis. The cultivars were grouped into four groups from Group 1 (Flamingo) which resembles a spurred growth habit with strong apical control, to Group 4 (Packham's Triumph and Golden Russet Bose) which resembles a spreading growth habit and weak apical control. The bearing habits of the same pear cultivars were quantified. In Winter 1998 ten unpruned branches were tagged on trees of each of the seven cultivars. The description started with the development of the main fruiting branch, forming several leaves in the first year of growth (designated year Y), with meristems developing in the leafaxils. In the following season (year Y+1), these axillary meristems have five alternatives: to remain as a latent bud (L), to develop as a vegetative bud (V), to become a flower bud not setting fruit (F), to become a flower bud producing a fruit (P) or to abort and leave a scar (S). Each year the development of these axillary buds were observed and classified anew, giving rise to a sequence. Between 50% ('Forelle/QA') and 75% ('Rosemarie') of buds remained in the growing phase (comprising of V, F or P buds) during the years of monitoring. It was shown that the predominant bud state in the growing phase was V. Although flower formation was low for all cultivars throughout the trial period, 'Packham's Triumph' and 'Rosemarie' displayed a relatively high proportion ofF and P buds in year Y+1. The latter two cultivars also displayed the bourse-over-bourse bearing phenomenon (PP), producing flowers and fruit terminally on bourse shoots. Artificial extinction of reproductive buds was applied in Winter 1999 to individual branches of the pear cultivar Doyenne du Cornice. This pear variety bears on spurs and is prone to biennial bearing. The objective was to reduce the number of growing buds, thereby increasing the allocation of assimilates to remaining reproductive structures. Three thinning intensities, i.e. 0%, 33% and 66% removal of reproductive buds and two methods, i.e. removal of proximal reproductive buds and removal of reproductive buds situated distally on spurs (by means of cutting back) were utilised. Autonomy of fruiting structures was not enhanced, but results warrant the repetition of this trial using whole trees as experimental units. / AFRIKAANSE OPSOMMING: Dit is belangrik om die vertakkings- en drawyses van pere te verstaan, aangesien bestuurspraktyke hierdeur bepaal word. Die doel van hierdie studie was om die vertakkings- en drawyses van pere onder Suid-Afrikaanse toestande van sub-optimale winterkoue te kwantifiseer. Tweejaar-oue Pyrus communis L. takke is volgens hul proleptiese (vanuit dormante knoppe) vertakkingswyse in groepe geklassifiseer. Regop en plat takke van die peerkultivars Forelle (op Kweper A and BPI onderstamme), Abaté Fetel, Flamingo, Packham's Triumph, Golden Russet Bose, Rosemarie en Beurre D'Anjou (almalop BPI onderstam) is in die winter van 1998 gemonster. Jaarlote is volgens lengte « l cm, 1-5cm, 5-20cm and >20 cm) en posisie (distale tot proksimale kwadrante op die tweejaar-oue draer) geklassifiseer. Die getal lote per cm, per lengte klas per kwadrant vir elke kultivar is toe onderwerp aan 'n groep analise en daarna aan 'n kanoniese en 'n stapsgewyse diskriminant analise. Kultivars is in vier groepe gegroepeer vanaf Groep 1 (Flamingo) wat 'n spooragtige vertakkingswyse en sterk apikale kontrole toon, tot Groep 4 (Packham's Triumph en Golden Russet Bose) met 'n spreidende vertakkingswyse en swak apikale kontrole. Bogenoemde peerkultivars is ook gebruik vir die kwantifisering van drawyses. In die winter van 1998 is tien ongesnoeide takke per boom gemerk. Die beskrywing van die drawyses het begin met die ontwikkeling van die hoof tak van die dra-eenheid. In die eerste jaar van groei (genoem jaar Y) ontwikkel meristeme in die blaar oksels. In die daaropvolgende seisoen (jaar Y+1) is daar vyf ontwikkelings moontlikhede vir die oksellêre knoppe: om latent te bly (L), om vegetatief te ontwikkel (V), om te blom sonder die set van 'n vrug (F), om te blom en 'n vrug te set (P) of om te aborteer en 'n letsel te los (S). Die ontwikkeling van hierdie oksellêre knoppe is elke jaar gemonitor en opnuut geklassifiseer om sodoende 'n reeks te vorm. Gedurende die moniteringstydperk het tussen 50% ('ForelleIKweper A') en 75% ('Rosemarie') van die knoppe in die groeifase (G) (bevattende V, F ofP knoppe) gebly. Die proporsie knop tipes per jaar vir die onderskeie kultivars het getoon dat die oorheersende knop tipe in die G-fase V-knoppe is. Alhoewel blom inisiasie laag was gedurende die hele proeftydperk, het 'Packham's Triumph' en 'Rosemarie' relatiefhoë verhoudings F en P knoppe in jaar Y+1 getoon, wat gepaard gaan met dié kultivars se vermoë om vrugte op een jaar-oue lote te dra. Die beurs-oor-beurs verskynsel (PP) het ook by dié twee kultivars voorgekom. Reproduktiewe knoppe van die peerkultivar Doyenne du Comice is in die winter van 1999 verwyder (kunsmatige abortering) vanaf indivuduele takke. Hierdie peerkultivar dra op spore en is geneig tot alternatiewe drag. Die doel was om die hoeveelheid groeiposisies te verminder en sodoende die allokasie van reserwe assimilate na oorblywende reproduktiewe strukture te verhoog. Drie uitdun intensiteite (0%,33% en 66% van reproduktiewe knoppe verwyder) en twee metodes (verwydering van proksimale spoorknoppe en verwydering van distale spoorknoppe) is gebruik. Outonomiteit van reproduktiewe strukture was nie verhoog nie, maar resultate regverdig die herhaling van dié eksperiment. Daar word aanbeveel dat volledige bome dan as eksperimentele eenhede gebruik word.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Thinning is an important practice in pome fruit production which aims to ensure an optimal yield of high quality, large sized fruit as well as an adequate return bloom. In South Africa, pome fruit thinning is generally done by means of chemicals, with follow-up hand thinning. When thinning is effective, set and thus the hand thinning requirement should be reduced. This is important as labor cost associated with hand thinning is high and continually rising. Chemical thinning is weather dependent and can be environmentally harmful, which has led to a shift towards environmentally acceptable methods of thinning such as mechanical thinning. From 2013 until 2015 the mechanical string thinners, viz. Darwin 300™, BAUM, and Bloom Bandit™, were evaluated. These machines are used to thin trees during full bloom and reduce the number of flowers before fruit set. The aim of the trials was to reduce fruit set and therefore hand thinning requirement, while increasing fruit size and quality, maintaining yield and return bloom. A range of tractor speeds and rotational rates were evaluated with the Darwin 300™ on ‘Forelle’ pears and ‘Cripps’ Pink’ apples, while the BAUM was evaluated only on ‘Cripps’ Pink’ apples. The hand-held Bloom Bandit™ was evaluated on ‘Forelle’, ‘Cripps’ Pink’, ‘Fuji’ and ‘Cripps’ Red’. The tractor-driven mechanical thinning devices gave erratic results. The most consistent results on ‘Forelle’ were obtained using the Darwin 300™ at 5.2 km·h-1 and 300 rpm, while the BAUM gave no consistent results. The unreliability of results were due to South African pome fruit orchards currently being unsuitable for tractor-driven mechanical thinning machines. The ‘Forelle’ orchard trained to a Palmette system was the most suited for thinning, which is reflected in the more positive results obtained, but further improvements are possible. The Bloom Bandit™ effectively thinned pear and apple trees and increased fruit size without a decrease in yield or return bloom. More time is spent on thinning with the device compared to tractor-driven machines and this should be taken into account when considering using the Bloom Bandit™. Thinning intensities of 25%, 50% and 75% of clusters or flowers was applied to mature ‘Forelle’ and ‘Cripps’ Red’ trees during full bloom. Variable effects were seen on fruit set, yield was reduced to acceptable levels, while fruit size was improved in ‘Forelle’ but not ‘Cripps’ Red’. Results showed that when thinning mechanically, the aim should be to remove between 25% and 50% of flowers clusters in ‘Forelle’ and 50% of flowers clusters in ‘Cripps’ Red’. These levels of thinning gave the best results in terms of the remaining hand thinning requirements and improved return bloom in ‘Forelle’. We, however, only evaluated full cluster thinning and not within cluster thinning, which might also occur during mechanical thinning. / AFRIKAANSE OPSOMMING: Vruguitdunning is 'n belangrike praktyk in kernvrugproduksie en het ten doel om voldoende opbrengs van hoë kwaliteit, groot vrugte en voldoende opvolgblom te lewer. In Suid-Afrika, word kernvrugte gewoonlik chemies uitgedun, opgevolg met handuitdunning. Effektiewe uitdunning verminder set en dus die benodigde handuitdunning. Dit is belangrik aangesien die arbeidskoste verbonde aan die handuitdunning hoog is en voortdurend styg. Chemiese uitdunning is afhanklik van weerstoestande en dit kan ook omgewing-onvriendelik wees. Hierdie nadele het gelei tot 'n verskuiwing na omgewingsaanvaarbare metodes van uitdunning soos meganiese uitdun. Vanaf 2013 tot 2015 is die meganiese Darwin 300™, BAUM en Bloom Bandit™ uitdunmasjiene geëvalueer. Hierdie masjiene word gedurende volblom gebruik om blomme uit te dun en verminder die aantal blomme voor vrugset. Die doel van die proewe was om vrugset en dus die handuitdunvereiste te verminder met ‘n gepaardgaande verbetering in vruggrootte en kwaliteit sonder om opbrengs en opvolgblom nadelig te beïnvloed. Trekker en rotasiespoed is gevarieer met die Darwin 300 ™ op 'Forelle' pere en ‘Cripps’ Pink' appels, terwyl die BAUM net op 'Cripps' Pink' appels geëvalueer is. Daarbenewens was die hand-draagbare Bloom Bandit™ geëvalueer op 'Forelle', 'Cripps' Pink’, ‘Fuji’ en ‘Cripps' Red’. Die trekkergedrewe uitdunmasjiene het wisselvallige resultate opgelewer. Die mees konstante resultate op 'Forelle' is verkry met die Darwin 300™ teen 5.2 km·h-1 en 300 rpm, terwyl die BAUM nie konsekwente resultate gegee het nie. Die wisselvallige resultate van die Darwin 300™ en die BAUM is te wyte aan die boorde wat nie vir trekkergedrewe uidunmasjiene geskik is nie. Die 'Forelle’ boord, wat as 'n Palmette stelsel opgelei is, was die meeste geskik vir uitdunning, soos duidelik uit die positiewe resultate wat verkry is, maar verdere verbeterings is steeds moontlik. Die Bloom Bandit™ het peer en appel bome effektief uitgedun deur die handuitdunvereiste te verminder en vruggrootte te verbeter sonder verlies in opbrengs of opvolgblom. Meer tyd word gespandeer tydens uitdunning met hierdie toestel in vergelyking met trekkergedrewe masjiene, en dit moet in ag geneem word met oorweging van die Bloom Bandit™. Uitdunningsintensiteite van 25%, 50% en 75% van die trosse of blomme is tydens volblom toegepas op volwasse 'Forelle’ en ‘Cripps’ Red' bome. Vrugset het aansienlike variasie getoon terwyl opbrengs tot aanvaarbare vlakke verminder en vruggrootte verbeter is in 'Forelle' maar nie in 'Cripps' Red’ nie. Resultate het getoon dat die doel moet wees om tussen 25% en 50% van alle blomme in trosse in 'Forelle’ en 50% van blomme in trosse in 'Cripps’ Red’ tydens meganiese uitdunnig te verwyder. Hierdie vlakke van uitdunning het die beste resultate gegee ten opsigte van die oorblywende handuitdunvereistes en het opvolgblom in 'Forelle’ verbeter. Ons het egter net volledige trosse uitdunning gedoen en nie blomuitdunning binne die tros wat ook tydens meganiese uitdun kan plaasvind nie.

MSCPNT / Department of Food Science and Technology / The study aimed to determine the physicochemical properties, extract and characterise pectin from three varieties (green, purple and orange) of prickly pear (Opuntia spp) fruit peel. Research samples were collected from Bothlokwa Mphakane village in Limpopo province of South Africa. The experimental design for this study was randomized complete block design and each treatment was conducted in triplicate. Pectin was extracted using sulphuric acid at four different pH levels (1, 2, 3 & 4) and microwave power levels (low, medium & high). The characterisation of extracted pectin was done by calculating the ash, moisture, equivalent weight, anhydrouronic acid, methoxyl content, and degree of esterification. Functional groups present in extracted and commercial pectin were investigated for similarities using Fourier Transform Infrared Spectroscopy. The yield of pectin for purple ranged from 2.9% to 13.8%, orange from 1.4% to 9.8% and from 2.3% to 10.0% for green prickly pear peel. A decrease in pH resulted in an increased pectin yield and an increase in microwave power level increased the pectin yield. Maximum yields of 13.8% on purple, 10.0% on green and 9.8% on orange were obtained at pH 1.0 and medium power level. The best condition for extraction using sulphuric acid was at a medium power level and pH 1.0. The pectins obtained were compared against each other in terms of yield, physicochemical characteristics and chemical structure. The ash content of the extracted pectin was significantly higher at 25.16 ± 0.69, 34.26 ± 1.92 and 36.30 ± 1.07, however the pectin showed lower moisture content and equivalent weight. The methoxyl contents were 2.28 ± 0.26, 2.38 ± 0.21 and 3.86 ±0.31, anhydrouronic acid contents were 25.58 ± 2.03, 25.93 ± 2.35 and 38.84 ± 2.29, and degree of esterification were 49.87 ± 0.17, 50.63 ± 4.76 and 56.39 ± 1.60 across the orange, purple and green varieties, respectively. The prickly pear peel pectin spectra exhibited similarities in its absorption pattern to that of commercial citrus pectin. Therefore, the extraction of pectin from prickly pear peels is feasible in viewpoint of yield and quality, and that the pectin has potential for substitution of citrus pectin in the food processing industry. / NRF

Thesis (Msc Food Sc (Food Science))--University of Stellenbosch, 2009. / The aim of this research project was to determine the preference of pear appearance and taste among South African pear consumers using descriptive sensory analysis, consumer preference and physical maturity measurements. The preference of external pear appearance among European consumers was also established. The Agricultural Research Council (ARC) Infruitec-Nietvoorbij, South Africa, aims to breed new cultivars with a local as well as export market potential. They are focused on a range of blushed cultivars from early to late season which do not loose their skin colour. Important eating quality characteristics they are focused on are high sugar content (sweet taste) and a strong pear flavour. Both research studies performed on local South African consumers showed that these objectives align very well with consumer preference. Lightly coloured blushed pears were preferred and important sensory attributes were pear flavour, sweet taste, melt character, juiciness and a soft texture. Sour taste, astringency, mealiness and grittiness were negative attributes. The appearance preference conducted on European consumers determined that these consumers prefer a bright yellow or green colour with a light red or pink blush. Shape played a role and a typical pear shape was preferred. The outcomes of the research performed on local South African consumers were compared to results found internationally. The findings were consistent with important sensory attributes being pear flavour, sweetness and juiciness and yellow or green colours preferred or a light blush was also acceptable. Age and gender did not seem to play a role in the preference analyses. Therefore, preference studies can be conducted locally on new cultivars for the export market. Blushed cultivars are prone to red colour loss in high temperature conditions. Breeding of selections (e.g. ‘Cheeky’) that accumulate more red pigment and are therefore less prone to colour loss has been done to try to overcome this problem. However, these selections are redder and darker in colour and have a lower preference among consumers. A possible solution to this could be to breed light blushed pears (e.g. Rosemarie) but to market the cultivar, as is the case with Cripp’s Pink apples, with separate trademark names for fruit with adequate and inadequate blush development. Thereby, the producers will still receive compensation for their produce if the colour is lost but if not, a higher premium will be received.

Thesis (MScAgric)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: Red colour development on bi-coloured apples and pears ensures better prices for producers. The use of postharvest irradiation to improve colour has been successful on apples, and the objectives of this thesis were to optimise conditions during irradiation for apples and to evaluate the effects of irradiation on pears. 'Cripp's Pink' apples responded to postharvest irradiation with high-pressure sodium (HPS) lights by developing a red blush, whereas the response to irradiation with UV 8 plus incandescent lights was less effective. '8raeburn' apples held at -0.5°C for 4 or 8 weeks prior to irradiation showed a decrease in hue angle and an increase in anthocyanin concentration after 72 hours of irradiation with HPS lamps. In 'Forelle' pears treated in the same way, neither colour development nor anthocyanin synthesis was affected by irradiation. '8raeburn' and 'Cripp's Pink' apples picked weekly for 5 weeks until the optimum harvest date were irradiated with HPS lights. A significant increase in fruit colour was only measured in mature fruit of both cultivars. 'Cripp's Pink' apples were harvested from two production areas with different microclimates, namely, Ceres and Grabouw, and stored for 0, 2 or 5 days at -0.5 °C before irradiation for 120 hours at either 6°C or 20°C. Fruit from Ceres that were irradiated immediately after harvest developed better colour at 6 °C than at 20°C. The differences between fruit irradiated at the two temperatures were no longer significant after 5 days of cold storage prior to irradiation. Fruit from Grabouw consistently developed better colour when irradiated at 6°C than at 20°C. Colour development slightly after 5 days of cold storage prior to irradiation. In another experiment, fruit from both areas were stored at -0.5°C for 20 days before irradiation at either 6°C or 6/20°C. The fluctuating temperature regime resulted in decreases in hue angle of 70° and 65° for the fruit from Grabouw and Ceres, respectively. The decreases were smaller (±200) when fruit were irradiated at 6°C. The hue angle value of well-coloured 'Cripp's Pink' apples held at 3rC under HPS lights for 144 hours increased from 29.3° to 48.3°, and anthocyanin concentration decreased from 739.9 IJg·g·1to 283.6 IJg·g·1. Control fruit held at the same temperature in the dark did not show any change in hue angle value or anthocyanin concentration. 'Bon Rouge' and 'Red d' Anjou', two full red pear cultivars, irradiated with HPS lights for 72 hours, showed no significant changes in hue angle. 'Forelle' pears, harvested with or without attached leaves, were irradiated with HPS at two temperature regimes, 20°C and 200/6°C. The resulting decreases in hue angle were attributed to yellowing and not red colour formation. In conclusion, the response of apples to postharvest irradiation was affected by maturity and temperature, while pears failed to respond at all. / AFRIKAANSE OPSOMMING: Rooikleurontwikkeling van twee-kleur appels en pere verseker beter pryse vir die produsente. Na-oesbestraling om kleur te verbeter is al suksesvol uitgevoer op appels, en die doelwit van hierdie tesis was om die kondisies vir appels gedurende bestraling te optimaliseer en om die effek van bestraling op pere te evalueer. 'Cripp's Pink' appels het reageer op na-oesbestraling met hoëdruk-natriumligte (HDN) deur 'n rooi blos te ontwikkel, terwyl die reaksie op bestraling met UV-B plus gloeilamplig minder effektief was. 'Braebum' appels opgeberg by -O.5aC vir 4 of 8 weke voor bestraling het 'n afname in die kleurskakeringswaarde getoon, asook 'n toename in antosianienkonsentrasie na 72 uur se bestraling met HDN ligte. 'Forelle' pere wat dieselfde behandeling ontvang het, het geen kleurontwikkeling en geen antosianienontwikkeling getoon na bestraling nie. 'Braebum' en 'Cripp's Pink' appels wat weekliks geoes is vir 5 weke tot die optimum oesdatum is bestraal met HDN ligte. Slegs die volwasse vrugte van beide kultivars het 'n betekenisvolle toename in kleur getoon. 'Cripp's Pink' appels is geoes in twee produksie areas met verskillende mikroklimate, naamlik Ceres en Grabouw. Vrugte is opgeberg vir 0, 2 of 5 dae by -O.5aC voor bestraling vir 120 uur by of 6aC of 20aC. Vrugte van Ceres wat onmiddellik na oes bestraal is het beter kleur ontwikkel by 6aC as by 20aC. Kleurontwikkeling by vrugte bestraal by 6 of 20aC het nie verskil wanneer vrugte vooraf opgeberg was by -~5ac vir 5 dae nie. Vrugte van Grabouw het konstant beter kleur pntwikkel wanneer bestraling by 6°C eerder as 20°C plaasgevind het. In die volgende eksperiment, was beide die vrugte van Ceres en Grabouw vir 20 dae opgeberg by -o.soC voor bestraling by 6°C of 6°/20°C. Die flukturerende temperatuur regime het afnames van 70° en 65° in kleurskakeringswaarde getoon vir die vrugte van Grabouw en Ceres, respektiewelik. Die afname was kleiner (±200)wanneer vrugte by 6°C bestraal is. 'Cripp's Pink' appels wat goed gekleur was en opgeberg is by 3rC terwyl dit blootgestel is aan HDN ligte vir 144 uur, het 'n toename van 29.30 tot 48.3° getoon vir die kleurskakeringswaarde, en antosianienkonsentrasie het afgeneem van 739 I'g.g-1 tot 283.6 I1g.g-1. Die kontrole vrugte opgeberg by dieselfde temperatuur in die donker het geen verandering in beide die kleurskakeringswaarde of die antosianienkonsentrasie getoon nie. 'Bon Rouge' en 'Red d' Anjou', twee volrooi peerkultivars, is bestraal met HDN ligte vir 72 uur en het geen betekenisvolle verandering in kleur getoon nie. 'Forelle' pere, geoes met of sonder 'n aangehegte stingelsegment, is bestraal met HDN ligte by twee verskillende temperatuur regimes, nl. 20°C of 20/6°C. Die afname in kleurskakeringswaarde is aan vergeling toegeskryf eerder as aan rooikleurontwikkeling. Ter opsomming, die reaksie van appels op na-oes bestraling is beïnvloed deur rypheid en temperatuur, terwyl pere geen reaksie getoon het nie.

Tyrimai atlikti 2008 m. LŽŪU medelyne įvertinant pirmamečių kriaušaičių, skiepytų į Pyrus pyraster Burgsd. ir Cydonia oblonga Mill. poskiepius, augimo dinamiką ir biometrinius rodiklius. Tirtos pirmamečių kriaušaičių veislės Suvenirs, Kafedralna, Kleboninė, Concorde ir Mramornaja, skiepytos į sėklinį Pyrus pyraster poskiepį ir veislė Kafedralna, skiepyta į Cydonia oblonga poskiepį. Analizuojant bandymą buvo atsižvelgiama į pagrindinius biometrinius skiepų rodiklius: aukštį, kamienėlių skersmenį, skiepų lapų masę ir lapų paviršiaus plotą. Tyrimais nustatyta, kad aukščiausi medeliai užaugo Suvenirs ir Kafedralna veislės, skiepytos į sėklinį Pyrus pyraster poskiepį. Storiausi kamienėliai buvo ΄Mramornaja΄, ΄Kleboninės΄ ir ΄Kafedralna΄ skiepytos į sėklinį Pyrus pyraster poskiepį. Mažiausi ir ploniausi - Kafedralna veislės skiepytos į Cydonia oblonga poskiepį. Intensyvus tirtų kriaušių veislių augimo tarpsnis tęsėsi nuo gegužės mėn. 30 d. iki rugpjūčio mėn. 20 d., o kamienėlių storėjimo – nuo gegužės mėn. 30 d. iki rugsėjo mėn. 10 d. Didžiausią lapų paviršiaus plotą išaugino ΄Mramornaja΄ skiepyta į Pyrus pyraster poskiepį ir veislės Kafedralna skiepyta į Cydonia oblonga poskiepį. Didžiausia lapų masė tarp kriaušaičių, skiepytų į Pyrus pyraster poskiepį, nustatyta Mramornaja ir Kafedralna veislių. / The experiment took place in 2008 in the Lithuania’s University of Agriculture evaluating the dynamic growth of first – year pear – trees on Pyrus pyraster Burgsd. and vegetatyve on Cydonia oblonga Mill. rootstock. The research grafted cv. 'Suvenirs', 'Kafedralna', 'Kleboninė', 'Concorde‘ and 'Mramornaja', grafted on Pyrus pyraster rootstock and 'Kafedralna' on Cydonia oblonga rootstock. While analyzing the attention experiment was paid to their biometrical parameters of grafts highness, stem thickness, leaves’ mass, their surface area. The research showed, that the highest pear - trees were raised from ΄Suvenirs΄ and 'Kafedralna' on Pyrus pyraster rootstock. The thickesst stems were ΄Mramornaja΄,΄Kleboninė΄ and 'Kafedralna' on Pyrus pyraster rootstock. The smallest and the slimmest stems - 'Kafedralna' on Cydonia oblonga rootstock. The most intensive period of investigation of growth continued from May 30 till August 20 th, and the period of stem thickness - from May 30 till September 10 th. The largest surface area of leaves grown ΄Mramornaja΄ on Pyrus pyraster rootstock and 'Kafedralna' on Cydonia oblonga rootstock. The largest leaves’ mass were ΄Mramornaja΄and 'Kafedralna', inoculation into Pyrus pyraster rootstock.

Class of 2009 Abstract / OBJECTIVES: An estimated 26.3 million Americans have Diabetes Mellitus (DM). Currently six classes of agents are approved for the treatments of Type 2 DM. Problems with current options have led to searches for new medications and adjunctive therapy. Prickly pear (Opuntia species) has been traditionally used by Mexicans and Pima Indians for the treatment of DM. This is a retrospective analysis of data obtained from a randomized placebo-controlled prospective experiment in 28 Type 2 DM rodents (ZDF). There were 2 negative control groups which consisted of non-DM rodents and ZDFs; each receiving water. The positive control group consisted of ZDFs who received rosiglitazone 4.75 mg/kg/day. The treatment group consisted of ZDFs who received 5-10 mL/kg/dose of Opuntia ficus indica (Jugo De Nopal) liquid, given twice daily. Weight, blood glucose and platelet aggregation were recorded and analyzed. At baseline, there were no significant differences in weight or blood glucose among ZDF groups. The lean control rodents had significantly lower blood glucose compared to the ZDF rodents (p<0.001). Treatment with Jugo de Nopal resulted in a statistically significant reduction in blood glucose (p<0.001), with a mean decrease in blood glucose of 7%. All treatment groups demonstrated a significant weight gain, however, the prickly pear group had significantly less weight gain than the rosiglitazone group (p=0.028). CONCLUSIONS: There was not a significant difference among the treatment groups with regard to platelet responsiveness. Further studies are necessary to determine the efficacy of prickly pear as a blood glucose lowering agent.

Experiment Station Road is an original work of fiction serving as a collection of short stories set in Hayford, Oregon and Las Vegas in 1962-1972. Each story presents the point of view of a resident in Hayford. The stories are written to function independently, but when read as a collection present insight to cultural diversity, intricate relationships and the ignorance of prejudice.

This thesis addressed the potential of endemic predaceous and parasitic arthropods of the Hood River Valley, Oregon to suppress the pear psylla, Cacopsylla pyricola F8rster. Natural enemies adequately suppressed psylla in three of seven unsprayed orchards of differing vegetational settings, orchard age, and size. Relatively few psylla natural enemies dispersed to unsprayed pear mini-orchards, dspite abundant populations on surrounding noncultivated vegetation. Pear psylla natural enemies were more abundant on arboreal rather than herbaceous non-pear hosts. Selective programs of pear pest control based on diflubenzuron were moderately successful in controlling the pear psylla, with natural enemies aiding in suppression in six of fourteen commercial trials of selective programs. In both unsprayed and commercial pear orchards, late-season psylla densities appeared to be best suppressed when levels of natural enemies were high during early-season. Classification analysis confirmed that orchard site, chemical regime, type (mini- or commercial), and season affected proportions of natural enemies and their pear psylla prey. Complexes of natural enemies and pear psylla immatures from commercial orchards where biological control was successfully demonstrated were taxonomically similar. Effective natural enemy complexes in commercial orchards were characterized by earwigs, lacewing larvae, and moderate proportions of pear psylla immatures during early season and Deraeocoris brevis, earwigs, and lacewings during mid-season. Plagiognathous guttatipes (Uhler) or Diaphnocoris provancheri (Burque) dominated effective natural enemy seasonal complexes at each of two mini-orchards. The functional response to pear psylla eggs was measured for five predaceous mirids. Functional response parameters differed among species and their life-stages, but all destroyed large numbers of psylla eggs. Further experimental directions for the implementation of pear psylla biological control are proposed. General investigative strategies include: (1) augment natural enemies on non-pear vegetation adjacent to the target orchard, and (2) modify the orchard habitat to both encourage natural enemy colonization and allow permanent complexes of natural enemies to develop. Specific tactics include: plant hedgerows of filbert or willow, cultivate snakeflies, introduce Anthocoris nemoralis, adjust early season psylla densities with suitable timing and kind of delayed dormant sprays, using a more effective selective psyllacide, and reduce winter pruning to allow development of natural enemies which overwinter in the egg stage. / Graduation date: 1992