No description available.

Thesis (Ph. D.)--University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 1999. / Includes bibliographical references (leaves 190-211).

Bibliography: leaves 190-211. / xvi, 211 leaves, [24] leaves of plates : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Research was carried out to evaluate pollination efficiency, gene flow by pollen and fruit set in Packham Triumph cultivar pear trees located in a mixed planting of pear cultivars in a commercial orchard in the Coromandel Valley region of South Australia. / Thesis (Ph.D.)--University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 1999

Bibliography: leaves 190-211. Research was carried out to evaluate pollination efficiency, gene flow by pollen and fruit set in Packham Triumph cultivar pear trees located in a mixed planting of pear cultivars in a commercial orchard in the Coromandel Valley region of South Australia.

No description available.

Treatise (D.M.A.) -- Florida State University, 2004. / Advisor: Douglas Fisher, Florida State University, School of Music. Title and description from treatise home page (viewed 9-24-04). Document formatted into pages; contains 193 pages. Includes biographical sketch. Includes bibliographical references.

Thesis (M.Inst.Agrar.)(Microbiology)--University of Pretoria, 2005. / Title from opening screen (viewed March 20, 2006). Includes summary. Includes bibliographical references.

Thesis (MScAgric)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Maintaining constant high yields in „Abate Fetel‟ and „Forelle‟ orchards in South Africa is challenging. Improving productivity in these orchards could be achieved by increasing fruit set and fruit size. Fruit size is an important marketing and quality parameter and has a significant effect on the economic value of fruit. Various protocols to improve fruit set are used by South African producers but these are not well researched. We therefore evaluated different combinations of plant growth regulators including gibberellic acid (GA3), gibberellins 4+7 (GA4+7), GA4+7 combined with 6-benzyladenine (6-BA), aminoethoxyvinylglycine (AVG) and prohexadione-calcium (P-Ca) in combination with trunk girdling during flowering on „Forelle‟ and „Abate Fetel‟ to determine the best fruit set strategy. All applied growth regulators improved fruit set relative to an untreated control over two consecutive seasons, but GA3 and P-Ca reduced return bloom and AVG resulted in smaller fruit size relative to the other treatments. The application of synthetic cytokinins are believed to enhance fruit size by stimulating and extending the cell division period in fruit when applied at the correct stage of fruit growth. In addition, combination of P-Ca with GA4+7 was used successfully on Japanese pear (Pyrus pyrifolia Nakai) and „Bing‟ sweet cherry to improve fruit size. This combination of GA4+7 and P-Ca was evaluated and combined with 6-BA treatments on European pear (Pyrus communis L.) cultivars, Forelle and Abate Fetel, to see if a similar effect on fruit size could be achieved under South African growing conditions. On both „Forelle‟ and „Abate Fetel‟ the combination of GA4+7 and P-Ca increased fruit size, but was more pronounced in „Abate Fetel‟. Growth regulators N-phenyl-N‟ -1,2,3-thiadiazol-5-ylurea (TDZ), N (2-chloro-4-pyridyl)-N‟ -phenylurea (CPPU), 6-BA and 2,4-dichlorophenoxyacetic acid (2,4-D) successfully increased fruit size in pear cultivars Coscia and Spadona in Israel. These growth regulators were applied to „Forelle‟ and „Abate Fetel‟ to determine if a similar effect could be achieved. None of the synthetic cytokinins applied had a significant effect on increasing fruit size in these two cultivars over two consecutive seasons although 6-BA increased return bloom and 2,4-D application resulted in increased fruit set. The stage when the cell division period in „Forelle‟ and „Abate Fetel‟ ends was also determined as 34 and 45 days after full bloom respectively, which can be used in the future to better plan the timing of fruit size enhancement treatments. Based on results from various fruit set and fruit size improvement trials, it can be recommended to use GA4+7 or AVG to increase fruit set on „Forelle‟ and „Abate Fetel‟, depending on the fruit set history of the orchard. Results from fruit size improvement trials were variable, and emphasises the fact that a balance between yield and fruit size must be determined for an orchard to achieve good fruit size and maximum return. / AFRIKAANSE OPSOMMING: Die handhawing van konstante, hoë opbrengste in „Abate Fetel‟ en „Forelle‟ boorde in Suid-Afrika is 'n uitdaging. Produktiwiteit in hierdie boorde kan verhoog word deur vrugset en vruggrootte te verbeter. Vruggrootte is 'n belangrike bemarkings- en kwaliteitsparameter en het 'n betekenisvolle effek op die ekonomiese waarde van vrugte. 'n Verskeidenheid protokolle om vrugset te verbeter word deur Suid-Afrikaanse produsente gevolg, maar hierdie protokolle is nog nie goed nagevors nie. Verskillende kombinasies van plantgroeireguleerders insluitend gibberelliensuur (GA3), gibberellien 4+7 (GA4+7), GA4+7 in kombinasie met 6-bensieladenien (6-BA), aminoetoksievinielglisien (AVG) en prohexadioon-kalsium (P-Ca) in kombinasie met stamringelering is aan „Forelle‟ en „Abate Fetel‟ bome gedurende blomtyd toegedien om die beste vrugsetstrategie te bepaal. Alle plantgroeireguleerdes wat toegedien is het vrugset verbeter relatief tot 'n onbehandelde kontrole oor twee opeenvolgende seisoene, maar GA3 en P-Ca het die aantal blomme in die daaropvolgende seisoen verlaag en AVG het kleiner vruggrootte gelewer relatief tot alle ander behandelings. Dit is wel bekend dat die toediening van sintetiese sitokiniene vruggrootte verbeter deur die stimulering en bevordering van seldeling in vrugte wanneer dit in die regte groeifase toegedien word. Die kombinasie van P-Ca en GA4+7 was suksesvol om vruggrootte te verbeter toe dit aan Japanese pere (Pyrus pyrifolia Nakai) en „Bing‟ kersies toegedien is. Hierdie kombinasie van GA4+7 en P-Ca is geëvalueer en gekombineer met 6-BA-behandelings op die Europese peer (Pyrus communis L.) kultivars, Forelle en Abate Fetel, om te bepaal of dieselfde effek op vruggrootte bereik kan word onder Suid-Afrikaanse groei kondisies. Op beide „Forelle‟ en „Abate Fetel‟ het die kombinasies van GA4+7 en P-Ca vruggrootte verbeter, maar dit was meer opmerklik in die geval van „Abate Fetel‟. Die groeireguleerders N-feniel-N‟ -1,2,3-thiadiazol-5-ylurea (TDZ), N (2-chloro-4-piridiel)-N‟ -fenielurea (CPPU), 6-BA en 2,4- dichloorfenoksieasynsuur (2,4-D) het vruggrootte verbeter in „Coscia‟ en „Spadona‟ pere in Israel. Hierdie plantgroeireguleerders is toegedien aan „Forelle‟ en „Abate Fetel‟ om vas te stel of dieselfde effek verkry kon word. Nie enige van die sintetiese sitokiniene wat toegedien is het 'n betekenisvolle effek op die verbetering van vruggrootte in hierdie twee kultivars oor twee opeenvolgende seisoene getoon nie, alhoewel 6-BA die verbetering van blom in die daaropvolgende seisoen tot gevolg gehad en 2,4-D vrugset verbeter het. Die stadium waar seldeling in „Forelle‟ en „Abate Fetel‟ eindig is vasgestel as 34 en 45 dae na volblom, onderskeidelik, wat in die toekoms gebruik kan word om die beplanning en tydsberekening van vruggrootte behandelings te verbeter. Na verskeie vrugset en vruggroote verbeterings proewe, kan aanbeveel word dat GA4+7 of AVG gebruik kan word om vrugset in „Forelle‟ en „Abate Fetel‟ te verbeter, afhangende van die vrugset geskiedenis van die boord. Resultate van vruggrootte verbeterings proewe het gevarieër en beklemtoon net weer die feit dat 'n balans tussen opbrengs en vruggrootte bepaal moet word om optimale vruggrootte te handhaaf en so hoë winste te verseker. / SAAPPA

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Our study aimed to determine the preference of Western Cape consumers for the eating quality and appearance of pears. Identifying the main sensory drivers of liking and consumer groupings with similar preferences may allow the pear industry to target specific markets and increase local consumption, which is stagnating at relatively low levels. Our first trial included 9 European pear cultivars (Pyrus communis L.) and one Asian pear cultivar (P. pyrifolia (Burm.) Nak.). These were chosen to represent a wide range of characteristics in order to identify the main sensory drivers of liking and possible consumer groupings. The majority of the 421 consumers, irrespective of gender, ethnicity and age, preferred pears with a distinct pear flavour, a sweet taste, a fair amount of malic acid, soft, juicy flesh with melt character, and a yellow or pale green peel colour with a typical pear shape. Astringency, sourness and grittiness negatively affected consumer preference. None of the pears were mealy and therefore we could not assess this characteristic. Two consumer clusters with similar preferences for eating quality and also for appearance were identified. In terms of eating quality, group 1 (55% of consumers) indicated a liking for a wide range of cultivars with poorly defined likes and dislikes. Group 2 (45% of consumers), in contrast, had a high liking for the eating quality of a small selection of cultivars while disliking the rest. Based on the preferences for appearance, group 1 (61% of consumers) again indicated a liking for a wide range of cultivars. Group 2 (39% of consumers) scored the most familiar cultivars, viz. Bon Chretien and Packham’s Triumph, very high and the other cultivars much lower than group 1. The objective of our second study was to investigate consumer preference for firm, juicy pears compared to soft pears with a melt character and to identify which of ‘Forelle’, ‘Packham’s Triumph’ and ‘Abate Fetel’ is best suited to either option. Pears were harvested within the commercial harvest window (H1) (flesh firmness at 6- 6.8kg, 6.4-7kg and 6-6.8kg respectively) and again a month later (H2). H1 and H2 pears were ripened at room temperature (20 ºC) for seven or one day, respectively. More consumers (67%) correlated positively with melt character, juiciness, overall pear flavour and sweet taste. These characteristics were the most prominent in H1 ‘Packham’s Triumph’ pears while H2 fruit were much firmer, but lower in preferred flavour characteristics. There is, however, also a market for crisp and juicy pears as 33% of the consumers showed a preference for these characteristics. ‘Forelle’ and ‘Abate Fetel’ could both be suitable for this market. ‘Forelle’ was preferred firm, probably because H1 soft pears were more astringent and sour as well as less juicy than H2. There was no difference in preference between H1 and H2 in ‘Abate Fetel’. In conclusion, most Western Cape consumers prefer European pears with the characteristic soft, melting texture, but a third of consumers seem to like firm, juicy pears. Hence, there is opportunity to develop a market for tree-ripe and Asian pears, but marketing will be needed to overcome appearance preferences. / AFRIKAANSE OPSOMMING: Ons studie was daarop gemik om die voorkeur van Wes-Kaap verbruikers vir die eetkwaliteit en voorkoms van pere te bepaal. Die identifisering van die belangrikste sensoriese drywers van smaakvoorkeure en verbruikersgroepe met soortgelyke voorkeure kan die peerbedryf toelaat om spesifieke markte te teiken en plaaslike verbruik te verhoog, wat tans op relatief lae vlakke stagneer. Ons eerste proef het 9 Europese peer kultivars (Pyrus communis L.) en een Asiatiese peer kultivar (P. pyrifolia (Burm.) Nak.) ingesluit. Die kultivars is gekies om 'n wye verskeidenheid eienskappe te verteenwoordig sodat die belangrikste drywers van sensoriese smaakvoorkeure en moontlike verbruikersgroeperings geïdentifiseer kon word. Die meerderheid van die 421 verbruikers, ongeag geslag, etnisiteit en ouderdom, het pere met 'n duidelike peer geur, 'n soet smaak, 'n redelike hoeveelheid appelsuur, sagte en sappige tekstuur met n smeltkarakter, en 'n geel of liggroen skilkleur met 'n tipiese peer vorm verkies. Frankheid, hoë suurvlakke en grinterigheid het verbruikers voorkeur negatief beinvloed. Geen pere in ons studie was melerig nie en daarom kon ons nie hierdie eienskap evalueer nie. Twee verbruikersgroepe met soortgelyke voorkeure vir eetkwaliteit en peervoorkoms is geïdentifiseer. In terme van eetkwaliteit het groep 1 (55% van die verbruikers) voorkeur vir 'n wye verskeidenheid van kultivars aangedui. Groep 2 (45% van die verbruikers) daarteenoor het die eetkwaliteit van net 'n klein seleksie van kultivars verkies, terwyl hul ‘n afkeur getoon het vir die res. In terme van voorkoms, het groep 1 (61% van die verbruikers) weereens van 'n wye verskeidenheid kultivars gehou terwyl groep 2 (39% van die verbruikers) baie hoë punte aan die bekende Bon Chretien en Packham's Triumph kultivars toegeken het, maar die ander kultivars baie laer as groep 1 bepunt het. Die doel van ons tweede proef was om verbruikersvoorkeur vir ferm, sappige pere teenoor sagte pere met 'n smelt tekstuur te bepaal en tot watter mate 'Forelle', 'Packham's Triumph’ en ‘Abate Fetel' geskik is vir iedere opsie. Pere is tydens die kommersiële oesvenster (H1) (fermheid 6-6.8kg, 6.4-7kg en 6-6.8kg onderskeidelik) en weer 'n maand later (H2) geoes. H1 en H2 pere is teen kamertemperatuur (20 ºC) onderskeidelik vir sewe of een dag rypgemaak. Die meeste verbruikers (67%) se voorkeur korreleer positief met 'n smeltende tekstuur, sappigheid, peer geur en soet smaak. Hierdie eienskappe was die prominentste in H1 'Packham’s Triumph' pere terwyl H2 vrugte baie fermer, maar laer in voorkeur geureienskappe was. Daar is egter wel 'n mark vir ferm, sappige pere aangesien 33% van die verbruikers 'n voorkeur toon vir hierdie eienskappe. 'Forelle' en 'Abate Fetel' sou beide geskik kon wees vir hierdie mark. 'Forelle' is verkies as fermer peer, waarskynlik omdat H1 sagte pere meer frank, suurder sowel as minder sappig was. Daar was geen verskil in verbruikersvoorkeur tussen 'Abate Fetel’ se H1 en H2 pere nie. Ten slotte, die meeste verbruikers van die Wes-Kaap verkies die smaak van ryp Europese pere met hul karakteristieke sagte, smeltende tekstuur, maar 'n derde van die verbruikers hou wel van ferm, sappige pere. Daar is dus 'n geleentheid om die mark vir boomryp en Asiatiese pere te ontwikkel, maar bemarking sal nodig wees om die verbruikersvoorkeure vir voorkoms te oorkom.