No description available.

There has been little research into the compatibility of commonly utilized apple rootstocks and VA-fungal types, and even less research regarding the effects of herbicides used in orchards, on the VAM symbiosis of apple trees. Studies demonstrated that early inoculation of young apple plants, prior to transplanting, results in healthy and vigorous plants with better growth and nutrition than uninoculated plants. We studied the efficiency of VA-fungal species and isolates on young apple rootstocks, produced by in vitro propagation. Mycorrhizal inoculation promoted plant growth, dry mass production and leaf P concentration. Mycorrhizal efficiency was associated with larger external hyphal network but showed no relation with the internal colonization. Despite the high P-fertility of the soil used, growth enhancement due to mycorrhizal inoculation was attributed to an improved P nutrition. / In a second experiment, the effect of herbicides currently used in orchards was tested on the mycorrhizal symbiosis. Paraquat, simazine and dichlobenil were applied to soil with mycorrhizal and non-mycorrhizal apple plants. Mycorrhizae increased herbicide toxicity in apple, as demonstrated by the greatly increased plant mortality. While both paraquat and simazine decreased spore germination in vitro, none of the herbicide treatments affected root colonization in soil. Effects on the photosynthetic rate, measured after herbicide application, indicated a physiological interaction between mycorrhizal colonization and dichlobenil, involved in the toxic response of apple plants.

Thesis (Ph. D.) -- University of Western Sydney, Hawkesbury, 2000. / Includes bibliographical references (leaves 160-187).

Thesis (MScAgric)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: In order to study the dormancy of apple buds in conditions of inadequate chilling a number of trails were done during 2000 and 2001. Year-old, unbranched shoots of 'Royal Gala', 'Braeburn', 'Cripps' Pink' and 'Granny Smith' apple were harvested randomly from bearing commercial orchards in the Koue Bokkeveld [33°S, 945m, ca.1300 Utah model chili units (CU)) and Elgin (34 "S, 305m, ca.750CU) regions of the Western Cape, South Africa, respectively. Shoots were chilled at 5-rC. Two replicate bundles were removed from the cold room, prepared and forced at 25°C with continuous illumination until budburst had occurred on at least 25% of the shoots per bundle. The change in the rate of budburst over time was calculated for each orchard and to this response; either a linear or a quadratic function was fitted. Poorly correlated variables were selected that best describe these functions. Using these variables, the orchards were separated into cluster groupings that represented a dormancy pattern. The first split separated the lower chilling requirement cultivars from the higher cultivars. The second and third split separated the orchards according to area differences. The clusters representing the warmer area orchards initially entered deeper into dormancy before exiting. The clusters for the colder area immediately had an increased budburst rate. This data confirm that the chilling requirement includes a period of dormancy induction. An important genotype and environment interaction, other than cold unit accumulation, was observed that could be responsible for terminating bud dormancy. Terminal apple buds from 'Royal Gala' Braeburn', 'Cripps' Pink' and 'Granny Smith' apples were cut from orchards in the Koue Bokkeveld and Elgin regions of the Western Cape, South Africa. Buds were harvested every two weeks during the dormant period. The buds were cut in half and leaf scales removed before the water potential were measured. Fresh and dry weights of the buds were also determined. The data presented confirms the changes in availability of free water in dormant buds and that it could be measured in this way. A definite influence of temperature was illustrated. The water potential from buds in a cold production area (Koue Bokkeveld) behaved more "normally" - water is in a bound form during most of the winter and change to an available form later in winter - whereas buds from a warmer production area did not change much in water potential or content. In the trial, two-year-old proleptic-branched shoots, ca. 500mm long, were selected from a 'Royal Gala' orchard in the Koue Bokkeveld region in the Western Cape, South Africa. During the dormancy period of 2000, shoots received two cold treatments; chilling in a cold room at 5-7°C and the natural chilling received in the field. In 2001, the trail was repeated, but only with the field chilling. The shoots received five dormant pruning treatments: control (not pruned), pruning back to the fourth lateral (heading) before or after chilling; and removal of the 2nd and 3rd laterals (thinning) before or after chilling. After pruning and chilling treatments, the shoots were removed from the orchard or cold room every two weeks and forced in a growth chamber. The rate of bud burst (1/days to 50% bud burst) was calculated for the terminal buds of the lateral shoots. Laterals were categorisation according to position: the terminal extension shoot, the 4th lateral, and all other laterals were pooled. Removing distal tissue by pruning (heading more than thinning) promoted bud burst on laterals. Pruning before chilling was more effective than after chilling. The correlative phenomena that inhibit bud burst on proximal shoots within two-yearold branches were manipulated by pruning. The branching response of one-year-old unbranched shoots, 0.5m long, from 'Royal Gala' and 'Cripps' Pink' apple and 'Rosemary' pear were studied after physical manipulation treatments. Shoots for treatment a to d were re-orientated from either a horizontal or vertical position or left in the original position as control, treatment e to h involved the same re-orientation of shoots and were headed. The amount of growth (in mm) from each node was recorded as well as the position from the terminal bud. The 'Cripps' Pink' had a definite shift in the acrotonic branching pattern (for headed and unheaded), towards a more basitonic response. The reduced effect on 'Royal Gala' and 'Rosemary' suggest a difference in genotype response to the treatments as well as time of treatment. / AFRIKAANSE OPSOMMING: Ter wille van die navorsing oor die invloed van gebrekige koue op dormansie van apple knoppe en die gepaardgaande probleme is 'n reeks proewe gedoen gedurende 2000 en 2001. Jaar oue onvertakte lote van 'Royal Gala', 'Braeburn' , 'Cripps' Pink' en 'Granny Smith' appels is ewekansig geoes vanaf komersieële boorde in die Koue Bokkeveld [33°S, 945m, ca.1300 Utah koue eenhede (CU)] en Elgin (34°S, 305m, ca.750CU) omgewings van die Wes Kaap , Suid Afrika. Die lote is daarna verkoel gehou by 5- 7°C. Lote is elke twee weke vanuit die koue kamer geneem en geforseer met 25°C en deurlopend belig. Die aantal knoppe wat groenpunt bereik het is genoteer totdat 25% van die lote begin bot. Die verandering oor tyd vir elke boord is bereken en 'n liniëre of kwadratiese funksie is daarop gepas. Swak gekorreleerde waardes is gekies wat die funksies die beste beskryf. D.m.v hierdie die waardes is die boorde in groepe ingedeel wat 'n dormansie patroon verteenwoordig. Na die eerste vedeeling is die hoë en lae koue behoefte kultivars geskei. In opvolgende verdelings is die boorde verder in die twee areas geskei met elk 'n spesifieke dormansie patroon. Die groepe wat die warmer area se boorde bevat het aanvanklik dieper in dormansie in beweeg voor dit 'n styging in groei potensiaal getoon het. Die groepe vanaf die kouer produksie area het onmiddelik 'n verhooging in bot tempo getoon. Die data bevestig dat 'n koue behoefte 'n periode van dormansie induksie insluit. 'n Belangrike kultivaromgewing- interaksie, ten spyte van koue eenhede akkumulasie, is waargeneem wat verantwoordlik kan wees vir beëindiging van dormansie. Om die verandering van water status in dormante appel knoppe te bestudeer, was die volgende proef uitgevoer. Terminale apple knoppe van dieselfde vier kultivars en vanaf die selfde twee areas in die Wes Kaap as bogenoemde, is elke tweede week gedurende die winter 2001 gesny vanaf komersieële boorde. Daarna is die knoppe middel deur gesny en die skudblare verwyder voor die vars massa gemeet en daarna die waterpotensiaal bepaal is. Die data het bevestig dat daar veranderings in beskikbaarheid van vry water in dormante knoppe gedurende dormansie plaasvind. 'n Definitiewe invloed van temperatuur op waterpotensiaal is geïllustreer. Die waterpotensiaal van knoppe in die kouer produksie area toon 'n meer normale respons (gedurende die winter is die water in 'n gebonde vorm, wat later in die winter na vry water verander). Daar teenoor is daar in die knoppe van die warm produksie area nie veel verandering in waterpotensiaal of water massa getoon nie. Gedurende die winter van 2000 is twee jaar oue proleptiese vertakte 'Royal Gala' lote, ongeveer 500mm lank, gekies vanaf 'n boord in die Koue Bokkeveld. Die lote is verdeel en het twee koue behandelings ontvang. Koue kamer by 5-T'C en natuurlike koue in die boord. In 2001 is net die natuurlike koue behandeling herhaal. Daar is vyf dormante snoei behandeling op die lote gedoen; kontrole (geen), snoei terug tot die vierde lateraal voor en na die koue; verwydering van die 2de en 3de laterale voor en na koue. Na koue en snoei is die lote verwyder en in die groeikamer geforseer by 25°C en met konstante illuminasie. Die tempo waarteen die laterale gebot het is bereken (1\dae to 50% groen punt) waarna die laterale in klasse gedeel is; terminale knop, die vierde lateraal en die res van die laterale saam. Verwydering van distale weefsel d.m.V. snoei verhoog die tempo waarteen laterale knoppe groenpunt bereik. Snoei voor die koue behandeling was meer effektief as daarna. Die korrelatiewe fenomeen wat bot inhibeer van proksimale lote kan gemanipuleer word in die twee jaar apple loot. Die vertakkings gedrag van een jaar oue onvertakte 'Royal Gala', 'Cripps' Pink' apple en 'Rosemary' peer lote, 0.5m lank, is ondersoek na fisiese manipulasies gedoen is gedurende mid winter 2000. Vir die eerste vier behandelings (a,b,c,d) is die lote in 'n horisontale of vertikale possisie gelos as kontrole, of horisontale of vertikale gebuig en daar gehou d.m.v. binddraad. Behandelings e tot h het dieselfde behels maar die lote is ook nog in die helfte deur gesny (getop). Die hoeveelheid groei in mm vir elke node is aangeteken asook die posisie vanaf die terminale knop. Die 'Cripps' Pink' het 'n definitiewe veskuiwing vanaf 'n akrotoniese na 'n basitoniese vertakkingspatroon getoon. Die reaksies op die manipulasies of die gebrek daaraan ('Royal Gala' en 'Rosemary' ) kan 'n aanduiding wees dat genotipes verskillend reageer op die behandelings asook op die tyd wat dit gedoen was.

Thesis (MScAgric)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: We aimed to determine how canopy microclimate influences fruit quality and consumer preference in apples. Our postulate was that consumer preference would be higher for the taste, but not necessarily for the appearance of outer canopy fruit. Outer canopy fruit, exposed to higher irradiance and temperatures, accumulated more phenolics and ascorbic acid, and had higher antioxidant capacities in their peel compared to inner canopy fruit. Phenolic levels and antioxidant capacity were also higher in the flesh of outer canopy fruit while ascorbic acid was higher in the flesh of outer canopy ‘Granny Smith’. From a marketing perspective, outer canopy fruit can be seen as possessing greater potential health benefits. Outer canopy fruit were higher in dry matter content (DMC), sugars and TSS, but lower in TA in the first season of the study. The sweeter and less sour taste of outer canopy fruit was preferred in all three cultivars over two years of study. Sunburnt fruit were higher in DMC, TSS:TA ratio, lower in TA and were perceived to be the sweetest, least sour and lowest in apple flavour and textural attributes. The effect of canopy position on apple flavour and textural attributes was inconsistent. The redder outer canopy ‘Starking’ fruit were preferred by consumers because this cultivar is marketed with full red colour. The appearance of blushed, outer canopy ‘Granny Smith’ and ‘Golden Delicious’, and sunburnt ‘Golden Delicious’ were not preferred by consumers. Consumers are not familiar with such fruit. Blushed ‘Granny Smith’ is downgraded and sometimes sold at a lower price while sunburnt apples are processed or dumped depending on sunburn severity. The consistency of these results was investigated in one season for ‘Golden Delicious’ from five locations. The consumer taste preference differential for inner and outer canopy fruit diminished as canopy size decreased. This indicates that there generally would be no benefit in harvesting and marketing outer and inner canopy ‘Golden Delicious’ separately. We investigated the effect of familiarity on consumer preference by utilising an “experienced” consumer group of farm labourers from Ceres who are familiar with all fruit on a tree compared to an “inexperienced” consumer group of Stellenbosch consumers who are only exposed to fruit on the commercial market and eat apples less frequently. Both groups preferred the taste and appearance of outer canopy ‘Starking’. The taste of sunburnt fruit was preferred by a substantial segment of both consumer groups, but the appearance was preferred by only some Ceres consumers. A small segment of Ceres consumers preferred the taste and appearance of the blushed outer canopy ‘Granny Smith’ and ‘Golden Delicious’ while some Stellenbosch consumers preferred the taste of outer canopy ‘Golden Delicious’, but not ‘Granny Smith’. Therefore, Ceres consumers who are more familiar with the taste attributes of sunburnt and blushed fruit of green cultivars have a higher preference for the appearance of these fruit. Based on our results, fruit marketers may be able to develop niche markets for outer canopy and sunburnt ‘Golden Delicious’ fruit. / AFRIKAANSE OPSOMMING: Ons het ondersoek hoe vrugkwaliteit en verbruikersvoorkeur in appels deur die blarekoepel mikroklimaat beïnvloed word. Ons vermoede was dat verbruikersvoorkeur hoër sou wees vir die smaak, maar nie noodwendig vir die voorkoms van vrugte aan die buitekant van die boom (buitevrugte) nie. Buitevrugte was blootgestel aan hoër ligstraling en temperature en hul skil het meer fenole en askorbiensuur geakkumuleer asook hoër antioksidantkapasiteit gehad vergeleke met binnevrugte. Fenole en die antioksidantkapasiteit was ook hoër in die vleis van buitevrugte terwyl askorbiensuur hoër was in die vleis van ‘Granny Smith’ buitevrugte. Vanuit bemarkingsperspektief kan buitevrugte gesien word as vrugte met hoër potensiële gesondheidsvoordele. Buitevrugte was hoër in droë materiaal inhoud (DMC), suikers en TSS, maar laer in TA, laasgenoemde slegs in die eerste seisoen van die studie. Verbruikers het die soeter en minder suur smaak van buitevrugte verkies in beide jare van die studie. Vrugte met sonbrand was hoër in DMC, TSS:TA verhouding, laer in TA en was die soetste, minste suur en laagste in appelgeur en tekstuureienskappe. Die effek van blaredakposisie op appelgeur en tekstuureienskappe was variërend. Verbruikers het die rooier buitevrugte van ‘Starking’ verkies. Ons reken dit is omdat hierdie kultivar as ‘n volrooiappel bemark word. Verbruikers het minder van die voorkoms van rooiblos ‘Granny Smith’ en ‘Golden Delicious’ asook van ‘Golden Delicious’ met sonbrand gehou. Verbruikers is nie vertroud met sulke vrugte nie. Rooiblos ‘Granny Smith’ appels word afgradeer en word soms teen laer pryse verkoop terwyl sonbrand appels geprosesseer of uitgeskot word afhangend van die graad van sonbrand. Die konsekwentheid van ons resultate is ondersoek met ‘Golden Delicious’ van vyf lokaliteite. Die smaakvoorkeur differensiaal tussen binne- en buitevrugte het afgeneem met afname in boomgrootte. Oor die algemeen sou daar dus geen voordeel wees om ‘Golden Delicious’ binne- en buitevrugte apart te oes en te bemark nie. Ons het die effek van vertroudheid op verbruikervoorkeur ondersoek deur gebruik te maak van “ervare” verbruikergroep bestaande uit plaasarbeiders in Ceres en “onervare” verbruikersgroep van Stellenbosch. Die Ceres verbruikers is vertroud met al die appels op die boom vergeleke met die Stellenbosch verbruikers wat net blootstelling het aan vrugte op die kommersiële mark en ook minder gereeld appels eet. Beide verbruikersgroepe het die voorkoms en smaak van ‘Starking’ buitevrugte verkies. Substansiële segment van beide verbruikersgroepe het die smaak van sonbrand vrugte verkies, maar die voorkoms van hierdie vrugte is slegs deur sommige Ceres verbruikers verkies. Klein segment Ceres verbruikers het die smaak en voorkoms van ‘Granny Smith’ en ‘Golden Delicious’ buitevrugte verkies terwyl sommige Stellenbosch verbruikers die smaak van ‘Golden Delicious’, maar nie ‘Granny Smith’ buitevrugte verkies het nie. Ceres verbruikers is meer vertroud met die smaakeienskappe van sonbrand en blosvrugte van groen kultivars en het gevolglik hoër voorkeur vir die voorkoms van hierdie vrugte. Gebaseer op ons resultate kan bemarkers moontlik nismark vir gebloste en sonbrand ‘Golden Delicious’ vrugte ontwikkel.

No description available.

M.S.

M.S.

This study was undertaken to determine the effect of different work methods, types of equipment, and the size of operation on the cost of packing apples in bushel units. The information in this study was based on plants packing from 9,000 to 108,000 bushels of apples during the 1956 packing season. The data collected at these plants revealed wide variations in methods of handling and packing apples which had significant influences on the cost of packing house operations. To determine the relative influence of these factors on the cost of packing apples, each of the major packing house operations was considered separately. / Master of Science

Call number: LD2668 .T4 1930 M41