In this thesis, I examined ethnobotanical uses, traditional knowledge and folk classification of moolks, Pacific crabapple (Malus fusca (Raf.) C.K. Schneid.; Rosaceae) for the Gitga’at First Nation of Hartley Bay, and measured morphological variation of sampled trees at the traditional harvesting location. This deciduous tree has historically been an important resource for food, materials and medicine for Indigenous Peoples throughout most of its range along the Pacific coast of North America. One of these groups is the Gitga’at people, whose knowledge is also interesting due to their recognition of approximately five unique varieties. I conducted interviews with seven Gitga’at elders, who recognize up to five distinct varieties moolks, based on fruit characteristics and harvesting location, each with its specific applications. The cultural importance of crabapples was documented through these interviews, as expressed in their folk taxonomy, linguistic knowledge, ethnobotanical uses and management strategies. In addition, I conducted a morphological and ecological study to examine the variability within and among 27 crabapple trees. To determine ecological and morphological variability of crabapples within its traditional harvesting area, I sampled foliage and fruits and measured their traits from individual trees and different sites, and recorded information about the localized habitat. While some fruit and leaf traits are correlated, I identified significant variation within and among trees making it hard to delineate the varieties as described by the elders. In conclusion, by using these two knowledge systems – traditional ecological knowledge and western scientific knowledge – to complement each other, it can result in a more detailed understanding of a botanical species, as they both present us with information about slightly different characteristics. In a rapidly changing world, we need as much collaboration as necessary to allow for resiliency. / Graduate / 0326 / 0309 / arbutus@uvic.ca

A macieira (Malus x domestica Borkh.) é uma frutífera de clima temperado de grande importância econômica, e sua produtividade está diretamente relacionada à dormência. Além dos genes responsáveis pelo controle molecular, uma série de proteínas e metabólitos também é recrutada para proteger a integridade da gema dormente, destacando-se as desidrinas (DHN) e as enzimas galactinol sintases (GolS). As DHNs são proteínas que atuam na resposta adaptativa vegetal a estresses abióticos, enquanto que GolS são enzimas responsáveis pela síntese de galactinol, essencial à síntese de oligossacarídeos da família da rafinose (RFOs), os quais se acumulam em resposta a estresses abióticos. O objetivo do presente trabalho foi explorar a adaptação das gemas a condições de estresse a que são submetidas na dormência, visando identificar genes com potencial uso biotecnológico. Para tal, foram identificados e caracterizados os genes codificadores de DHNs e GolS no genoma da macieira por meio da utilização de ferramentas in silico para estudar a evolução, experimentos a campo e sob condições controladas, análises de expressão, localização subcelular, e geração de plantas transgênicas. As análises evolutivas sugerem que eventos de duplicação do genoma inteiro (WGD) foram responsáveis por moldar a evolução e diversificação dos genes GolS em macieira, enquanto que no caso das DHN eventos de duplicação em tandem e WGD nortearam a sua evolução. Nossos resultados sugerem que DHNs, galactinol e rafinose integram uma série de mecanismos que agem em conjunto durante a dormência a fim de proteger a integridade da gema, além dos carboidratos constituírem uma fonte de energia para a brotação. Ao longo da evolução, o aparecimento de novas estruturas e programas de desenvolvimento, tais como a gema e a dormência, necessitaram de adaptação de vias moleculares já estabelecidas, o que ajuda a explicar por que as dormências de gemas e de sementes compartilham rotas moleculares comuns. Finalmente, o gene MdDHN11 foi funcionalmente caracterizado e nossos resultados fornecem evidências de que MdDHN11 desempenha importantes papéis durante o desenvolvimento da semente de maçã, protegendo o embrião e o endosperma de alterações no status da água. Além disso, apenas a planta superexpressando MdDHN11 sobreviveu ao ensaio de simulação de seca, confirmando o potencial uso biotecnológico de DHNs de macieira no aumento da tolerância ao déficit hídrico. / Apple tree (Malus x domestica Borkh.) is a temperate fruit crop of great economic importance worldwide and its productivity is related to bud dormancy. Besides genes responsible for the molecular control of the process, a number of proteins and metabolites are also recruited to protect bud integrity, such as dehydrins (DHN) and galactinol synthases (GolS). DHNs are proteins that act on plant adaptive responses to abiotic stresses, while GolS are enzymes that catalyze for the synthesis of galactinol, an essential carbohydrate in the synthesis of raffinose family oligosaccharides (RFOs), which also accumulate in response to abiotic stresses. The objective of this work was to explore bud adaptation to stress conditions that occur during dormancy to identify genes with potential biotechnological applications. DHN and GolS genes were identified and characterized in the apple genome employing in silico tools, experiments under field and controlled conditions, expression analysis, subcellular localization assays, and the generation of transgenic plants. Evolutionary analyses suggest that whole genome duplication (WGD) events were responsible for shaping the evolution and diversification of GolS genes in apple, whereas WGD and tandem duplication events could be held accountable for DHN evolution. Our results suggest that DHNs, galactinol and raffinose integrate a series of mechanisms that act together during dormancy in order to protect bud integrity, besides the carbohydrates being an energy source for budbreak. During evolution, the appearance of new structures and developmental programs, such as buds and dormancy, required the adaptation of already established molecular pathways, partially explaining why bud and seed dormancy share common pathways. Finally, the MdDHN11 gene has been functionally characterized and our results provide evidences that MdDHN11 plays important roles during apple seed development by protecting the embryo and the endosperm from water deficit. Moreover, only the plant overexpressing MdDHN11 survived the water withholding assay, confirming the potential biotechnological use of apple DHNs in increasing tolerance to drought.

No description available.

A macieira (Malus x domestica Borkh.) é uma frutífera de clima temperado de grande importância econômica, e sua produtividade está diretamente relacionada à dormência. Além dos genes responsáveis pelo controle molecular, uma série de proteínas e metabólitos também é recrutada para proteger a integridade da gema dormente, destacando-se as desidrinas (DHN) e as enzimas galactinol sintases (GolS). As DHNs são proteínas que atuam na resposta adaptativa vegetal a estresses abióticos, enquanto que GolS são enzimas responsáveis pela síntese de galactinol, essencial à síntese de oligossacarídeos da família da rafinose (RFOs), os quais se acumulam em resposta a estresses abióticos. O objetivo do presente trabalho foi explorar a adaptação das gemas a condições de estresse a que são submetidas na dormência, visando identificar genes com potencial uso biotecnológico. Para tal, foram identificados e caracterizados os genes codificadores de DHNs e GolS no genoma da macieira por meio da utilização de ferramentas in silico para estudar a evolução, experimentos a campo e sob condições controladas, análises de expressão, localização subcelular, e geração de plantas transgênicas. As análises evolutivas sugerem que eventos de duplicação do genoma inteiro (WGD) foram responsáveis por moldar a evolução e diversificação dos genes GolS em macieira, enquanto que no caso das DHN eventos de duplicação em tandem e WGD nortearam a sua evolução. Nossos resultados sugerem que DHNs, galactinol e rafinose integram uma série de mecanismos que agem em conjunto durante a dormência a fim de proteger a integridade da gema, além dos carboidratos constituírem uma fonte de energia para a brotação. Ao longo da evolução, o aparecimento de novas estruturas e programas de desenvolvimento, tais como a gema e a dormência, necessitaram de adaptação de vias moleculares já estabelecidas, o que ajuda a explicar por que as dormências de gemas e de sementes compartilham rotas moleculares comuns. Finalmente, o gene MdDHN11 foi funcionalmente caracterizado e nossos resultados fornecem evidências de que MdDHN11 desempenha importantes papéis durante o desenvolvimento da semente de maçã, protegendo o embrião e o endosperma de alterações no status da água. Além disso, apenas a planta superexpressando MdDHN11 sobreviveu ao ensaio de simulação de seca, confirmando o potencial uso biotecnológico de DHNs de macieira no aumento da tolerância ao déficit hídrico. / Apple tree (Malus x domestica Borkh.) is a temperate fruit crop of great economic importance worldwide and its productivity is related to bud dormancy. Besides genes responsible for the molecular control of the process, a number of proteins and metabolites are also recruited to protect bud integrity, such as dehydrins (DHN) and galactinol synthases (GolS). DHNs are proteins that act on plant adaptive responses to abiotic stresses, while GolS are enzymes that catalyze for the synthesis of galactinol, an essential carbohydrate in the synthesis of raffinose family oligosaccharides (RFOs), which also accumulate in response to abiotic stresses. The objective of this work was to explore bud adaptation to stress conditions that occur during dormancy to identify genes with potential biotechnological applications. DHN and GolS genes were identified and characterized in the apple genome employing in silico tools, experiments under field and controlled conditions, expression analysis, subcellular localization assays, and the generation of transgenic plants. Evolutionary analyses suggest that whole genome duplication (WGD) events were responsible for shaping the evolution and diversification of GolS genes in apple, whereas WGD and tandem duplication events could be held accountable for DHN evolution. Our results suggest that DHNs, galactinol and raffinose integrate a series of mechanisms that act together during dormancy in order to protect bud integrity, besides the carbohydrates being an energy source for budbreak. During evolution, the appearance of new structures and developmental programs, such as buds and dormancy, required the adaptation of already established molecular pathways, partially explaining why bud and seed dormancy share common pathways. Finally, the MdDHN11 gene has been functionally characterized and our results provide evidences that MdDHN11 plays important roles during apple seed development by protecting the embryo and the endosperm from water deficit. Moreover, only the plant overexpressing MdDHN11 survived the water withholding assay, confirming the potential biotechnological use of apple DHNs in increasing tolerance to drought.

Philosophiae Doctor - PhD / The domesticated apple (Malus x domestica Borkh.) has been distributed into diverse climatic conditions worldwide for commercial production of fruit. Apple trees need exposure to cold temperatures, referred to as chill unit (CU) accumulation during winter, in order for budbreak to occur promptly and uniformly after winter. In warmer production areas the application of dormancy breaking chemicals has enabled successful production of high chilling requiring apple cultivars in suboptimal environmental conditions. In the Western Cape region of South Africa it is common orchard practice to apply dormancy breaking chemicals after winter in order to stimulate vegetative growth. If this is not done prolonged dormancy symptoms (PDS) are experienced which include extended rest, less synchronised breaking of buds and reduced branching. An increasing awareness of both global warming and the negative effects associated with the use of chemical sprays (for both pest and disease resistance and growth regulation) has resulted in the need to breed cultivars better adapted to current and future environmental conditions. The breeding of new cultivars using conventional breeding methods is a time consuming process, especially in perennial tree species with a long juvenile phase such as apple. The implementation of marker-assistedbreeding (MAB) and selection (MAS) will enable the selection of favourable genotypes at a very early seedling stage. Although markers linked to genes involved in disease resistance for a variety of known apple pathogens have been identified and are already in use in breeding programs, the genetic determinants of dormancy related characteristics residing within the bud itself (endodormancy) are poorly understood. This hampers the genetic improvement of such characters. Although this study focused on time of initial vegetative budbreak IVB, there are various other characteristics that can be associated with dormancy, such as position and number of budbreak and budbreak duration. The unravelling of the genetic basis of complex traits such as dormancy, can be done through the construction of a genetic linkage map followed by the identification of genomic regions, known as quantitative trait loci (QTL), that can be ssociated with the trait of interest. This study involved the construction of genetic linkage maps for two mapping pedigrees where the low chilling requiring cultivar ‘Anna’ was used as common male parent in crosses with the higher chilling requiring ‘Golden Delicious’ and ‘Sharpe’s Early’. A third mapping pedigree, with ‘Golden Delicious’ as female parent and ‘Prima’ as male parent, was also included. Maps consisted of transferable SSR markers only, facilitating the alignment with the proposed apple reference map (Silfverberg-Dilworth et al., 2006) and adherence to the common LG numbering system now being used for apple genetic linkage maps (Maliepaard et al., 1998). A number of newly developed EST-SSR markers are reported, some of which are candidates for filling large gaps between adjacent SSR markers on the apple reference map. An interactive database was developed to successfully manage the large amount of data generated during this investigation. A selective mapping, or bin mapping strategy (Vision et al., 2000) was developed for two of the three mapping populations in order to facilitate the incorporation and positioning of newly developed markers onto existing genetic linkage maps. This involves the screening of new markers on a small subset of the population, drastically reducing the cost and time involved. Genetic linkage maps constructed allowed for the detection of 18 putative QTLs affecting the time of IVB. Four of these QTLs co-localize with previously identified QTLs. A QTL identified on LG 8 confirms a previously identified QTL (Segura et al., 2007), while one of the QTLs identified on LG 9 might coincide with a QTL identified on the corresponding LG 3 of the genetic linkage map constructed by Conner et al. (1998). Two QTLs identified on LG 10 might coincide with markers found to co-segregate with time of budbreak in an earlier study conducted by Lawson et al. (1995). An additional 14 QTLs involved in time of IVB have been identified. We proposed the testing of four markers in a validation study conducted on a second mapping pedigree derived from a cross between ‘Anna’ and ‘Golden Delicious’. These markers are CH04a12, CH04c06y, CH01h01 and A267. Not only do these markers show significant levels of association with the time of IVB, but segregation of parental alleles from the cultivar ‘Anna’ for two of these markers, CH04c06y and CH01h01, were found to be associated with the time of IVB in different genetic backgrounds. The identification of markers closely associated with time of IVB will facilitate the implementation of MAS in breeding programs in order to breed cultivars that are better adapted to local climatic conditions.

Biennial bearing has been investigated longer and more extensively in apple than in any other fruit tree; however, it remains a serious problem in commercial apple production all over the world. Trees that have become biennial flower profusely and carry a heavy crop in the "on" year, and flower sparsely or not at all and carry little or no crop the following year, the "off" year. Fruit in the "on" year tend to be small, poorly colored, and of low quality, while the few fruit in the "off" year are usually too large, become susceptible to physiological disorders, and also are of poor quality. Without intervention, the crops in both the "on" and "off" years are undesirable and uneconomical. The most common method used by commercial apple growers to try to prevent biennial bearing is chemical fruit thinning, which is an "on" year method of removing a part of the crop before it matures on the tree. In general, growers don't do anything in the "off" year to prevent biennial bearing with the exceptions of fertilizing and pruning lightly. In this study, several experiments were conducted with the cultivars "Braeburn", "Golden Delicious", "Ramey York", and "Fuji" in the "off" year to try and suppress FBI and thus prevent a biennial bearing situation in the following year. The first set of experiments studied the effect of whole-tree and partial-tree defoliation on suppressing spur and lateral flowering and fruit set. Flowering and fruit set were suppressed with defoliation in most cases. Defoliation in early July caused the least amount of flowering the following year and in some cases it was zero. As the defoliation timing and severity was delayed, there was less suppression of flowering and fruit set. Ammonium thiosulfate and Endothal increased flowering but decreased fruit set compared to a control. Gramoxone suppressed flowering and fruit set. In another set of experiments, gibberellic acid (GA) treatments were evaluated to suppress FBI in "off" or light crop years. The GA4+7 treatments suppressed return bloom of both spur and lateral flowers more than the GA3 treatments. The effectiveness of GA declined with delayed application. Both GA treatments reduced lateral flowering the most on the basal 1/3 of the shoot. In a four year study, apple trees were thinned to one fruit per flowering cluster every year from 1997 to 2000. Other trees were thinned to zero fruit or two fruit per flowering cluster in alternate years from 1997 to 2000. Trees thinned to one fruit per flowering cluster had moderate flowering and fruit set the following year. Trees thinned to two fruit per flowering cluster had very little to no flowering the following year. Trees thinned to zero fruit per flowering cluster had a "snowball" bloom the following year. Trees that were alternately thinned to two or zero fruit per flowering cluster were in a biennial bearing situation. / Ph. D.

Leaves and fruit of nine apple (Malus x domestica Borkh.) genotypes were evaluated for insect injury in 1998 and 1999. Foliar and fruit injury from 12 insect species was inconsistently affected by genotype. Spraying trees with oil affected neither fruit insect injury nor fruit phytotoxicity. In choice feeding assays, incidence of Japanese beetle (JB) feeding and leaf area consumed was greater for 'Liberty' than for 'York.' Genotypes did not differ in no-choice feeding assays. Choice and no-choice feeding assays between apple and oak indicated that JB could distinguish host plants in an artificial environment. Trichome density appeared different among three genotypes. 'York', the non-preferred genotype, had highest specific leaf weight and concentration of phloridzin, a feeding repellent. 'Liberty' the preferred genotype, had the lowest specific leaf weight, and had the highest concentration of quercitrin, a feeding stimulant. Olfactory stimuli of JB was evaluated with a Y-tube olfactometer. Beetles preferred the side of the Y-tube containing leaf tissue of apple or Virginia creeper over the side with no leaf. Beetles did not choose one plant species over the other. Bias test of beetle orientation in the Y-tube olfactometer indicated that in the morning, but not the afternoon, beetles preferentially moved into the left side of the Y-tube. Humidity did not affect beetle orientation. In darkness JB preferred a leaf disc over a paper disc and beetles tended to remain on the leaf. / Ph. D.

Bud dormancy is an essential characteristic of deciduous woody perennials, including apple, to cope with the low temperatures during winter. The release from dormancy and subsequent budburst in apple can only occur after fulfillment of chilling and heat requirements. In the Mid-Atlantic region, dormancy release and bud break of apple often coincide with late-spring freezes that cause severe damages to flowers, and small fruitlets. Therefore, the present study aimed to better understand mechanisms underlying bud dormancy in apple, with an ultimate goal of exploring chemical and/or genetic approaches for bloom-time modulation to avoid spring frost. Using two apple cultivars, 'Cripps Pink' and 'Honeycrisp,' representing early- and late-blooming cultivars, respectively, the present study specifically investigated the accumulation kinetics of plant hormones, carbohydrates, and reactive oxygen species (ROS) throughout the dormancy-regrowth cycle. Our results indicated that both cultivars required 1000 chilling hours for endodormancy release, but 'Honeycrisp' required 1000 growing degree hours (GDHs) more than 'Cripps Pink' for ecodormancy release and budburst. Among plant hormones, abscisic acid (ABA) showed remarkably elevated levels in the dormant buds of both cultivars during endodormancy, but its levels were significantly higher in 'Honeycrisp'. The decline of the ABA level at bud burst was combined with increased levels of cytokinin (CK). The ABA accumulation pattern during dormancy paralleled with an upregulation and downregulation of ABA biosynthetic and catabolic genes, respectively. On the other hand, the levels of hydrogen peroxide (H2O2) and superoxide (O2.-) were significantly higher in 'Cripps Pink' than 'Honeycrisp', particularly by the time of endodormancy and ecodormancy release, respectively. Our findings also showed a gradual decline in starch levels with the dormancy progression and increased levels of total soluble sugars (TSS) that were generally higher in the early-blooming cultivars. Transcriptomic profiling and module-trait relationship identified two modules that contrast between two cultivars mainly during eco-dormancy. Gene ontology (GO) analysis indicated that these DEGs were mostly involved in pathways related to hormones and signaling and co-expressed with H2O2 whereas, during ecodormancy pathways related to glutathione metabolism, auxin biosynthesis, carbohydrate metabolism and reproductive development were co-expressed with O2.-. Together, our results suggest that the contrasting bloom dates between 'Cripps Pink' and 'Honeycrisp' can be explained, at least partially, by the differential accumulation levels of ABA, ROS, antioxidants, and their associated genes in the buds of these cultivars throughout the dormancy cycle. / Doctor of Philosophy / Spring frosts represent a significant threat to apple production in many fruit-producing states of the United States including Virginia. The risk of frost damage is rising due to global climate change, and there is a high demand for effective measures to reduce frost damage. Exogenous applications of plant growth regulators (PGRs) to delay bloom has been suggested as an effective frost avoidance strategy, but with limited success. Therefore, the present study aimed to investigate molecular and biochemical pathways regulating bud dormancy and bloom time in apple, which can ultimate lead to novel approaches for bloom delay and frost mitigation. To this end, the accumulation patterns of major plant hormones (e.g. abscisic acid, ABA, cytokinin, CK and jasmonic acid, JA), reactive oxygen species (ROS) and carbohydrates (e.g. starch, sucrose, glucose and fructose) were thoroughly monitored throughout the dormancy-regrowth cycle in two apple cultivars, 'Cripps Pink' and 'Honeycrisp,' representing early- and late-blooming cultivars, respectively. Both these cultivars had similar chilling requirements (1000 chilling hours) but differed in their heat requirements; with 'Honeycrisp' requiring 1000 growing degree hours more than 'Cripps Pink'. Among plant hormones, ABA increased with the progression of dormancy and decreased with dormancy release in both cultivars. However, ABA levels were significantly higher in 'Honeycrisp' compared to 'Cripps Pink'. On the contrary, during dormancy release, the growth-promoting hormone, CK, increased earlier in 'Cripps Pink'. The levels of ROS, e.g., hydrogen peroxide (H2O2), and superoxide (O2.-), were also higher in 'Cripps Pink' than 'Honeycrisp', particularly by the time of endodormancy and ecodormancy release, respectively. Our data showed that starch levels generally declined during dormancy, whereas soluble sugars increased. However, there was no significant alternations in the carbohydrate accumulation profiles between the two cultivars that could account for the differences in their bloom dates. These results were verified further at the transcriptomic level. Using the RNA-sequencing technology, identified two modules that contrast between two cultivars mainly during eco-dormancy. Gene ontology (GO) analysis indicated that these genes were mostly involved in pathways related to hormones and signaling and co-expressed with H2O2 whereas during ecodormancy pathways related to glutathione metabolism, auxin biosynthesis, carbohydrate metabolism and reproductive development were co-expressed with O2.-. Overall, our results suggest that ABA, cytokinin, H2O2, and O2.- may, at least partially, explain the differences in the bloom time between the two apple cultivars. Further analysis of these molecules and their associated genes in other apple cultivars with contrasting bloom dates is necessary for better understanding of bloom time regulation in apple and developing strategies against frost damage.

Apple scab, the most serious disease of apple is caused by fungal pathogen Venturia inaequalis. Knowledge about the apple response to apple scab attack on the cellular and tissue level is insufficient. For studies of Malus-Venturia interaction on the cellular and tissue level, the establishment of methods for cell structures visualization in apple leaves is necessary. In this work, the experimental plant material grown in vitro and ex vitro was successfully established and the method of apple infection by conidia of V. inaequalis was optimized. Various methods of cell components visualization such as vital staining, in situ immunolocalization, transformation, environmental scanning electron microscopy and confocal microscopy, were tested. Cell structures, such as the cytoskeleton, the cell wall and the cuticle were visualized in apple leaves. Preliminary experiments following specific the changes of cell wall structures induced by V. inaequalis attack were performed. Further, changes of cuticle structure, the first barrier for penetration of pathogen to plant tissues during infection, were observed during the leaf ontogenesis. Powered by TCPDF (www.tcpdf.org)

Made available in DSpace on 2017-07-25T19:31:03Z (GMT). No. of bitstreams: 1 Alexandre Pozzobom.pdf: 2410959 bytes, checksum: 345f13c6c1a806e223fa350c8d0ff379 (MD5) Previous issue date: 2016-06-10 / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná / The harvest of fruits of high quality provides increased market value for the fruit grower. A effective fruit thinning is of the most important steps to provide good commercialization. The increased occurrence of hail storms during the growing period resulted in the installation of protective hail nets. This study aimed to evaluate the effects of chemical and mechanical thinning in plums and hand, chemical and mechanical thinning in apples for different hail nets.. For thinning in plums, mechanical thinning was more efficient when compared to chemical thinning. The mechanical thinning treatment reduced fruit set, number of fruit per tree and yield, however it increased fruit size, fruit weight and promoted higher vegetative growth, an important factor to avoid alternating production every year. For apple thinning, mechanical thinning was an effective fruit thinner. It was observed that some treatments like CT-BA required around 300 hours or more per hectare of hand thinning to achieve a satisfactory thinning efficacy. The black hail nets showed a reduction in red colour in apples. The thinning efficacy value (TEV) for hand thinning was 93%, for mechanical thinning was 74%, for chemical thinning with Metamitron was 62% and for chemical thinning with Benzyladenine was 54%. / A colheita de frutos com qualidade proporciona ao produtor agregar valor na venda da fruta. Realizar o raleio dos frutos de maneira eficiente é uma das práticas que proporcionam ao fruticultor melhorar a rentabilidade na produção. Devido as frequentes chuvas de granizo no período de produção de frutas, alguns fruticultores optam por implantar telas antigranizo. Neste contexto, os objetivos deste trabalho foram avaliar os efeitos do raleio químico e mecânico em ameixeira e do raleio manual, químico e mecânico em macieiras sobre diferentes telas antigranizo. Para os raleios em ameixeira, os tratamentos com raleio mecânico foram mais eficientes comparados aos tratamentos com raleio químico. O raleio mecânico reduziu o pegamento de frutos, o número de frutos e a produtividade. Entretanto, proporcionou aumento no tamanho e peso dos frutos e maior crescimento vegetativo, o que pode evitar a alternância de produção. Para o raleio em macieiras, o raleio mecânico foi o mais efetivo. Para o tratamento com benziladenina, foram necessárias mais de 300 horas por hectare de raleio manual para alcançar um raleio eficaz. A utilização de tela preta proporciona redução na coloração vermelha dos frutos de maçã. O Valor da Eficácia do Raleio (VER) para o tratamento com raleio manual foi de 93%, com raleio mecânico de 74%, com raleio químico Metamitron de 62% e o raleio químico Benziladenina 54%.