Regulation of fruit set ensures optimal crop load to attain maximal ratio of fruit sizes with high price. Chemical fruit thinning is currently the most available and safe method for orchards with ...high flower set. Objective of our trial was to test wide range of known but also new prospective chemical thinners in young pear orchard and determine its economic potential. In our experiment, thinning effect assessed by number of fruits per 100 flower clusters was insignificant among treatments. The exception was the application of abscisic acid in concentration of 300 ppm which caused excessive thinning and partial defoliation. Though some treatments showed only insignificant mild thinning effects, their impact on ratio of fruit sizes was obvious and important from the practical point of view. Real economical example counting possible incomes from hectare shows, that even small thinning effect can have significant positive impact on production profitability.
•Prohexadione calcium efficiently controls vegetative growth of ‘Le Conte’ pear trees.•Yield components were not affected by P-Ca.•Return bloom and return yield were not reduced by P-Ca.•No negative ...effects of P-Ca on fruit quality attributes were observed.
Different studies describing Prohexadione calcium (P-Ca) as an efficient tool to reduce shoot growth have been extensively reported, but these studies are usually performed in typical temperate climate regions. However, a complete analysis of the effects of P-Ca in pear trees in regions of warm-winter climates has not been performed. Therefore, the objective of this study was to evaluate the effect of different rates of P-Ca on vegetative growth, production and fruit quality of ‘Le Conte’ pear trees, in warm-winter climate conditions. The experiment was conducted during the 2013/2014 and 2014/2015 seasons, in a six year old ‘Le Conte’ pear orchard, trained to a central-leader system, with spacing of 1.5×4.8m, grafted onto Pyrus calleryana. Different P-Ca rates were applied (100, 200, 300, 400mgL−1) in different biological stages: first in early spring (shoots ∼2.5 and 5cm long) for all treatments and the others when shoot growth resumed (GR), but only for some treatments. Variables for vegetative growth, yield components and fruit quality at harvest and post-harvest were evaluated. Shoot length was measured on 10 one-year-old shoots evenly selected and tagged at the time of the first application and, then, at biweekly intervals until the end of the season. The use of P-Ca was effective to control vegetative growth in both seasons, at different rates. At ∼90days after full bloom (DAFB), P-Ca treated shoots had a pronounced second flush of growth, requiring an additional application of P-Ca in both seasons. In the 2013/2014 season, the only time of P-Ca reapplication was at 93 DAFB for the rates of 100 and 200mgL−1, which was enough to check shoot growth throughout the season, but in the 2014/2015 season, three shoot growth flushes were observed according to P-Ca rate, requiring additional P-Ca applications. Unlike the first season, P-Ca reapplication was efficient to reduce shoot length relative to trees treated once with P-Ca. In both seasons, fruit set, number of fruits per tree, yield, average fruit weight, fruit diameter, estimated yield, return bloom, and return yield were not affected by P-Ca applications. P-Ca applications did not alter the qualitative attributes of the fruits of ‘Le Conte’ pear trees at harvest and when they were stored for a period of 30days of regular air cold storage (RACS)+3days of ripening period (RP) in both seasons. These results implicate P-Ca as a potential tool to manage vigor of ‘Le Conte’ pear trees in warm-winter conditions, given its efficiency to control vegetative growth without negatively affecting yield components.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Given that Brazilian pear production is unable to meet the annual demand, to consider the possible expansion to non traditional growing regions, turns interesting. Even though under tropical ...semi-arid conditions pear trees have vigorous vegetative growth, a negative influence on flower bud differentiation and formation affects fruit yield. Our study aimed to evaluate the inhibition efficiency of paclobutrazol (PBZ) on gibberellin biosynthesis, vegetative growth, and carbohydrate production in two pear-treecultivars (‘Santa Maria’ and ‘Hosui’) grown under semi-arid conditions. To this end, two experiments were conducted, one for each pear-tree cultivar. The experimental designs consisted of randomized blocks, with factorial arrangement (5x2x4), corresponding to PBZ doses (0.0, 0.5, 1.0, 1.5, and 2.0 g per linear meter of plant canopy), PBZ application forms (soil and foliar), and evaluation dates (30, 60, 90, and 120 days after application). Both soil and foliar applications inhibited gibberellin biosynthesis in both cultivars, especially after 120 days of application. PBZ affected leaf total soluble carbohydrates and reduced sprout growth in both cultivars. Although PBZ can be potentially used in pear management, further studies are still required to determine specific management practices in tropical semi-arid zones.
Highlights:
Inhibition of gibberellin biosynthesis is more efficient with soil application of paclobutrazol.
Soil application of paclobutrazol results in greater production of carbohydrates.
There is a difference in sensitivity to the effects of paclobutrazol among pear varieties.
The non-application of paclobutrazol results in late maturation of the branches, compromising floral induction.
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•Reproductive spurs are the main structure related to the greater yield of pears in the tropics.•The management of Pruning and pears in the tropics should be light due to the evolution of vegetative ...brindles.•'Seleta' and 'Shinseiki' showed better adaptability and reproductive stability in this study.
Pear production in the tropics is limited not only by the reduced number of cultivars more adapted to places with higher temperatures, but also due to the lack of strategies for correct culture management. The intensity and the way of pruning the branches and the vegetative and reproductive structures are external factors that most influence the production and quality of pears. Thus, the aim was to evaluate the structure type that is related with the yield levels of pear trees and to establish strategies for the pruning of cultivars with greater adaptability and reproductive stability in the tropics. The experimental design was complete randomized blocks in the factorial design of split-plot in time, being six pear tree cultivars and two crop years. The duration of the phenophases in days, the percentage of vegetative spurs, reproductive spurs, reproductive brindles, vegetative brindles, bourses, yield per plant, and the number of fruits per plant were evaluated. Moreover, the adaptability and reproductive stability of species were verified. The pruning should be guided in order to maintain the reproductive spurs, the pear tree’s main developed reproductive structure in the tropics and related to the greater yield of pears. Pruning in the tropics should be mild due to the evolution of vegetative brindles. There is no difference in the total length of the cultivar’s phenological cycle regarding the reproductive spurs and reproductive brindles. 'Seleta' and 'Shinseiki' cultivars show greatest adaptability and reproductive stability to be cultivated in the tropics.
A produção de peras nos trópicos é limitada não somente pelo número reduzido de cultivares mais adaptadas a locais com temperaturas mais elevadas, mas também, devido à falta de estratégias para o manejo cultural correto. A intensidade e a forma de como se podar os ramos e as estruturas vegetativas e reprodutivas são um dos fatores externos à planta que mais influenciam a produção e qualidade das peras. Sendo assim, o objetivo foi avaliar o tipo de estrutura que possui correlação com os níveis de produtividade das pereiras e estabelecer estratégias para a poda de cultivares que apresentam maior adaptabilidade e estabilidade reprodutiva nos trópicos. O delineamento experimental utilizado foi o de blocos inteiramente casualizados, no esquema fatorial de parcelas subdivididas no tempo, sendo seis cultivares de pereira e duas safras agrícolas. Foram avaliadas a duração das fenofases em dias, a porcentagem de dardos, lamburdas, brindilas floríferas, brindilas vegetativas, bolsas, a produção por planta e o número de frutos por planta. Além disso, foi verificada a adaptabilidade e estabilidade reprodutiva das espécies. A poda deve ser orientada para se manter as lamburdas, principal estrutura reprodutiva desenvolvida nas pereiras nos trópicos e que está relacionada à maior produção de peras. A poda nos trópicos deve ser branda devido à evolução das brindilas vegetativas. Não há diferença na duração total do ciclo fenológico das cultivares para as lamburdas e brindilas floríferas. ‘Seleta’ e ‘Shinseiki’ são as cultivares que apresentam maior adaptabilidade e estabilidade reprodutiva para serem cultivadas nos trópicos.
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The aim of this study was to evaluate the influence of boron foliar application, branch girdling and plant growth regulators on the performance of pear trees cv. Garber. The experiment was arranged ...in a randomized block design with three replications. Treatments consisted of different boron rates (220, 440, 660 and 880 mL 100 L-1), branch girdling, and the plant growth regulators Promalin® (benzyladenine + gibberellins AG4+7) (560 mL 100 L-1) and Biozyme * TF (200 mL 100 L-1). The percentage of fruit set, stem length, fruit length, fruit diameter, flesh firmness, soluble solids and yield were assessed. The greatest fruit set was observed with Promalin® in both years and also boron and Biozyme * TF in the second year. The use of Promalin® increased peduncle length, fruit height but negatively affected soluble solids. Yield was also increased by this plant growth regulator and boron. Concluding, Promalin® improves fruit set, yield, and fruit quality and boron positively influence yield.
The low fruit set is one of the main factors leading to poor yield of pear orchards in Brazil. The exogenous application of thidiazuron (TDZ) and aminoethoxyvinilglycine (AVG) has shown promising ...results in some pear cultivars and other temperate fruit trees. The objective of this study was to evaluate the effect of TDZ and AVG on fruit set, yield, and fruit quality of 'Hosui' and 'Packham's Triumph' pears. The study was performed in a commercial orchard located in São Joaquim, SC. Plant material consisted of 'Hosui' and 'Packham's Triumph' pear trees grafted on Pyrus calleryana. Treatments consisted on different rates of TDZ (0 mg L-1, 20 mg L-1, 40 mg L-1 and 60 mg L-1) sprayed at full bloom for both cultivars. An additional treatment of AVG 60 mg L-1 was sprayed one week after full bloom in 'Hosui'. The fruit set, number of fruit per tree, yield, fruit weight, seed number, and fruit quality attributes were assessed. Fruit set and yield of both cultivars are consistently increased by TDZ, within the rates of 20 to 60 mg L-1. Besides, its application increased fruit size of 'Hosui' and did not negatively affect fruit quality attributes of both cultivars.
ABSTRACT Prohexadione calcium (P-Ca) has been reported to effectively control shoot growth in several pear cultivars, but with a few reports about its efficiency under the climatic conditions of ...southern Brazil. Therefore, the objective of this study was to evaluate vegetative growth, production, and fruit quality of ‘Smith’ pear trees in response to the use of different rates of P-Ca in the climatic conditions of southern Brazil. The experiment was conducted during the 2013/2014 and 2014/2015 seasons, in a 6-year-old ‘Smith’ pear orchard, trained to a central-leader system, with spacing of 1.5 × 4.8 m, grafted onto Pyrus calleryana Decne. Different P-Ca rates were applied (100, 200, 300, and 400 mg∙L–1) in different stages: first, in early spring for all treatments, and the others when shoot growth resumed (GR), but only for some treatments. Variables for vegetative growth, yield components and fruit quality at harvest and post-harvest were evaluated. The use of P-Ca was effective to control vegetative growth in both seasons, at different rates. Yield components were not affected by P-Ca applications in 2013/2014, except return bloom and return yield. In 2014/2015 season, P-Ca applications positively affected yield components, except average fruit weight and return bloom. P-Ca applications did not alter the qualitative attributes of the fruits of ‘Smith’ pear trees at harvest and after a period of cold storage. These results implicate P-Ca as a potential tool to manage vigor of ‘Smith’ pear trees in climatic conditions of southern Brazil.
The current study was focused on molecular analysis using internal cpDNA trnL intron sequence, antioxidant activity, total phenolics and flavonoid contents of fifteen pyrus genotypes. Quite ...variations were determined in biochemical characteristics and molecular systematic analysis of genotypes evaluated. "Y. Karçin" genotype was detected as the best graded genotype based on the high contents of the total phenolic (7,92 mg GAE/g) and total flavonoid (4,50 mg RE/g) content. The obtained results showed that, genotypes could be categorized of six main clades with robust bootstrap values, which might be useful to improve genetic diversity among genotypes for breeding.
Different studies describing Prohexadione calcium (P-Ca) as an efficient tool to reduce shoot growth have been extensively reported, but these studies are usually performed in typical temperate ...climate regions. However, a complete analysis of the effects of P-Ca in pear trees in regions of warm-winter climates has not been performed. Therefore, the objective of this study was to evaluate the effect of different rates of P-Ca on vegetative growth, production and fruit quality of âLe Conteâ pear trees, in warm-winter climate conditions. The experiment was conducted during the 2013/2014 and 2014/2015 seasons, in a six year old âLe Conteâ pear orchard, trained to a central-leader system, with spacing of 1.5Ã4.8m, grafted onto Pyrus calleryana. Different P-Ca rates were applied (100, 200, 300, 400mgLâ1) in different biological stages: first in early spring (shoots â¼2.5 and 5cm long) for all treatments and the others when shoot growth resumed (GR), but only for some treatments. Variables for vegetative growth, yield components and fruit quality at harvest and post-harvest were evaluated. Shoot length was measured on 10 one-year-old shoots evenly selected and tagged at the time of the first application and, then, at biweekly intervals until the end of the season. The use of P-Ca was effective to control vegetative growth in both seasons, at different rates. At â¼90days after full bloom (DAFB), P-Ca treated shoots had a pronounced second flush of growth, requiring an additional application of P-Ca in both seasons. In the 2013/2014 season, the only time of P-Ca reapplication was at 93 DAFB for the rates of 100 and 200mgLâ1, which was enough to check shoot growth throughout the season, but in the 2014/2015 season, three shoot growth flushes were observed according to P-Ca rate, requiring additional P-Ca applications. Unlike the first season, P-Ca reapplication was efficient to reduce shoot length relative to trees treated once with P-Ca. In both seasons, fruit set, number of fruits per tree, yield, average fruit weight, fruit diameter, estimated yield, return bloom, and return yield were not affected by P-Ca applications. P-Ca applications did not alter the qualitative attributes of the fruits of âLe Conteâ pear trees at harvest and when they were stored for a period of 30days of regular air cold storage (RACS)+3days of ripening period (RP) in both seasons. These results implicate P-Ca as a potential tool to manage vigor of âLe Conteâ pear trees in warm-winter conditions, given its efficiency to control vegetative growth without negatively affecting yield components.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The entomosporiosis is considered a major disease of pear in Brazil, one of the most responsible for premature defoliation in plants. The objective of this study was to characterize the ...susceptibility of pear tree cultivars Housui, Cascatense, Packam's Triumph and Rocha for the intensity of leaf spot entomosporiosis. The experiment was conducted at the experimental orchard of the State University of the Midwest (Unicentro), Paraná State, Guarapuava County, Brazil during the 2013/2014 season. The incidence and severity were monitored during 77 days from the beginning of the symptoms in 25 leaves of 8 plants per cultivar. With these data the following variables were calculated: early onset of symptoms (EOS), maximum incidence and severity (Imax and Smax) and the Area Under the Incidence Progress Curve (AUIPC) and Severity (AUSPC). In addition, the data were checked for severity and the best adjustments for the monomolecular, logistic and exponential models were tested. From these results it is clear that all the studied cultivars are susceptible to leaf spot entomosporiosis, however, Housui pear cultivar presented higher endurance while Rocha and Cascatense cultivars presented greater susceptibility to this disease.
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