Academic literature on the topic 'Melon thinning'

ABSTRACT Among many management practices used in melon crops, those that change source: sink relationship, such as pruning and fruit thinning, directly influence production, affect fruit size and its composition, including sugar and vitamin contents. The objective of this study was to evaluate the influence of pruning of the main stem and time of fruit thinning in melon postharvest quality. Thus, two experiments were set up in Mossoró, state of Rio Grande do Norte, each with a melon hybrid (Amaregal and Banzai). Each experiment was conducted in a randomized block, in a (2 x 4) + 1 factorial design, 2 pruning management (with and without pruning), 4 levels of fruit thinning (3, 6, 9 and 12 DARB - days after removal agro textile blanket) and a control (without pruning and thinning), and four replications. Fruits were harvested at commercial maturity and transported to the Laboratory of Food Technology of UFERSA, where they were evaluated for the following characteristics: weight, diameter, length, flesh thickness, flesh firmness, soluble solids, pH, and titratable acidity, soluble solids: titratable acidity ratio and vitamin C. No interaction between factors in any of the experiments was found. Titratable acidity (0.077%) and vitamin C content (3.4 mg/100 g) in Amaregal melon and soluble solids (10.2%) in Banzai melon were lower in the treatments with stem pruning. In Amaregal melon, fruits showed longer length (134 mm) and greater flesh firmness (40 N) when thinning was carried out on 6 DARB, and as thinning was delayed, it found a decrease in the values of soluble solids, SS: TA ratio and pH. In Banzai melon, fruits showed greater flesh thickness (33.5 mm) and SS: TA (247.5) ratio when thinning was carried out on 6 DARB. However, delay in thinning promoted an increase in pH and vitamin C content of the fruits. Pruning of the main stem and thinning season had effect on the quality of Amaregal and Banzai melons in different ways.

Photosynthetic characteristics, concentrations of mineral elements in xylem sap, and some vegetative traits of ‘Khatooni’ melon were compared with those of melons grafted onto three Cucurbita rootstocks cvs., Ace, Shintozwa, and ShintoHongto, and trained with three methods: T1) no pinching and fruit thinning; T2) pinched to produce two lateral branches; and T3) pinched to two branches and all the flowers and lateral branches from lower nodes thinned. Internal CO2 and water use efficiency varied with rootstocks. Stem diameter of scions, aerial fresh and dry weights, mean fruit weight and yield, electric conductivity, pH, and sap volume per plant of grafted plants were higher in grafted melons than in the nongrafted ones. These traits were unaffected by training methods. Mineral concentrations varied considerably depending on the rootstocks and training methods used. Xylem sap collected from the decapitated stem base of grafted melons trained with T2 and T3 methods contained a higher amount of mineral ions, especially NO3−, PO43−, and K+, than did the sap from own-rooted plants. The increase in the mineral levels in sap resulting from grafting was most apparent in ‘Khatooni’ grafted onto ‘ShintoHongto’ rootstock.

Various source–sink perturbations were employed to alter partitioning to orange flesh melon (Cucumis melo L. reticulatus group) and thus to influence fruit biomass and soluble sugar content (indexed as total soluble solids of fruit juice, % TSS), with attention given to the timing of treatment application. A strong relationship existed between harvest index and fruit mass (r2 = 0.88) in control plants, whereas the correlation with fruit TSS was poor (r2 = 0.11). Augmentation of assimilate supply to fruit early in fruit development (before approx. 21 days before harvest, DBH) resulted in more fruit set and increased fruit biomass, whereas augmentation after 21 DBH resulted in increased fruit TSS. Thus, fruit biomass was increased (1644 cf. 1442 g FW per fruit for control, P = 0.02), but not TSS, on plants in which fruit set was delayed (source biomass increased, harvest index decreased from 59% for control to 38%). Treatment of plants with a cytokinin-based vegetative growth inhibitor at 14 DBH produced fruit with higher TSS (11.3 cf. 10.7% for control). Thinning fruit to leave 1 fruit per plant 1 week before harvest increased the proportion of fruit in a population that exceeded a quality control standard of 10% TSS from 20 to 80%. Variations in plant response with timing of treatment application are interpreted in terms of fruit development (cell division, cell expansion, and sugar accumulation phases). Although a detriment to yield (15 cf. 31 t/ha for control), the fruit thinning treatment was recommended for commercial use and a simple model was developed to calculate the required farm-gate price of fruit to make thinning economically viable.

Melon growers in the Lower Rio Grande Valley of Texas have observed in the past that particular sizes of melons and the earliness of melons had a direct effect upon economic returns. A replicated study was carried out during two seasons to determine what specific effects plant density, row arrangement, and cultivar would have on fruit size and yield. The study combined six spacing treatments with three cultivars in a randomized design utilizing five replications on top of raised beds on 80-inch centers. Work was initiated by direct seeding and then thinning to the desired spacing interval in plots located in a commercial field. Plots were harvested by commercial harvesting crews. Results indicate that different plant spacings and honeydew cultivars can result in differences in fruit size, earliness, and returns/acre over different seasons and environments although spacing and cultivar acted independent of one another. Lower plant populations resulted in the production of larger fruit and higher plant populations resulted in the production of smaller fruit. Cultivar did affect the size of fruit produced, with some cultivars resulting in larger melons and others producing more small melons. In both seasons, the double-row 24-inch spacing resulted in an earlier harvest and exhibited a higher percent harvest for the first harvest in both years. Cultivar Sure 7050 was significantly later than either `Honeybrew' or `Morning Ice'. Returns/acre were significantly different between spacing treatments for a majority of harvests. The double-row 24-inch spacing resulted in the highest returns/acre. Both `Morning Ice' and `Sure7050' had significantly higher returns when compared to `Honeybrew'.

Flow-induced bioluminescence provides a unique opportunity for visualizing the flow field around a swimming dolphin. Unfortunately, previous descriptions of dolphin-stimulated bioluminescence have been largely anecdotal and often conflicting. Most references in the scientific literature report an absence of bioluminescence on the dolphin body, which has been invariably assumed to be indicative of laminar flow. However, hydrodynamicists have yet to find compelling evidence that the flow remains laminar over most of the body. The present study integrates laboratory, computational and field approaches to begin to assess the utility of using bioluminescence as a method for flow visualization by relating fundamental characteristics of the flow to the stimulation of naturally occurring luminescent plankton. Laboratory experiments using fully developed pipe flow revealed that the bioluminescent organisms identified in the field studies can be stimulated in both laminar and turbulent flow when shear stress values exceed approximately 0.1 N m-2. Computational studies of an idealized hydrodynamic representation of a dolphin (modeled as a 6:1 ellipsoid), gliding at a speed of 2 m s-1, predicted suprathreshold surface shear stress values everywhere on the model, regardless of whether the boundary layer flow was laminar or turbulent. Laboratory flow visualization of a sphere demonstrated that the intensity of bioluminescence decreased with increasing flow speed due to the thinning of the boundary layer, while flow separation caused a dramatic increase in intensity due to the significantly greater volume of stimulating flow in the wake. Intensified video recordings of dolphins gliding at speeds of approximately 2 m s-1 confirmed that brilliant displays of bioluminescence occurred on the body of the dolphin. The distribution and intensity of bioluminescence suggest that the flow remained attached over most of the body. A conspicuous lack of bioluminescence was often observed on the dolphin rostrum and melon and on the leading edge of the dorsal and pectoral fins, where the boundary layer is thought to be thinnest. To differentiate between effects related to the thickness of the stimulatory boundary layer and those due to the latency of the bioluminescence response and the upstream depletion of bioluminescence, laboratory and dolphin studies of forced separation and laminar-to-turbulent transition were conducted. The observed pattern of stimulated bioluminescence is consistent with the hypothesis that bioluminescent intensity is directly related to the thickness of the boundary layer.

Objective: This study aimed to assess the productivity and quality of a melon crop treated with fruit thinning and main stem pruning under field conditions. Experimental Design: The treatments comprised the amount of fruit thinning in the plant (one, two and without thinning) and the period of main stem pruning (35, 40, 45 and 50 days after transplanting - DAT). The crop was set up in a randomized block design factorial of type 3x4, with five replications. Location and Duration of the Study: The experiment carried out at the Center for Agrifood Science and Technology (CCTA) of the Federal University of Campina Grande (UFCG), Campus Pombal - PB, Brazil, from December 2016 to February 2017. Methodology: The Hopey King hybrid of the Cantaloupe group was cultivated at a spacing of 2.0 x 0.4 m. Results: The plants without thinning of fruits provided lower values ​​of leaf area and fruits of lower mass. However, due to their higher quantity per hectare, the crop total productivity was high. On the other hand, plants with fewer fruits had the highest values ​​of soluble solids, total and non-reducing soluble sugars. The leaf area, fruit mass, total productivity, and the concentration of reducing and non-reducing soluble sugars were higher when the plants were pruned at 35 DAT. Conclusion: The fruit thinning and main stem pruning affected the production and quality of melon fruits significantly. For more demanding markets, we recommend to treat the plants with one or two fruits and prune at 35 days after transplantation, aiming to enhance the quality variables.

Total soluble solids (TSS) is a reliable indicator of melon eating quality, with a minimum standard of 10% recommended. The state of Australian melon production with respect to this quality criterion was considered within seasons, between growing districts and over seasons. It was concluded that improvement in agronomic practice and varietal selection is required to produce sweeter melons. The scientific literature addressing melon physiology and agronomy was summarised, as a background to the work that is required to improve melon production practices in Australia. The effect of source sink manipulation was assessed for commercially grown and glasshouse grown melon plants. The timing of fruit thinning, pollination scheduling, the application of a growth inhibitor and source biomass removal were assessed in relation to fruit growth and sugar accumulation. Results are interpreted against a model in which fruit rapidly increase in weight until about two weeks before harvest, with sugar accumulation continuing as fruit growth ceases. Thus treatment response is very dependant on timing of application. For example, fruit thinning at 25 days before harvest resulted in further fruit set and increased fruit weight but did not impact on fruit TSS (at 9.8%, control 9.3%), while thinning at 5 days before harvest resulted in a significant (Pless than 0.05) increase in fruit TSS (to 10.8%, control 9.3%) and no increase in fruit weight or number. A cost/ benefit analysis is presented, allowing an estimation of the increase in sale price required to sustain the implementation of fruit thinning. The effect of irrigation scheduling was also considered with respect to increasing melon yield and quality. To date, recommended practice has been to cause an irrigation deficit close to fruit harvest, with the intent of 'drying out' or 'stressing' the plant, to 'bring on' maturity and increase sugar accumulation. Irrigation trials showed that keeping plants stress-free close to harvest and during harvest, facilitated the production of sweeter fruit. The maintenance of a TSS grade standard using either batch based (destructive) sampling or (non-invasive) grading of individual fruit is discussed. On-line grading of individual fruit is possible using near infrared spectroscopy (NIR), but the applicability of the technique to melons has received little published attention. Tissue sampling strategy was optimised, in relation to the optical geometry used (in commercial operation in Australia), both in terms of the diameter and depth of sampled tissue. NIR calibration model performance was superior when based on the TSS of outer, rather than inner mesocarp tissue. However the linear relationship between outer and middle tissue TSS was strong (r2 = 0.8) in immature fruit, though less related in maturing fruit (r2 = 0.5). The effect of fruit storage (maturation/senescence) on calibration model performance was assessed. There was a negligible effect of fruit cold storage on calibration performance. Currently, the agronomist lacks a cost-effective tool to rapidly assess fruit TSS in the field. Design parameters for such a tool were established, and several optical front ends compared for rapid, though invasive, analysis. Further, for visualisation of the spatial distribution of tissue TSS within a melon fruit, a two-dimensional, or hyper-spectral NIR imaging system based on a low cost 8-bit charge coupled device (CCD) camera and filter arrangement, was designed and characterised.

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Pruning and thinning are practices that can change the source:sink relations and thus influence the quality and fruit storage capacity. This study evaluated the influence of the pruning of the main stem and the fruit thinning in quality and postharvest conservation of melon. For this, two experiments were conducted, with Galia melon (hybrid Amaregal) and Charentais melon (hybrid Banzai), both with two phases, field and laboratory. In the field, the plants were submitted to the pruning of the main stem and the fruit thinning; the fruits were harvested at 66 and 74 days after sowing (DAS), respectively for Galia and Charentais melon. In the laboratory, the fruits were cleaned, characterized and stored in the freezer. The experiment was conducted in split-plot, and the portion composed of the factorial 2 x 4 + 1: pruning (pruning and unpruning), thinning times (32, 35, 38 and 41 DAS to Galia melon; and 42, 45, 48 and 51 DAS for the Charentais melon) and an additional control (unpruning and unthinning); and the sub-plot was constituted by the storage times (0, 7, 14, 21 and 28 days), with four blocks. The following analyzes were performed: number of fruits per plant (NFP), fruit weight (FW), productivity (PROD), weight loss (WL), external (EA) and internal appearance (IA), epicarp and mesocarp color, flesh firmness (FF), titratable acidity (TA), soluble solids (SS) , total soluble sugars (TSS), reducing sugars (RS) and non-reducing sugar (NRS), and vitamin C (VITC). In the Galia melon, pruning improved the epicarp color and increased the NRS, but reduced the SS. Thinning to 41 DAS depreciated the EA and reduced SS, TSS and NRS, but was positive for epicarp and mesocarp color, and increased VITC. Pruning reduced the TA and the loss in FF at 14 and 28 days of storage, respectively. Pruning associated with thinning to 38 DAS reduced the WL after 28 days of storage and result in an increased RS. In storage was observed decreasing in EA, IA, SS, RS, NRS, TSS and VITC. In the Charentais melon, the pruning reduced WL to 28 days of storage. Pruning also decreased TA. The treatments with pruning and thinning positively influenced the fruit epicarp color. Thinning to 42 DAS increased the SS and SS/TA ratio. In storage period there was a reduction in EA, IA, FF, TA, RS, VITC and increase in SS, SS/TA ratio, TSS and NRS
Poda e raleio são práticas que podem alterar as relações fonte:dreno do meloeiro e, assim influenciar a qualidade e capacidade de armazenamento dos frutos. Assim, este estudo objetivou avaliar a influência da poda da haste principal e do raleio dos frutos na qualidade e conservação pós-colheita de melão. Para isto, foram realizados dois experimentos, sendo um com o melão Gália ‘Amaregal’ e o outro com melão Charentais ‘Banzai’, ambos com uma fase de campo e outra de laboratório. Em campo, as plantas foram submetidas à poda da haste principal e ao raleio dos frutos, com a colheita ocorrendo aos 66 e 74 dias após a semeadura (DAS), respectivamente para o melão Gália e Charentais. Os frutos foram levados para o laboratório, onde foram higienizados, caracterizados e armazenados em câmara fria. Os experimentos foram conduzidos em esquema de parcelas sub-divididas, sendo a parcela constituída pelo fatorial 2 x 4 +1: poda (sem poda e com poda), épocas de raleio (32, 35, 38 e 41 DAS para o melão Gália; e 42, 45, 48 e 51 DAS para o melão Charentais) e uma testemunha adicional (sem poda e sem raleio); e a sub-parcela constituída pelo armazenamento (0, 7, 14, 21 e 28 dias), com quatro blocos. As seguintes análises foram realizadas: número de frutos por planta (NFP), massa média dos frutos (MMF), produtividade (PROD), perda de massa (PM), aparência externa (AE) e interna (AI), cor do epicarpo e mesocarpo, firmeza de polpa (FP), acidez titulável (AT), teor de sólidos solúveis (SS), açúcares solúveis totais (AST), açúcares redutores (AR) e não-redutores (ANR), e vitamina C (VITC). Verificou-se no melão Gália que a poda da haste principal do meloeiro realçou a cor do epicarpo e aumentou o ANR, porém reduziu os SS. O raleio aos 41 DAS depreciou a AE e reduziu os SS, AST e ANR, mas foi positivo para a cor do epicarpo e mesocarpo, bem como aumentou a VITC. A poda reduziu a AT e a perda na FP dos frutos aos 14 e 28 dias de armazenamento, respectivamente. A poda associada ao raleio aos 38 DAS reduziu a PM aos 28 dias de armazenamento e propiciou incremento no AR dos frutos. E ao longo do armazenamento houve redução nas notas de AE e AI e nos teores de SS, AR, ANR, AST e VITC. Por outro lado, no melão Charentais, a poda reduziu a PM dos frutos aos 28 dias de armazenamento. A poda também diminuiu a AT dos frutos. Os tratamentos de poda e raleio influenciaram positivamente a cor do epicarpo dos frutos. O raleio aos 42 DAS elevou os SS e a relação SS/AT. Durante o período de armazenamento houve redução na AE, AI, FP, AT, AR e VITC, e incremento nos SS, relação SS/AT, AST e ANR
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