Acceptable Fruit Quality Research Articles

Citral-thymol based synergistic shellac coatings enhanced shelf life of Kinnow fruit stored under low temperature conditions

Microbial spoilage incurs the main cause of reduced shelf life of Kinnow during storage and transportation. This study aimed to evaluate the postharvest application of plant-derived citral and thymol-based shellac wax coatings on ‘Kinnow’ mandarin under controlled conditions (5–7 °C, 90–95 % relative humidity (RH)) over a 75-day storage period. The fruit were coated with shellac wax (SH) supplemented with citral (1.0 %, CSH), thymol (1.0 %, TSH) and citral-thymol combined formulation (1.0 %, CTSH (1:1)). Rheology studies revealed that the Herschel–Bulkley model was the best fit for all coating solutions, ensuring desirable spreadability and adhesion. The CTSH-coating outperformed all other treatments by reducing mean spoilage to 0.46% as compared to commercial shellac (6.71%) over a period of 75 days under cold store conditions. The treated fruit could control the physiological weight loss to 5.73 % as compared to commercial SH coatings (7.62 %) for 60 days. The study concluded that CTSH-coated Kinnow fruit can be stored up to 60 days under cold store conditions at 5–7 °C and 90–95 % RH with acceptable fruit quality (sensory score 7.83). The activities of cell wall degrading enzymes such as Pectin methylesterase (PME) and cellulase were also found to be retarded, contributing to prolonged shelf life. Therefore, these coatings may offer a green substitute to the synthetic analogues, with no health side effects for extending the postharvest shelf life of Kinnow up to 60 days under cold store conditions.

Flowering Phenology and Evaluation of Pollination Techniques to Achieve Acceptable Fruit Quality of Red-fleshed Pitaya (Hylocereus polyrhizus) in Sabah, East Malaysia

As red-fleshed pitaya (Hylocereus polyrhizus) is not native to the tropical environment of the Malaysian state of Sabah, Borneo, little is known about its flowering phenology, pollination requirements, and potential pollinators, which has discouraged many farmers from growing this crop. Therefore, this study aimed to examine better pollination techniques to achieve acceptable fruit quality for red-fleshed pitaya production under local climatic conditions. For this purpose, stingless bees (Tetragonula laeviceps), self-pollination, natural pollination, and hand pollination were used. Pitayas were planted in the field from January 2018 to February 2022, and 40 flowers were observed to obtain data on flowering phenology and fruit quality. This study observed that anthesis of red-fleshed pitaya took about 24 hours in all treatments, depending on the local climate, starting at 6.30 p.m. and ending at 6.30 p.m. the next day. Besides self-pollination, the pitaya flowers were also successfully pollinated by natural, hand, and stingless bees. However, the fruits pollinated by stingless bees were the heaviest, longest, and thickest, indicating that the integration of pitaya cultivation and stingless bees is likely to improve the yield and quality of the fruits on the farm.

Utilizing genetic diversity to select tomato lines tolerant of tomato yellow leaf curl virus based on genotypic coefficient of variation, heritability, genotypic correlation, and multivariate analyses

Tomato yellow leaf curl virus (TYLCV) is one of the most destructive pathogens for tomato crops. The development of TYLCV-tolerant tomato lines (TLs) requires a thorough understanding of their genetic variability and relationships among lines and in traits of interest. Twelve F9 TLs were evaluated for phenotypic TYLCV tolerance, vegetative growth, yield, and fruit quality during the 2018 and 2019 fall seasons to identify elite breeding lines. TLs were selected by a bulk selection method from segregating generations of the commercial F1 hybrids TH99802 (TLs 1–6) and TH99806 (TLs 7–12). TLs exhibited either mild or no symptoms. The TYLCV titer varied between 0.8 × 105 and 3.9 × 105 in symptomless TLs plants compared to 56.7 × 105 in severely symptomatic plants of susceptible ‘Castlerock.’ Across both seasons, TL-3, TL-5, and TL-8 exhibited the highest total and marketable plant yields, TYLCV tolerance, and acceptable fruit quality. Most traits had high estimates of genetic variance, genotypic coefficient of variance, and broad sense heritability. Our results indicated that there was sufficient genetic variability for selection of the best lines. Principal component analysis and hierarchical cluster analysis indicated that the TLs were highly diverse of the evaluated traits and could be divided into three clusters. Cluster 1, which included TL-1, TL-3, and TL-8, performed better for TYLCV tolerance and economically important traits. Clusters 1 and 2 showed the greatest degree of dissimilarity. Therefore, crossing parents from Cluster 1 with 2 is predicated to maximum recombination for improve genotypes.

Potential Adoption of the F2 Generation of Some TYLCV-Resistant Tomato Hybrids in Commercial Production under Natural Field Infection

The economic feasibility of using the tomato yellow leaf curl virus (TYLCV) resistant F1 tomato hybrids (Solanum lycopersicum L.) may be improved with the possibility of using their F2 generation in commercial production. Hence, this study was performed to evaluate the F1 and F2 generations of 15 TYLCV resistant/tolerant commercial tomato hybrids during the 2018 and 2019 fall season to identify the best hybrids and F2 populations for commercial production. Both F1 and F2 populations were evaluated separately for TYLCV resistance, yield, and fruit quality traits. Broad sense heritability (H2b) values of TYLCV-resistance were high, being > 60% in hybrids 186, Goldstone, Rabha, SV0922 and SV8320 in both seasons. F1 and F2 populations of ‘186’, ‘Dania’, ‘PS550’, ‘Rozalina’, ‘SV0922’, ‘SV8320’, and ‘Tyrmes’ had the highest total yield (TY)/plant, low TYLCV disease (TYLCVD) mean scores, acceptable fruit quality traits, and average fruit weight > 80 g. Desirable inbreeding depression (ID) values were observed for TYLCVD-mean score in F2 populations of most evaluated hybrids; for TY/plant in F2 populations of ‘SV3773’ in both seasons, and in populations of ‘186’, ‘448’, ‘Goldstone’, ‘Rabha’, ‘SV8320’ and ‘SV0922’ in the second season. Most hybrids had desirable significant ID values for fruit quality traits. Accordingly, it is concluded that the F2 populations of hybrids 186, SV0922 and SV8320 may be used in commercial tomato production under TYLCV-infection in fall season, as these populations recorded high h2b values for TYLCV-resistance trait and desirable ID for TYLCV-resistance, yield, and fruit quality traits.

Effects of salicylic acid, putrescine and moring leaf extract application on storability, quality attributes and bioactive compounds of plum cv. 'Golden Japan'

Background: Plum fruits constitute a good source of natural antioxidant substances. Particularly, plums contain large amounts of phenolic compounds and flavonoids that have natural antioxidant activity which is useful to human health. The study aimed to evaluate the effects of foliar sprays with salicylic acid (SA), putrescine (PUT) and moringa leaf extract (MLE) on the fruit quality attributes and bioactive compounds of 'Golden Japan' plums under cold storage conditions. Plum trees were sprayed twice; at fruit set stage and one month later during seasons 2018 and 2019 by combinations from SA (3 and 4 mmol/L), PUT (3 and 4 mmol/L) and MLE (5 and 10%), as well as distilled water (control). Fruits were harvested at maturity stage and stored at 0°C with relative humidity 85-90% for eight weeks. Results: With advance storage period, fruit weight loss, total soluble solids (TSS), total carotenoids content (TCC) and total phenolics content (TPC) increased significantly while the fruit firmness, lightness (L*), hue angle (h°) of colour, titratable acidity (TA), total flavonoids content (TFC) and antioxidant activity (AA) decreased significantly (P < 0.05). Statistically significant differences were observed between different treatments in maintenance on all measured parameters when compared to control. At the same time, a combined SA at 3mmol/ L, PUT at 4 3mmol/ L and MLE at 10% treatment was found to be more effective than other treatments in decreasing the weight loss, softening and maintaining titratable acidity, total carotenoids, total phenolics, total flavonoids and antioxidant activity in plum fruits during storage at 0 °C.Conclusion: It was concluded that preharvest treatment of plum fruits with salicylic acid, putrescine and moringa leaf extract was effective in delaying the ripening processes and can be used commercially to extend the storage life of postharvest plum fruits with acceptable fruit quality.

Effects of the bioregulators ACC, 6-BA, ABA, and NAA as thinning agents on Gala apples

Gala apple (Malus domestica Borkh.) trees are prone to heavy cropping but respond to chemical fruitlet thinners to reduce crop load and improve fruit quality. Environmental concerns over the fate of the chemical fruitlet thinner carbaryl is widely acknowledged, but crop load management options are limited. In southern Ontario, Gala trees were treated with new thinning compounds or combinations to determine post-bloom thinning efficacy and resulting fruit quality. Treatments included 6-benzyladenine (6-BA) combined with naphthaleneacetic acid (NAA) or abscisic acid (ABA), and 1-aminocyclopropane-1-carboxylic acid (ACC) alone applied at 9 mm in 2014 and 17 mm in 2015. The treatment NAA + 6-BA produced unacceptably small “pygmy” fruit when applied at 17 mm fruitlet diameter. ABA at 150 and 300 mg L−1and ACC at 150 mg L−1, when applied at 17 mm fruitlet diameter, resulted in acceptable fruit set, crop load, and quality results in comparison with the carbaryl thinner in 1 yr. The bioregulators ACC and ABA combined with 6-BA showed commercial potential for thinning Gala fruit but require further evaluation.

Physicochemical changes in ‘Santa Rosa’ plum fruit treated with melatonin during cold storage

This study was conducted to investigate the effects of melatonin treatments on biochemical compounds and postharvest quality plum cv. “Santa Rosa” during storage at 1 °C for 40 days. The plums were dipped in 0, 1, 10, 100 and 1000 µmol l−1 melatonin solution immediately after harvest. The changes of plums were assessed at 10-day intervals by evaluating the following quality parameters: weight loss, firmness, soluble solids content (SSC), titratable acidity (TA), SSC:TA, ascorbic acid content, total anthocyanin content, total phenolic content, antioxidant activity and decay rate. The results showed that treatment of melatonin at 100 and 1000 µmol l−1 was effective in reducing weight loss and maintaining greater firmness. However, low doses of melatonin treatment had no effect positively on carbohydrate, acids, biochemical compounds and spoilage. During cold storage, ascorbic acid content, total phenolic content and antioxidant activity were greater in 100 and 1000 µmol l−1 melatonin treated plums than the control and other doses. Meanwhile, 1000 µmol l−1 melatonin substantially reduced decay rate, which result from significantly higher biochemical compounds. These findings suggested that especially 1000 µmol l−1 melatonin treatment may be useful technique to extend the postharvest life of plum with acceptable fruit quality.

Quality of raisins under different packaging and storage conditions

ABSTRACTWe determined the effect of different storage systems and packaging on the quality of ‘Sultana Seedless’ raisins. The fruit were packed in plastic boxes and kept under controlled atmosphere (1% O2 and 3% CO2) at 0°C and 75–85% RH for 12 months (CA), packed in vacuum bags and kept under normal atmosphere (21% O2–0.03% CO2) (NA) and packed in thin plastic bags + carton boxes and kept under ambient condition (semi-refrigeration), at 0°C and 90% ± 5 RH for 12 months (AC). Fruit kept under CA or NA had acceptable fruit quality in terms of general appearance and taste for 10 months, whereas fruit quality was unacceptable at that time under AC. Fruit under NA had less weight loss than fruit under the other conditions. Differences in skin colour were relatively small, apart from the h° values. Concentrations of ochratoxin A were generally higher with AC. External appearance and taste were better with CA and NA. As a result, raisins can be stored for 10 months with good quality in vacuum package in NA (0°C and 90% ± 5 RH) and CA (1% O2–3% CO2) at 0°C and 75–85% RH.

Influence of temperature and salinity on tomato quality of a high value commercial cultivar

The combination of mild climate and soil salinity are the main causes of the exceptional fruit quality of some “flavour varieties” such as the hybrids of the Raf tomato. If conditions during fruit growth, mainly thermal and osmotic, are not adequate, the consumer does not always gets an acceptable fruit quality. The present work was conducted to study the effect of pre-harvest factors such as temperature and salinity on the quality of a high commercial value tomato cultivar. The experiment was conducted in a 12 m2 growth chamber, equipped with a control system for temperature, humidity and pure CO2 injection. Hybrid Raf tomato 'Dumas' grafted on Lycopersicon esculentum Mill. 'Arbiore' and grown in perlite substrate were exposed to four water salinity levels (2.5, 5.5, 8.0 and 12.0 dS m-1) and four day/night temperature regimes (20/14°C; 24/14°C; 28/14°C; 30/14°C). Salinity significantly increased soluble solid content (SSC) and titratable acidity (TA), but in contrast, the effect on pH was less responsive. Fruit firmness was strongly affected by salinity and adopted an inverse relationship from 24°C. Temperature affected significantly fruit quality at 28°C, quality parameters were reduced, except TA, which showed the highest values. Statistical analysis indicates an interaction between salinity and temperature, so that the reduction of quality parameters ​​caused by the temperature was less sensitive in the higher salinity treatments. The period of fruit development (PFD) was not affected by salinity in contrast, high temperature significantly reduced it. A strong direct relationship between PFD and the firmness was also observed. No differences in fruit quality parameters as affected by the different position of the trusses were observed. This study provides useful information to adjust climate control and fertigation set-points values in the cultivation of high value commercial tomato production.

Post harvest physiological and biochemical changes in guava (cv. LUCKNOW-49) fruits harvested at two stages of maturity during low temperature storage

The present investigation was carried out at Post Harvest Laboratory, College of Horticulture, Rajendranagar, Hyderabad during Nov.-Dec. (2010 and 2011). Skin colour, fruit firmness, pectin content, pectin methyl esterase (PME) activity, respiration and ethylene evolution rates were monitored during cold storage (10±1°C and 90±5% RH) of guavas (cv. LUCKNOW-49) harvested at two stages of maturity, mature green (maximum growth of fruits is attained and skin colour changes from dark green to light green) and colour turning (skin colour turns slightly yellow from light green) treated with naphthalene acetic acid (100 and 200 ppm), gibberellic acid (150 and 300 ppm) and benzyl adenine (25 and 50 ppm). Skin colour (Hunter 'L', 'a' and 'b') increased progressively, while fruit firmness and pectin content decreased consistently with the advancement of storage period. Activity of cell wall degrading enzyme, PME declined gradually till the fruits became ripe, but increased in the over-ripe stage. Likewise, respiration and ethylene production rates also exhibited similar pattern of increase coinciding with ripe stage followed by a decline later. However, the peak in respiration rate was preceded by maximum ethylene production in guava during storage at 10±1°C. Mature green (MG) stage fruits showed promising results in delaying the physiological and biochemical changes compared to colour turning (CT) stage and among the treatments, fruits treated with BA (50 ppm) exhibited longer shelf-life and acceptable fruit quality during cold storage.

Effect of 1-methylcyclopropene on shelf life, visual quality and nutritional quality of netted melon

The effects of 1-methylcyclopropene (1-MCP) on shelf life, fruit visual quality and nutritional quality were investigated. Netted melons were treated with air (control) and 0.6 µl l(-1) 1-MCP at 25 ℃ for 24 h, and then stored at 25 ℃ or 10 ℃ for 10 days. 1-MCP significantly extended the shelf life, inhibited weight loss and delayed firmness decline of melon fruits. Ethylene production was also inhibited and respiration rate was declined. 1-MCP retarded 1-aminocyclopropane-1-carboxylic acid (ACC) increases and inhibited ACC synthase and ACC oxidase activity. Moreover, 1-MCP treatment reduced the decrease in total soluble solids and titratable acidity, as well as the decrease of the content of sugars (sucrose, fructose and glucose). These results indicated that 1-MCP treatment is a good method to extend melon shelf life and maintain fruit quality, and the combination of 1-MCP and low temperature storage resulted in more acceptable fruit quality.

Ripening physiology and quality of ‘Hass’ avocado (Persea americana Mill.) after cold storage at 1ºC

SummaryThe export of avocado (Persea americana Mill.) fruit into foreign markets has become a high priority for the South African industry due to increased competition in the European market. Some of these countries require phytosanitary treatment before access is granted. Cold disinfestation is the only suitable phytosanitary treatment available for avocado, but the fruit are generally considered to be sensitive to temperatures below approx. 5ºC. Phytosanitary disinfestation of South African avocados of acceptable fruit quality has been achieved by maintaining the pulp temperature below 2ºC for 28 d, but the effect on ripening physiology has not been determined. The effect of cold storage at 1ºC (air delivery temperature) on ‘Hass’ avocados with or without modified humidity packaging (MHP) for 28 d was examined. Compared to a conventional storage temperature of 5.5ºC for 28 d, fruit stored at 1ºC had significantly reduced rates of respiration and ethylene production, less softening, water loss, fresh weight (FW) loss, and mannoheptulose consumption measured immediately after cold storage. The use of MHP resulted in similar reductions at the conventional temperature and, when MHP was used in combination with 1ºC storage, these reductions were enhanced. Cold storage at either temperature resulted in increased cellulase and polygalacturonase activities during ripening when compared to non-stored fruit (kept at 21ºC until ripe), but no significant differences were recorded between the four cold storage treatments (i.e., 1ºC and 5.5ºC, with or without MHP) in the activities of cellulase, polygalacturonase, and pectin methylesterase during ripening. The number of days to ripen increased slightly after storage at 1ºC, but the percentage of marketable fruit was not significantly reduced. Significantly reduced FW and water losses from fruit stored under MHP resulted in significant reductions in the severity of skin spotting. The ripening physiology and quality of South African ‘Hass’ avocados were not negatively affected when fruit were stored at 1ºC for 28 d. When considered with previous results, this treatment appears to be suitable for future use.

Effects of salicylic acid and putrescine on storability, quality attributes and antioxidant activity of plum cv. ‘Santa Rosa’

Plum fruit has a short shelf life with a rapid deterioration in quality after harvest. The primary goal of this study is to investigate and compare the effect of putrescine and salicylic acid on quality properties and antioxidant activity of plum during storage. The plum fruits (cv. 'Santa Rosa') were harvested at the mature ripe stage, and dipped in different concentrations of putrescine (1, 2, 3 and 4mmol/L) and salicylic acid (1, 2, 3 and 4mmol/L), as well as distilled water (control) for 5min. The fruits were then packed in boxes with polyethylene covers and stored at 4°C with 95% relative humidity for 25days. A factorial trial based on completely randomized block design with 4 replications was carried out. The weight loss, fruit firmness, total soluble solids, titratable acidity, pH, maturity index, ascorbic acid, total phenolics and antioxidant activity at 0, 5, 10, 15, 20 and 25days after harvest were recorded. During the storage period, the weight loss, total soluble solids, pH and maturity index increased significantly while the fruit firmness, titratable acidity, ascorbic acid, total phenolics and antioxidant activity decreased significantly (P < 0.05) for all treatments. Statistically significant differences were observed between different treatments (putrescine, salicylic acid and control) in all measured parameters. The data showed that the weight loss and softening of the plum fruits were decreased significantly by the use of putrescine and salicylic acid. Also, exogenous treatments of putrescine and salicylic acid are found to be effective in maintaining titratable acidity, ascorbic acid, total phenolics and antioxidant activity in plum fruits during storage at 4°C. It was concluded that postharvest treatment of plum fruit with putrescine and salicylic acid were effective on delaying the ripening processes and can be used commercially to extend the shelf life of plum fruit with acceptable fruit quality.

Unique Fruit Development of Ornamental ‘Teapot’ Jujube

Jujube or chinese date (Ziziphus jujuba) has fruit that is developed mainly from ovary plus some nectary disk tissue, and the fruit can appear smooth or bumpy on the surface. The objective of this study was to investigate the unique fruit development of ornamental ‘Teapot’ jujube. Unlike ‘Li’ and ‘Lang’, ‘Teapot’ jujube fruit had one to five protuberances on the shoulder of the fruit and few entirely lack protuberances. The stamens of ‘Teapot’ jujube flowers were fewer in number, misplaced in location, and deformed in shape—some stamens were anthers only while others were filament only. Deformed stamens of ‘Teapot’ jujube were always anchored in the nectary disk instead of at their normal location—near the edge of the nectary disk. After bloom, the residue of stamens, nectary disk, and ovary were all constituents of the developing fruit. The deformed stamens developed into the fleshy protuberances and equaled them in number. Fruit with only two protuberances predominated, which is how the ‘Teapot’ jujube acquired its name, but the ratio among protuberance categories varied between trees. With its unique and decorative fruit shape, and acceptable fruit quality, ‘Teapot’ jujube could be used as a backyard tree, both as an ornamental and for its fruit.

VACCINIUM SPECIES OF SECTION HEMIMYRTILLUS - THEIR VALUE TO CULTIVATED BLUEBERRY AND APPROACHES TO UTILIZATION

The primary gene pool of Vaccinium species used by breeders has traditionally been the North American Vaccinium species in section Cyanococcus. Blueberries in commercial production represent several Vaccinium species and ploidies. Moreover, significant use has been made of the secondary gene pool of Vaccinium, especially in the development of southern highbush cultivars. Section Hemimyrtillus represents species that are part of the tertiary gene pool of Vaccinium. Two species of section Hemimyrtillus, native to the Portuguese islands of Madeira (Vaccinium padifolium Smith) and the Azores (Vaccinium cylindraceum Smith), have features of notable value to conventional blueberry development such as upright structure, strong growth, abundant flowering and fruiting, good self-fertility, acceptable fruit quality, inflorescence structure suited to mechanical harvesting, and repeat flowering. Vaccinium cylindraceum is deciduous, whereas V. padifolium is evergreen. Vaccinium arctostaphylos L., a native of the Caucasus region, is closely allied to V. padifolium, hybridizes freely with it, and has many similar characters, but with the valuable addition of greater cold hardiness. Initial progress has been made at incorporating these species into forms compatible with Vaccinium corymbosum L. based blueberry cultivars, and further evaluations are being made of both parental material and the derived hybrids.

Vacciniumspecies of sectionHemimyrtillus: their value to cultivated blueberry and approaches to utilization1This article is part of a Special Issue entitled “A tribute to Sam Vander Kloet FLS: Pure and applied research from blueberries to heathland ecology”.

The primary gene pool of Vaccinium species used by breeders has traditionally been the North American Vaccinium species in section Cyanococcus. Blueberries in commercial production represent several Vaccinium species and ploidies. Moreover, significant use has been made of the secondary gene pool of Vaccinium, especially in the development of southern highbush cultivars. Section Hemimyrtillus represents species that are part of the tertiary gene pool of Vaccinium. Two species of section Hemimyrtillus, native to the Portuguese islands of Madeira (Vaccinium padifolium Smith) and the Azores (Vaccinium cylindraceum Smith), have features of notable value to conventional blueberry development such as upright structure, strong growth, abundant flowering and fruiting, good self-fertility, acceptable fruit quality, inflorescence structure suited to mechanical harvesting, and repeat flowering. Vaccinium cylindraceum is deciduous, whereas V. padifolium is evergreen. Vaccinium arctostaphylos L., a native of the Caucasus region, is closely allied to V. padifolium, hybridizes freely with it, and has many similar characters, but with the valuable addition of greater cold hardiness. Initial progress has been made at incorporating these species into forms compatible with Vaccinium corymbosum L. based blueberry cultivars, and further evaluations are being made of both parental material and the derived hybrids.

Delayed harvest and cold storage period influence ethylene production, fruit firmness and quality of ‘Cripps Pink’ apple

The effects of harvest date and cold storage period on ethylene production, fruit firmness and quality of ‘Cripps Pink’ apple were investigated. Fruit were harvested from Perth Hills and Donnybrook (Western Australia) at commercial maturity (CM), 2, 4 and 6 weeks after CM prior to 0, 45, 90 and 135 days cold storage in 2003 and 2004. Delayed harvest significantly increased ethylene production, CIE values a* and C* at both locations in 2 years. Delayed harvest and extended cold storage period increased the internal ethylene production and reduced fruit firmness, soluble solids concentration: titratable acidity (SSC:TA) ratio and reduced CIE values L*, b*, h° during both years and locations. Fruit harvested 2 weeks after CM can be cold-stored for 90 days with acceptable fruit quality. If the fruit is intended to be sold fresh immediately in local markets, the harvest can be delayed up to 6 weeks after CM to harness substantially improved fruit colour with acceptable fruit quality.

Postharvest application of 1‐Methylcyclopropene modulates fruit ripening, storage life and quality of ‘Tegan Blue’ Japanese plum kept in ambient and cold storage

SummaryThe role of postharvest application of 1‐Methylcyclopropene (1‐MCP) in modulating ‘Tegan Blue’ Japanese plum fruit ripening and quality under ambient and cold storage conditions was investigated. 1‐MCP‐treated fruit (0, 0.5, 1.0 and 2.0 μL L−1) were allowed to ripen at ambient temperature in Experiment 1, while in the second experiment the fruit were kept in cold storage (0, 3 and 6 weeks) before ripening. In both experiments, 1‐MCP treatment significantly delayed (2–8 days), suppressed (30–70%) the climacteric ethylene production, maintained higher fruit firmness (34–60%), titratable acidity, L*, chroma, hue angle of fruit skin and pulp, and reduced concentrations of soluble solids, ascorbic acid, total carotenoids and total anti‐oxidants as compared to the control. 1‐MCP (1.0 μL L−1) treatment suppresses and delays the climacteric ethylene production with acceptable fruit quality during ripening at ambient temperature and is effective in extending the storage life up to 6 weeks with minimal loss of plum fruit quality.

Comportamento de clones de laranja 'Valência' na região norte do Paraná

Este trabalho teve como objetivo avaliar os clones de laranjas-doces [Citrus sinensis (L.) Osbeck] 'Valência', acesso I-93; 'Valência 718', acesso I-94, e 'Valência Late 1138', acesso I-105, enxertados sobre o limão 'Cravo' (Citrus limonia Osbeck), em relação à produção e às características físico-químicas dos frutos (acidez, sólidos solúveis totais, 'ratio', rendimento em suco, índice tecnológico e massa). As plantas estudadas fazem parte do Banco Ativo de Germoplasma de Citros (BAG-Citros) do Instituto Agronômico do Paraná - IAPAR, em Londrina. Foram utilizadas três plantas por clone, em espaçamento de 7,0 m x 6,0 m (238 plantas/hectare), conduzidas sem irrigação. As produções acumuladas das laranjas 'Valência' e 'Valência Late 1138', durante nove safras (1985 a 1994), foram significativamente superiores à da 'Valência 718'. Todos os clones apresentaram características aceitáveis de frutos, em relação à acidez, sólidos solúveis totais, 'ratio', rendimento em suco e massa do fruto, exceto para o índice tecnológico, que foi inferior na 'Valência Late 1138', não sendo observadas diferenças significativas durante o período avaliado (1986 a 1997).

Use of hot water treatment to control codling moths in harvested California ‘Bing’ sweet cherries

Preharvest gibberellic acid-treated California ‘Bing’ sweet cherries (Prunus avium L.) were treated with hot water baths (46–58 °C for 0.25–18 min), followed by hydrocooling. The fruit were then stored to simulate either air shipment or sea shipment to overseas markets, both followed by 15 h of shelf life at 20 °C. In separate experiments, cherries were also infested with codling moth larvae and subjected to similar hot water bath heating. The quality attributes showed different sensitivity to the combinations of temperature and time used for hot water bath treatment. Pitting was more common in fruit treated at lower temperatures for longer times, while stem browning was more common in fruit treated at high temperatures. Berry browning, stem color, and pitting were the quality attributes most affected by heat treatment. Browning of cherry stem color was a crucial factor in determining whether a combination of temperature and time for hot water bath treatment was successful. All cherries stored at 0 °C for 14 days to simulate sea shipment were of unacceptable quality after shelf life. Hot water bath treatments that provided 100% codling moth mortality and maintained overall acceptable fruit quality were very limited and included treatments at 50 °C for 10 min and at 54 °C for 6 min. Delaying the hot water bath treatment after fruit harvest, even if the cherries were kept at 0 °C, resulted in a greater loss in fruit quality compared with those treated on the harvest day. Using hot water baths as a quarantine treatment for codling moths (Cydia pomonella) on sweet cherries may be feasible if fruit are air shipped at 5 °C for 2 days, but not suitable if fruit are sea shipped at 0 °C for 14 days.