Percentage Of Marketable Fruit Research Articles

Effect of Plant Density on Mechanical Harvest Efficiency of New Mexico Pod-type Green Chile Pepper

Summary. New Mexico green pod-type chile (Capsicum annuum) has significant importance as a vegetable crop. The cultivation and trade of New Mexico pod-type green chile are culturally significant within New Mexico (USA) and contribute to the state’s economy by providing income and employment to farmers and through supporting industries. However, because of the high cost and limited availability of labor, New Mexico pod-type green chile acreage has declined. Traditionally, New Mexico pod-type green chile is hand-harvested when the fruit are full-size but physiologically immature. To preserve and expand the production of New Mexico pod-type green chile, the adoption of mechanical harvest technologies is essential. In 2015 and 2016, experiments were conducted at New Mexico State University’s Los Lunas Agricultural Science Center (Los Lunas, NM, USA) to examine the effects of increased planting density on New Mexico pod-type green chile fruit size, plant architecture, and mechanical harvest efficiency. Two commercial New Mexico pod-type green chile cultivars, NuMex Joe E. Parker and AZ-1904, were direct-seeded on 17 Apr 2015 and 14 Apr 2016. On 11 Jun 2015 and 14 Jun 2016, three plant density treatments were implemented at 39,000 (high), 23,000 (medium), and 15,000 (standard) plants/acre. Before harvest, plant measurements, including height, width, height to first bifurcation, stem diameter, and number of lateral basal branches, were obtained. Plots were mechanically harvested using an inclined double helix harvester, and harvested material was sorted into marketable green fruit, machine-broken fruit, and nonpod plant material. Fruit measurements, including fruit weight, width, length, pericarp thickness, and number of locules, were obtained. Both cultivars exhibited a 9% increase in height to bifurcation accompanied by fewer basal branches grown at high density. Plant density did not significantly affect the fruit length, width, number of locules, and pericarp thickness. Plants grown at high density had an increased percentage of marketable fruit, with ‘NuMex Joe E. Parker’ having a higher percentage of marketable green fruit compared to ‘AZ-1904’. The results demonstrated that an increase in planting density in production fields to 39,000 plants/acre coupled with cultivar selection enhanced efficiency in a mechanical harvest system.

Assessing the impact of despination and wax application on long-term cold stored cactus pears

Glochids and spines on cactus pears represent the main constraint that limit cactus pear consumption, thus their elimination is of pivotal importance for commercialization. Their removal causes abrasions and a reduction of epicuticular wax, which increase mass loss and microbiological spoilage. To mitigate the negative impact of glochids removal, in this study, ‘Gialla’ cactus pears of the second bloom, after despination through rotating brushes, were sprayed with two coating materials: Citrashine or Protégé at 33, 50 or 100%. Fruit were then stored at 20 °C for 1 week or at 6 °C for 4 or 8 weeks followed by 3 or 7 d at 20 °C to simulate marketing conditions. Weight loss, overall appearance and decay incidence were significantly higher in despined fruit compared to control fruit and coated fruit. When applied at 33% Protégé coating showed an overall beneficial effect that contributed to reduce mass loss, decay incidence and to improve fruit appearance without affecting chemical or sensory quality. Protégé at 50% and 100% reduced weight loss but resulted phytotoxic and worsened fruit appearance and had a negative impact on the percentage of marketable fruit, besides increasing the degradation of juice chemical compounds and altering sensory attributes. Citrashine had a good impact on preventing decay slowing down mass loss and overall appearance but altered the chemical and the eating quality as Protégé coating when applied at 50% or 100%.However, in fruit directly placed in simulated marketing conditions at 20 °C, despination neither altered fruit quality nor reduced fruit marketability. Thus, replacement of epicuticular waxes lost by despination with coatings can be beneficial for long term storage of cactus pear, provided that the applied material is not phytotoxic and does not impair the fruit gas exchange.

Field Tests of Three Alternative Insecticides with Protein Bait for the Development of an Insecticide Rotation Program to Control Melon Flies, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae)

Simple SummaryMelon flies in Hawaii have developed high levels of resistance to a widely used insecticidal bait containing the active ingredient spinosad. Since farmers relied heavily on this product and have few alternatives, we tested three other insectides mixed with a bait spray called Nu-Lure. The three products (Agri-Mek SC, Mustang Maxx, and Malathion 5EC) were all found to be effective in either decreasing melon fly numbers or suppressing the growth of the population in the field. When used one-by-one in rotation for two weeks per product at one-week intervals on a commercial zucchini farm, melon fly populations were dramatically reduced and the yield of zucchinis harvested was substantially increased.High levels of resistance to the spinosad-based insecticidal protein bait GF-120 have been detected in some populations of melon fly, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae), in Hawaii in 2017. To provide cucurbit farmers in Hawaii with alternative insecticides, we field-tested the effectiveness of Agri-Mek SC (a.i., abamectin), Mustang Maxx (a.i., zeta-cypermethrin), and Malathion 5EC (a.i., malathion), added to a protein bait spray (Nu-Lure Insect Bait). The insecticide and protein bait combinations were applied to the roosting plants of Z. cucurbitae around the perimeter of the cucurbit fields at one-week intervals. When individually tested, all three insecticides in combination with protein bait significantly reduced or suppressed the numbers of female flies caught in torula yeast traps. A two-week rotation of weekly applications of the three insecticides and GF-120 significantly reduced Z. cucurbitae numbers on a commercial zucchini farm on Maui. The percentage of marketable fruits harvested increased from 51% to 98% after implementing the insecticide rotation. Our findings will be used to provide cucurbit farmers with additional products to control Z. cucurbitae. The future focus will be on educating cucurbit farmers to use the insecticide rotation strategy to prevent or delay resistance development.

Harvest of Southern Highbush Blueberry with a Modified, Over-the-Row Mechanical Harvester: Use of Soft-Catch Surfaces to Minimize Impact Bruising

Harvest of fresh market, southern highbush blueberries (SHB) is labor intensive and costly, leading to a demand for alternative harvest methods. Recent research has shown potential for mechanically harvesting blueberries with minimal bruising by using a modified over-the-row (OTR) harvester. For two harvests, SHB cultivars Optimus and Vireo were either hand-harvested (HH) or mechanically harvested (MH) by two commercial harvesters, one unmodified with standard hard-catch surfaces (HCS) or by the other modified with soft-catch surfaces (SCS). For Harvest 1, fruit from all harvest methods were hand-sorted into the following categories: blue fruit (marketable), red fruit, green fruit and culls. Samples from each cultivar and treatment were then held at 24 °C overnight, and the following day firmness and impact bruise severity were determined. Harvest 2 had identical harvest treatments; however, the fruit were sorted on a commercial packing line prior to packing in clamshells (n = 16). A subsample was held overnight as in Harvest 1 for bruise severity rating, while the remaining fruit were stored at 1 °C for 14 days (d). Although percent marketable fruit was more affected by cultivar than harvest method, determination of bruise severity revealed the benefit of harvest with SCS over HCS for both cultivars. The former had 16–26% severe bruising, compared to 27–40% for the latter; HH had 1–4%. During storage, HH fruit remained firmer than HCS and SCS, which were similar. After 14 d, firmness for “Optimus” was 239 N (HH), 157 N (HCS and SCS) and for “Vireo” it was 189 (HH), 155 N (HCS and SCS). Fruit weight loss increased during storage (1.1–4.4%), but there was no difference due to catch plate surface. SSC, TTA and Ratio were not affected by catch surface type or storage period within cultivar. Using modifications such as “soft” catch surfaces on currently available OTR harvesters reduces impact bruise damage; however, impacts incurred during commercial packing operations can negate this effect. MH for fresh market blueberries may provide an economical alternative for blueberry growers; however, with current technology, the fruit should be utilized within a week of harvest.

Effect of Different Edible Coatings on Postharvest Quality of Mandarin Orange (Citrus reticulata Blanco)

Although Nepal produces a large amount of mandarin it faces huge postharvest losses due to improper postharvest practices. Treating fruits with different edible coatings can minimize postharvest losses. The experiment was carried out in the horticulture lab of Prithu Technical College, Dang, Nepal to evaluate the effects of different edible coating materials on the postharvest quality of mandarin. The experiment was laid in Complete Randomized Design (CRD) with three replications and seven treatments in each replication. Mandarins were coated with different edible coating materials i.e. paraffin wax (100%, 75% and 50%), mustard oil, Aloe vera, turmeric paste and control (non-coated). After coating with different edible materials, mandarins were kept at ambient room conditions (18±2℃ and 52.41±14.35%). The lowest physiological loss in weight at 7, 14and 21 days was recorded in mandarin coated with 75% paraffin wax which was 3.10%, 4.83% and 10.33%, respectively. The highest titratable acidity (0.68%), juice content (46.33%) and marketable fruit percentage (81.73%) were recorded in 75% paraffin wax. The highest total soluble solid (14.00 ˚Brix) was recorded in control. Based on the result obtained from our research, it is suggested to use 75% paraffin wax for the storage of mandarin at ambient room conditions (18±2℃ and 52.41±14.35% RH) as it gives a high percentage of marketable fruits and juice content and also minimizes the physiological loss in weight.

Impact of organic manure on fruit set, fruit retention, yield, and nutritional status in pomegranate (Punica granatum L. "Wonderful") under water and mineral fertilization deficits.

This research was conducted on mature pomegranate (Punica granatum L. “Wonderful”) trees growing at a site located in North Coast, Matrouh Governorate, Egypt. The aim was to investigate the impacts of different irrigation regimes in combination with different fertilizer regimes on the fruit set, fruit retention, yield, and nutritional status of the trees. The experimental factors were arranged in a split-plot design, with four replicates per treatment combination. The results indicated that all of the characteristics measured, including leaves nutritional status, percentages of fruit set, fruit drop, fruit retention, fruit cracking, fruit sunburn, and marketable fruit, and yield were significantly affected by the interaction between the irrigation treatment which denoted by percentages of reference evapotranspiration (ETo) and fertilizer regime. The application of 75% mineral fertilizer + 25% organic manure under deficit irrigation of 80% ETo increased the yield by an average of 18.23% over the 2 years compared with 100% mineral fertilization under full irrigation, while 50% mineral fertilizer + 50% organic matter under 80% ETo gave the maximum percentage of marketable fruit (86.23% and 86.84% in 2018 and 2019, respectively). The maximum water use efficiency was obtained with the 80% ETo treatment combined with 75% mineral fertilizer + 25% organic manure in both seasons with values of 9.69 and 10.06 kg/m3 applied water, respectively. These results demonstrate that under the field conditions at the experimental site, the fruit set and retention could be improved by applying a reduced amount of mineral fertilizer in combination with organic manure and less irrigation water.

Bell pepper production under saline stress and fertigation with different K+/Ca2+ ratios in a protected environment

Bell peppers are sensitive to salinity; therefore, it is necessary to find alternatives to reduce saline stress. An experiment was conducted in a greenhouse at Federal Rural University of the Semi-Arid Region, in Mossoró, Rio Grande do Norte State, Brazil, to evaluate the effects of salinity and K+/Ca2+ ratios on bell pepper production. The experimental design consisted of randomized blocks in a 5 x 4 factorial scheme with four replicates, corresponding to five K+/Ca2+ ratios (F1 = 3.3/1, F2 = 2.8/1, F3 = 2.2/1, F4 = 1.8/1, and F5 = 1.5/1) and four salinity levels in the nutrient solution using NaCl (1.75, 3.25, 4.75, and 6.25 dS m-1). The following parameters were evaluated: the number of fruits (total, marketable and unmarketable), the mean weight of fruits (marketable and unmarketable), fruit production (total, marketable and percentage of marketable fruits) and a salinity tolerance index. Generally, nutrient solution enrichment with K+ or Ca2+ did not cause significant increments in bell pepper yield. The fertigation treatments F2, F3, and F5 led to a higher bell pepper tolerance to salinity, allowing waters with higher salt concentrations to be used without causing a reduction in the yield.

Sensitivity analysis of the precooling process of strawberry: Effect of package designing parameters and the moisture loss.

Strawberry is one of the most perishable fruits, and precooling of strawberry increases the percentage of marketable fruits. To assess the sensitivity of strawberry cooling uniformity with respect to package vents and tray design, the previously proposed modified parallel airflow system (MPAS) was modified and a sensitivity analysis was conducted in this paper. Some improvements in homogeneous strawberry precooling process were made to give improved parallel airflow system (IPAS). To evaluate its performance, the cooling process of strawberries was simulated using the mathematical models of heat, momentum, and mass transfer, which were validated experimentally. Results showed that the IPAS was able to distribute cold air uniformly throughout the packages. A difference of 0.1°C was observed between the average fruit temperatures of the packages after 3 hr of cooling. Therefore, the cooling process of strawberry could be done at lower airflow rate, cooling time, and heterogeneity. In addition, the precooling process of strawberry was studied considering the moisture loss during the cooling process and comparing the data with the models without this term. The results indicated that the moisture loss of strawberries during the cooling process is not negligible and the cooling rate increased and the cooling time decreased (31%) by considering this term in the modeling. However, the moisture loss did not affect the heterogeneity of cooling process.

Fertilization with monoammonium phosphate in the production of Formosa ‘Tainung-01’ papaya in the potiguar semiarid

The achievement of good productivity and quality of fruits is directly associated with a balanced fertilization, in which phosphate fertilizers have an important role in the agricultural production system. In this context, this work aimed to evaluate the effect of doses of monoammonium phosphate in ground fertilization and associated with the topdressing in the production of the Formosa “Tainung-01” papaya. The experimental design was in complete randomized blocks, in an split plots outline, having as main factor four fertilizer doses in ground fertilization (0; 80; 160, and 250 kg ha-1 of monoammonium phosphate [MAP]) and, as a sub-portion, two fertilizers in topdressing (20 kg ha-1 of Cosmofert® + 45 kg ha-1 of MAP” and “90 kg ha-1 of MAP). The harvesting began in the eighth month and extended until the 12th month after transplanting of the seedlings. All fruits of five plants per experimental unit were collected and classified. The number of fruits, the production per plant, the yield, and the percentage of marketable fruits were evaluated. The ground fertilization with the monoammonium phosphate did not influence the production of Formosa 'Tainung-01' papaya fruits exclusively destined to the domestic market. When the production is destined to the external market, a dosage of 74.0 kg ha-1 of monoammonium phosphate can be used in ground fertilization.

Effect of micrifertilizers of the Activ Harvest line on the yields of tomatoes

The influence of Active Harvest microfertilizers with different compositions on the yield of four tomato varieties was studied. It was found that the variety Red Giant is characterized by the highest yield and the best reaction to microfertilizers treatment.. The maximum percentage of marketable fruits was obtained from large-fruited varieties of tomatoes. A more noticeable effect on fruit yield and marketability was recorded in active fertilizers Active Harvest Oil. Key words: tomatoes, Pink flamingo, Solaris, Red giant, Pink giant, microfertilizers, Active Harvest Oilseeds, Active Harvest Prime, yield, marketability.

Parthenocarpic Cucumber Cultivar Evaluation in High-tunnel Production

Fresh-consumed parthenocarpic cucumbers (Cucumis sativus) are a popular and high-value crop sold in local food markets. The parthenocarpic plant characteristics and climbing growth habit make cucumbers an ideal crop for high-tunnel production. Major types of parthenocarpic cucumbers include Beit alpha and mini, Dutch greenhouse, American slicer, and Japanese. Information regarding yield performance, plant growth, and disease resistance of the four types grown in high-tunnel conditions is limited. In this study, 16 parthenocarpic cucumber cultivars from the four major types were evaluated in high tunnels at three locations in Indiana and Illinois during Spring 2018. Plants were pruned to a single stem that was supported on a string. At all locations, the cultivars that had the most total yields were Beit alpha and mini, although their total yields were not always significantly higher than that of all the others. However, Beit alpha and mini cucumbers had high percentages of unmarketable fruit, mainly because of insect feeding damage and mechanical injuries on the skins that led to scarred fruit. Dutch greenhouse cultivars had relatively lower marketable yields at two of the three locations where there was a high percentage of misshaped fruit. ‘Tasty Green’ Japanese cucumber consistently had the lowest yields at all three locations. This cultivar also produced the most side shoot growth and, therefore, more pruning waste. The Japanese types ‘Tasty Jade’ and ‘Taurus’ had yields comparable to those of other cultivars, and they were more tolerant to two-spotted spider mites (Tetranychus urticae). However, ‘Tasty Jade’ was the cultivar most susceptible to powdery mildew (Podosphaera xanthii and Golovinomyces cichoracearum). ‘Corinto’ American slicer cucumber had relatively high yields at two of the three locations. This cultivar also had the highest percentage of marketable fruit. Information provided in the study is readily useful for growers using high tunnels when selecting parthenocarpic cucumber cultivars. It is also valuable for seed companies wishing to breed new cultivars adaptive for high-tunnel production.

Effect of Shaking Location and Duration on Mechanical Harvesting of Fresh Market Apples

Abstract. With adopting the modern high-density tree architectures, localized shake-and-catch harvesting is becoming more promising for fresh market apples. To investigate the shaking inputs for an effective harvesting system, a multi-tier shake-and-catch harvesting platform was developed and evaluated in a commercial orchard. The platform composes of a shaker and two three-tier catching surfaces. Performance test was conducted in ‘Jazz’ apple trees trained to a vertical fruiting wall architecture (two horizontal branches at each tier). Two harvesting sections were defined in the test trees, namely, Section I - two neighboring branches at the same tier from two adjacent trees; and Section II - two branches at the same tier of a tree. For Section I, shaking was applied to the middle of each branch (location P1), and for Section II, shaking was applied at the location close to the trunk (location P2). Shaking frequency was set to 20 Hz, and two shaking durations (i.e., 5 and 2 s) were used. In the test, the catching angle relative to the horizontal plate was set to 15°. The results indicated that the fruit removal efficiencies (2nd to 4th tiers of trees were used in the analysis) were 76.6% and 78.1% for shaking at middle of each branch in 2 and 5 s shaking, respectively; those numbers were 86.3% and 89.5% for shaking at location P2. The percentage of marketable fruits were 89.7% and 90.6% for the Section I shaking in two durations, and 84.5% and 84.4% in the Section II shaking. Overall, this study revealed that 2 s shaking duration is sufficient to remove majority of fruits in the tested variety, and the section II shaking had higher overall fruit removal efficiency but also caused slightly more fruit damage. Keywords: Fresh market apples, Fruit quality, Fruit removal efficiency, Mechanical harvesting, Multi-tier shake-and-catch.

Understanding the effects of slip pruning on pineapple fruit quality

Pineapple fruit quality is important especially when fruits are exported to international markets. Fruits should meet minimum requirements such as a weight of at least 0.7 kg, a ratio between the crown length and infructescence (fruit without the crown) length ranging from 0.5 to 1.5, and a Brix of at least 12. Most pineapple producers in Benin face difficulties in meeting these requirements and thus a very low fraction of the produce is exported. Pruning of pineapple slips has been explored as a means to improve fruit quality but no consistent effects were found. In this study slips were pruned from plants with small and large infructescences and the effects on fruit characteristics were determined. Two on-farm experiments were conducted in commercial fields in Benin using a cultivar locally known as Sugarloaf. Split-plot experiments were used with main plots pruned two or three months after inflorescence emergence and split plots having all slips or no slips pruned. The length of the infructescence on the day of pruning was used to characterise plants as least or most advanced. Fruit attributes measured at harvest were fruit (infructescence + crown) weight and length, and total soluble solids. Fruit and infructescence lengths and weights at harvest were positively related to the length of the infructescence at pruning (IL), and the ratio crown: infructescence length at harvest was negatively related to the IL. Pruning of slips, however, did not increase fruit and infructescence weight and length, nor the total soluble solids, in any of the treatments. Therefore, slip pruning is not an option to increase pineapple fruit and infructescence lengths and weights or the percentage of marketable fruits in Benin.

Plant vibration of american pepper cultivars for fruit production in protected environment with and without closed sides

The aim of this research was to evaluate plant vibration for fruit and seed production of american pepper in greenhouse with open and closed sides. The experiment was carried out at Fazenda Experimental da Unesp/FCA located in the municipality of São Manuel-SP. Six treatments were carried out, in a split plot design, two plots with plant vibration or without plant vibration and three subplots with cultivars ('Dirce', 'Dínamo' and 'Doce Comprida'). Plants were vibrated by shaking the wire where the stake was fixed, manually, for about 5 seconds, twice a day. Randomized block design with three replications were used. The same experiment was performed in two environments: with and without closed sides with screen. The traits evaluated were: mass of fruit and total and marketable number of fruits (no visible defects) per plant; percentage of marketable fruit; mass, diameter and length of the fruit; mass and number of seeds per fruit; and plant height. The fruit production was higher in the environment with sides closed, with 24 marketable fruits per plant whereas in the open environment, 7 marketable fruits. American pepper plant vibration did not affect production, length, diameter and average mass of the fruits. Exceptionally for the cultivar 'Doce Comprida', a higher seed production per fruit was obtained in open environment in the absence of plant vibration, in comparison to close environment, with average of 259 and 126 seeds per fruit, respectively. American pepper plant vibration did not affect production, length, diameter and average mass of marketable fruits

Postharvest Ripening and Quality of Guatemalan-West Indian Avocado Hybrids under Simulated Commercial Shipping Temperatures Following Treatment with Aqueous 1-Methylcyclopropene

Two Guatemalan-West Indian avocado (Persea americana) hybrids (‘Monroe’ and ‘Booth 8’) were treated with an aqueous formulation of 1-methylcyclopropene (1-MCP) to determine effects on ripening and quality during storage simulating commercial shipping temperatures. Fruit harvested at preclimacteric stage were immersed in aqueous 1-MCP at 75 μg·L−1 (1.39 mmol·m−3) or in deionized water for 1 minute, stored at 10 °C for 14 days, and then transferred to 20 °C until ripe. Respiration rate, ethylene production, softening, and change in epidermal hue* angle were delayed and/or suppressed in both cultivars exposed to 1-MCP, although effects were less pronounced with Booth 8. Hue* angles for 1-MCP-treated ‘Monroe’ fruit had the highest values (darkest green peel color) of all treatments at full-ripe stage (hue* angle = 117). For control and treated ‘Monroe’ fruit respiration peaked on days 15 and 21, while ethylene production from both treatments peaked on day 16. Respiration and ethylene production peaked on day 16 for both control and 1-MCP–treated ‘Booth 8’ fruit. Fruit treated with 1-MCP consistently showed diminished respiration and ethylene peaks. Days to full-ripe stage were unaffected by treatment. ‘Booth 8’ fruit from both treatments were considered ripe (15 N whole fruit firmness) after 17 days; however, only 8% of control fruit were marketable, whereas 58% of 1-MCP-treated fruit were marketable, based on subjective appearance ratings using the Jenkins–Wehner score. The development of peel blemishes during storage was the primary cause of unmarketable fruit. ‘Monroe’ control and 1-MCP–treated fruit were soft after about 22 days and were significantly more marketable (control 70% and 1-MCP 85%). Avocados treated with 1-MCP ripened over a longer period than control fruit but maintained a higher percentage of marketable fruit.

Postharvest responses of red and yellow sweet peppers grown under photo-selective nets

Postharvest responses of red (‘HTSP-3’) and yellow (‘Celaya’) sweet pepper fruit yield, quality parameters and bioactive compounds (to three types of photo-selective nets and a standard black net) were investigated in this study. Red and yellow peppers produced under the black net retained higher β-carotene, lower total phenolic contents and showed deep red and orange colour after storage. Both peppers produced under the pearl net retained a higher ascorbic content, antioxidant scavenging activity, fruit firmness and also reduced weight loss after storage. Red and yellow peppers grown under pearl and yellow nets resulted in a higher percentage of marketable fruit, after storage. Red pepper grown under the yellow net showed a higher number of odour active aroma compounds in the fruit, while black nets significantly affected the synthesis of odour active aroma compounds during storage. Sensory analysis indicated a preference for red pepper fruits after storage from plants grown under pearl nets.

Greenhouse Evaluation of Melon Rootstock Resistance to Monosporascus Root Rot and Vine Decline as Well as of Yield and Fruit Quality in Grafted ‘Inodorus’ Melons

Melons (Cucumis melo L.) are generally grafted onto Cucurbita rootstocks to manage soilborne pathogens such as Monosporascus root rot and v ine decline (MRR/VD) and Fusarium wilt. However, g rafting onto Cucurbita rootstocks reportedly results in the reduction of fruit quality. In this study, the resistance to MRR/VD, yield, and fruit quality of melons grafted onto melon rootstocks were evaluated under greenhouse conditions. Eight melon rootstocks (R1 to R8) were used and the inodorus melon 'Homerunstar' was used as scion. Melon rootstocks R1 to R6 were selected based on resistance to MRR/VD under greenhouse conditions. Non-grafted 'Homerunstar' and plants grafted onto squash interspecific hybrid 'Shintozwa' rootstock (Cucurbita maxima D. <TEX>${\times}$</TEX> C. moschata D.) served as controls. Grafted melons were cultivated in the greenhouse infested with Monosporascus cannonballus during two growing seasons (summer and autumn). The responses to MRR/VD, yield, and fruit quality differed depending on the rootstocks and growing season. The melons grafted onto 'Shintozwa' exhibited less severe disease symptoms and higher survival rates than non-grafted melons in both seasons. While the melon rootstocks in the summer cultivation did not increase the survival rate compared to non-grafted melons, the melon rootstocks R1 and R2 in the autumn cultivation led to higher survival rates. The melon rootstocks resistant to MRR/VD increased the percentage of marketable fruits and marketable yields. Grafting onto the melon rootstocks caused little or no reduction of fruit quality such as low calcium content, fruit softening, and vitrescence, especially in lower-temperature autumn season. Accordingly, these results suggest that grafting onto the melon rootstocks may increase the tolerance to MRR/VD and the marketable yield without a reduction of 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.

Effect of Pre-Cooling on Post Harvest Life of Mango (Mangifera Indica L.) CV. Kesar

An experiment was carried out to study effect of pre-cooling on post harvest life of mango cv. Kesar at the Post Graduate Laboratory of the Department of Horticulture, Junagadh Agricultural University, Junagadh. The results of the study indicated that mango fruits treated with different pre-cooling treatment showed lower and slower rate in physical and chemical changes than control fruits. The fruits treated with pre-cooling at 8oC for 8 hr proved to be most effective with respect to more number of days taken to ripe (11.50), longer shelf life (17.49 days), lower spoilage (20.55 %) and higher percentage of marketable fruits (55.48 %) and recorded less physiological loss in weight (21.59 %) and more firmness of fruits (0.79 kg cm -2 ) at 20 th days after storage. The treatment was also found promising for slower increase in TSS, reducing sugar and total sugar, while slower decrease in ascorbic acid and acidity during storage. The organoleptic rating with regard to colour, taste and overall acceptability was also found significantly higher in pre-cooling at 8oC for 8 hr treated fruits.

Application of β-naphthoxyacetic acid ( β-NOA) improves fruit yield and marketable quality in out-of-season cherry tomatoes (Solanum lycopersicum L. var. cerasiforme (Dunal) D. M. Spooner, G. J. Anderson and R. K. Jansen) cultivated in unheated greenhouses in the Mediterranean Basin

SummaryThe effects of truss vibration, and the application of β-naphthoxyacetic acid ( β-NOA) to flowers, on fruit-set, total and marketable yields, and fruit quality were studied in two cherry tomato [Solanum lycopersicum L. var. cerasiforme (Dunal) D. M. Spooner, G. J. Anderson and R. K. Jansen] hybrids ‘Conchita F1’ and ‘Cherelino F1’, grown in an unheated plastic greenhouse during the Winter/Spring and Spring seasons in Southern Greece. Fruit-set was high in the Winter/Spring crop but, due to unfavourable conditions (i.e., night-time temperatures below 10ºC, which impaired microsporogenesis, pollination, and fertilisation), most fruit contained few seeds, were small and unmarketable. Although both truss vibration and β-NOA significantly increased mean fruit weights, and total yields, in both cultivars, the application of β-NOA gave the greatest increase in mean fruit weight and percentage of marketable fruit. In contrast, in the Spring crop, neither treatment affected the number or weight of fruit per plant because the climatic conditions were more favourable for pollination and fertilisation. The application of β-NOA did not adversely affect fruit quality, as previously reported in large-fruiting tomato cultivars. β-NOA did not induce any malformation or puffiness in the fruit and, while these seedless fruit showed higher dry mass percentages, higher total soluble solids contents, and lower titratable acidity levels than seeded tomato fruit, their colour, firmness, sugar, and phenolics contents were not affected. Conditions that are unfavourable for fruit set frequently occur in unheated greenhouses in the Mediterranean Basin during the Winter and early Spring; therefore, we conclude that the application of β-NOA to the flowers of cherry tomato at that time will ensure higher yields, better market quality, and higher market returns.