The Effects of Light Intensity,Day Temperature and Water Supply on the Fruit-Ripening Disorders and Yield of two Varieties of Tomato

A study was made of the effects on fruit-ripening disorders and crop yield of shaded and unshaded glasshouses maintained at both high and low daytime temperatures (80° F. (26 ? 5° C.) and 65° F. (18 ? 3° C.)), in which were grown two varieties of tomatoes (Potentate and Ware Cross) at two levels of watering.

Shading the glasshouses reduced the proportion of non-uniformly coloured fruit at the high temperature. At the low temperature, shading reduced the proportion in i960 but there was no effect in 1959. Light watering reduced the proportion of non-uniformly coloured fruit in the first year but it had little effect in the second year. The variety Ware Cross bore approximately 10% fewer non-uniformly coloured fruit than did Potentate in both years.

Shading the glasshouses reduced yield in both years, the decrease being greater (62%) in the very dull year of i960 than it was (40%) in the very sunny year of 1959. The house at the low day temperature yielded a 30% greater weight of crop than the warmer house. In both years the heavily watered plants yielded more than the lightly watered plants because of an increase in mean fruit size. Potentate and Ware Cross yielded similar weights of crop in both years but Ware Cross bore more fruits and had a smaller mean fruit size.

The gross cash return obtained in 1960 was reduced by shading the glasshouses, by maintaining a high day temperature and by growing the variety Potentate as opposed to Ware Cross. The differences in the watering regimes employed had little effect on the cash return obtained.

By assuming that yield and quality have simple mathematical relations with degree of shading, the profitability of shading is discussed. It is shown that shading is not likely to be profitable.     

The Response to CO2 Enrichment of Capillary-Watered Single-Truss Tomatoes at Different Plant Densities and Seasons

CO₂ enrichment advanced the date of first anthesis, promoted earlier cropping and shortened the duration of harvest for single-truss tomatoes sown in December and, to a lesser extent, for those sown in July. It also prevented arrested development of the flowers of a December-sown crop growing in poor light.

CO₂ caused increases in marketable fruit yield that were greatest for a mid- July sowing and least for a mid-December sowing. The increases obtained from plants sown in mid-December were independent of population density. For a mid-July sowing the increases in yield of ripe marketable tomatoes were 33% and 17% at population densities of 10 and 25 plants/m² respectively. Increases in total marketable fruit weight caused by CO₂ resulted from an increase in the number of fruits attaining marketable size and an increase in the average weight of individual fruits.

Some of the advantages of producing fruit on single-truss tomatoes grown in shallow capillary-watered beds are mentioned.     

The Effects of Temperature,Extent of Evaporation,and Restriction of Ventilation on the Storage Life of Tomatoes

The storage life of English glasshouse tomatoes is generally terminated by the onset of rotting which at temperatures above 50° F. (10° C.) generally starts from the calyx. As the temperature of storage is reduced below 50° F. the skins of tomatoes become increasingly susceptible to fungal invasion.

Storage at 59° F. (15° C.), under conditions of restricted ventilation in controlled-atmosphere storage which allow exposure to more than 5% CO₂, , also renders the skins of tomatoes susceptible to fungal infection.

The establishment of infection is also greatly influenced by the extent of evaporation, i.e. by the humidity of the storage atmosphere.

The conditions for the storage of tomatoes and the precautions to be observed in prepackaging are discussed in the light of these effects.     

Post-harvest putrescine treatments extend the storage-life of apricot (Prunus armeniaca L.) ‘Tokhm-sefid’ fruit

Summary

The aim of this study was primarily to increase the storability of apricot which is normally a very short storage-life stone fruit. Polyamines are well-known to improve the storability of many horticultural crops. The effect of exogenously applied putrescine on the post-harvest storage-life of apricot (Prunus armeniaca L.) ‘Tokhm-sefid’ fruit at 2°C was therefore investigated. The rate of ethylene production, fresh weight (FW) loss, tissue firmness, soluble solids content (SSC), titratable acidity (TA), and the pH of fruit were determined 5, 10, 15, 20 and 25 d after the beginning of storage. Overall, the application of putrescine caused a reduction in ethylene production, as well as an increase in fruit flesh firmness. SSC and pH were reduced, and TA was increased in putrescine-treated fruits. The loss of fruit FW was affected by putrescine in a concentration-dependent manner. Thus, fruit treated with higher concentrations of putrescine showed lower FW loss.     

Storage performance of clementines treated with hot water,sodium carbonate and sodium bicarbonate dips

Summary

The potential of using hot water (2.5 min at 45°C), 2% sodium carbonate or 2% sodium bicarbonate solutions alone or combined with hot water, for control of Penicillium digitatum (green mould) was investigated on commecially ripe clementines. The effect of such treatments on the post-harvest storage life of clementines was determined during two months analysing weight loss, increase in rind deformation and internal maturity. Carbonate and bicarbonate solutions effectively control green mould during storage but hot water does not. Compared with the control and hot-water treated fruits, clementines treated with carbonate and, to a lesser extend with bicarbonate, showed higher weight loss and lower firmness during storage. In contrast, lower increase in ripening index was found when the fruits were treated with carbonate or bicarbonate. Fruits treated with hot water alone or combined with carbonate exhibited no change in ripening during the first month of storage. Rinsing the fruit significantly reduces weight and firmness loss in the fruits treated with carbonate and bicarbonate, but did not change the ripening index. The primary finding of this work was that carbonate and bicarbonate treatments might significantly increase the loss in weight and firmness during storage. Rinsing the fruit immediately after treatment appeared to be a simple solution to avoid these losses in quality.     

Effect of storage temperature on ripening and quality of custard apple (Annona squamosa L.) fruits

Summary

The effect of storage temperature on ripening, shelf life and chemical composition of custard apple (Annona squamosa L.) fruits stored at 10,15,20 and 25°C was studied. The safe range of storage temperature was found to be between 15 and 20°C, with maximum shelf life at 15°C. The ripening of fruits was observed on days 4, 6 and 9 of storage at 25,20, and 15°C respectively. The colour of the pulp, texture, taste and flavour of ripe fruits held at 25 and 20°C were superior followed by fruits stored at 15°C. At 10°C, the fruits became hard with surface blackening, messy pulp and less sweetness. The major changes during ripening were a continuous decrease in fruit firmness and starch content and a continuous increase in TSS and sugars, the changes being more rapid at 25 and 20°C than at 15 and 10°C. The acidity and ascorbic acid contents increased slightly during the initial stages of ripening followed by a decline, in the fruits stored at different temperatures. Custard apple fruits stored at 25 and 20^CC had a clear climacteric peak whereas those stored at 15 and 10°C did not show any distinct rise in respiration rate. Ethylene peak (2.40 µl kg^–1 h^–1) coincided with the respiratory climacteric at 25^CC storage, corresponding with the peaks in TSS, sugars, ascorbic acid and acidity.     

Use of low-pressure storage to improve the quality of tomatoes

Freshly harvested vine-ripened tomatoes (Solanum lycopersicum cv. Neang Pich) were stored at low pressure (4 kPa) at 10°C for 11 days with 100% RH. Fruit quality was examined upon removal and after being transferred to normal atmosphere (101 kPa) at 20°C for 3 days. Weight loss was significantly lower in fruits which were stored at low pressure (4 kPa) than in fruits that were stored at regular atmosphere (101 kPa) at 10°C. Fruits that were stored at low pressure (4 kPa) reduced calyx browning by 12.5%, and calyx rots by 16%, compared to fruits that were stored at regular atmosphere (101 kPa) at 10°C. Fruit firmness was not significantly different between fruits stored at low pressures (4 kPa) and the normal atmosphere (101 kPa), with an average firmness of 14 N after fruits were stored at 10°C for 11 days. There was no difference in the SSC/TA ratio. The results suggest that a low pressure of 4 kPa at 10°C has potential as an alternative, non-chemical postharvest treatment to improve tomato quality during storage.     

Fruit-Thinning Effects on the Development and Storage Quality of Cox’s Orange Pippin Apple Fruits

Fruit-thinning treatments were applied in the three seasons 1963–65 to Cox trees to investigate the relationships between leaf : fruit ratio, fruit size, cell volume and cell number, and the incidence of rotting and disorders following air storage at 2·8° C. (37° F.) and o° C. (32° F.). Progressively more severe thinning was required, sis fruit development proceeded, to obtain a similar increase in fruit size. This declining response to thinning was accompanied by a progressively smaller increase in the cell numbers of fruits as the treatments were delayed. Thinning also caused an increase in cell-enlargement rate but the magnitude of the response varied between different experiments and did not appear to be related to the developmental stage at which the treatment was applied.

The larger fruits from thinned trees were more susceptible to bitter pit, breakdown, and rotting caused by Gloeosporium perennans, but were less susceptible to low-temperature injury than fruits from unthinned trees. Bitter-pit incidence was related to fruit size within each treatment and was more severe in fruit where the ratio between the potassium and calcium concentrations was high. Low-temperature injury was associated with fruit with low dry matter and potassium contents. Susceptibility to this disorder and to rotting was also influenced by fruit maturity as measured by the progress of the climacteric rise in respiration rate. There were no marked relationships between storage disorders and the numbers or size of cells in fruits produced by the various treatments included in these experiments.     

The Effects of Nitrogen,Potassium and Sub-Irrigation on the Yield,Quality and Composition of Single-Truss Tomatoes

The effects of nitrogen and potassium on the growth of single-truss tomatoes and on the yield and quality of the fruit have been examined. Two successive crops of cv. Minicraigella were grown with sub-irrigation in a tiered-trough system, the troughs containing a 7:3:2 mixture of loam, peat and grit. Four concentrations of nitrogen in solution (100, 150, 200 and 250 ppm N) were tested in factorial combination with three concentrations of potassium (200, 300 and 400 ppm K), the treatments being replicated four times.

Plant height and leaf length increased markedly with N concentration, as also did the numbers of flowers and marketable fruits per plant, the mean weight per fruit and the total yield. Low N levels delayed harvesting. The proportion of unevenly ripened fruit decreased with increasing concentrations both of N and K. The percentage of hollow fruits was decreased by high K but increased with N concentration.

The titratable acidity of the expressed fruit juices increased significantly with N concentration (P<0.001) but was little affected by K treatment. The N concentration of the nutrient solution also largely controlled the percentage of K in the leaves and the total uptake of this nutrient. These unexpected results were attributed to stimulation of growth by N, leading to increased water requirement and hence to increased application of both N and K by the automatic sub-irrigation system.

The highest yields and best quality fruit were obtained with 250 ppm N and 400 ppm K in the solution, although lower concentrations of K might be preferable after continued cropping in the same compost.     

Comparative studies on the postharvest physiology of fruit from different species of Annona (custard apple)

Summary

Fruit of three Annona species, viz. cherimoya (A. cherimola Mill), sugar apple (A. squamosa L.) and custard apple (atemoya, Annona X) were ripened in ethylene-free air and under propylene. Differences were found in patterns of respiration, ethylene production and fruit firmness changes during ripening. Cherimoya and custard apple fruits showed two successive rises in respiration rate whereas sugar apple fruits showed only one. Ethylene production showed one main peak but the onset of rapid ethylene production occurred after the beginning of the respiration climacteric in all three species. Custard apple fruit had acceptable eating quality (as judged by sensory assessments and chemical analyses of pulp) for up to four days after first detectable softening, when ripened at 20°C in ethylene-free air or under propylene. Fruit ripened in ethylene-free air had better ripe fruit quality than fruit ripened under propylene.     

Einfluss von Biostimulanzien und Lichtreflexionsfolie auf die Fruchtqualität und Farbentwicklung bei Apfel

The aim of this research was to improve inner and external fruit quality and fruit colouration using four-year-old apple ‘Braeburn, Hillwell’ trees on M9 (3?m × 1?m spacing) by employing reflective ground covers and biostimulants at Klein-Altendorf, nr. Bonn, Germany (50°N). Two reflective ground covers were spread on both sides of tree rows seven weeks before anticipated harvest and two biostimulants were applied two times – four and two weeks before harvest. Adjacent trees of the same row without reflective ground cover or without biostimulants served as control.Reflective ground covers significantly improved red colouration from 71°hue in the control to 49°hue with the ground cover Lumilys® and to 40°hue with Extenday®. The red colouration of the lower surface of fruits improved from 85°hue in the control to 52°hue with Lumilys® and 40°hue by Extenday®. Apple trees with Extenday® and Lumilys® produced 69% and 44% well-coloured fruit (with 75–100% fruit colouration) compared with 16–26% in the control.By contrast, an acceleration of ripening processes was not observed in plots with reflective ground covers compared with the control. There were no differences in sugar contents (°Brix) and fruit firmness (kg/cm²), but starch breakdown in fruit with reflective mulch was significantly delayed compared with the control resulting in retarded maturation.An economic analysis based on material costs and lifespan – excluding the labour costs for spreading and removing the ground covers – showed an economic advantage, if these mulches are used more than once a year.Both biostimulants showed neither effects on inner and external fruit quality nor on fruit colouration. Fruits with Wuxal®ATRiun or Sunred® did not improve the percentage of well-coloured fruits (75%–100% fruit surface with red colouration) compared with the untreated control. Similarly, inner and external fruit quality showed no significant differences in fruit firmness, sugar content and starch degradation. An economic analysis based on chemicals’ costs – excluding the labour costs for applying the biostimulants – resulted in no economic advantage. The chlorophyll – based ‘Index of Absorption Difference’ (IAD; measured non-destructively by the DA-meter) in some cases correlated positively with the Streif (maturation) index based on destructive assessment fruit firmness, sugar content and starch breakdown in an ‘ART system’.     

The Effects of Nitrogen,Phosphorus, Potassium,Magnesium and Lime in Factorial Combination on the Size and Shape of Glasshouse Tomatoes

The effects of nutrition on tomato fruit size and shape are summarized, based on the results of a factorial trial in heated glasshouse borders. The varieties grown were Potentate, J168 and Moneymaker.

The average weight per fruit, calculated from total weights and numbers, was decreased by potassium and magnesium sulphates. Both high nitrogen (760–830 lb. N per acre) and low nitrogen (30–150 lb. N) decreased the weight per fruit as compared with the intermediate nitrogen level (300–380 lb. N). The weight per fruit of varieties J168 and Moneymaker, grown for two seasons, was decreased significantly by high phosphorus in one year and increased by lime in both years.

The uniformly coloured and regularly shaped fruits were graded into four commercial-size categories. Expressed as percentages of the sum of these four grades, the proportion of large fruits showed nutritional responses generally similar to those for average weight per fruit, with opposing trends in the smaller size categories.

The proportion of somewhat irregularly shaped fruit in the uniformly coloured categories, studied for six seasons, was appreciably affected by nutrition. Fruit shape was improved by high potassium and magnesium, and also by nitrogen deficiency. High phosphorus affected the shape adversely. Liming improved the shape of fruit of variety Potentate in three out of four seasons, but the opposite effect was found with J168 and Moneymaker in the final season.

The relation of fruit size and shape to soil salinity is discussed.     

The effects of storage temperature and fruit size on firmness,extractable juice,woolliness and browning in two nectarine cultivars

Fruit firmness, extractable juice, woolliness and browning of the mesocarp tissue in ‘Independence’ and ‘Flavortop’ nectarines stored at —0.5°, 3°, 5° and 7°C for four weeks were determined during ripening at 15°C. The firmness of both ‘Independence’ and ‘Flavortop’ during ripening decreased as storage temperatures increased. The percentage extractable juice after cold storage and during ripening varied considerably between cultivars and between the storage temperatures. The extractable juice of fruit stored at higher temperatures tended to increase during ripening, whereas fruit stored at lower temperatures tended to decrease first before increasing. At storage temperatures of —0.5° and 3°C both cultivars passed through a stage of woolliness during ripening, while less woolliness occurred after storage at 5° and 7°C. In both cultivars the percentage extractable juice during ripening was higher on average at storage temperatures of 5° and 7°C. Severe browning of mesocarp tissue in both cultivars occurred during ripening after storage at 3°C. The effect of fruit size on changes in firmness, development of woolliness and mesocarp browning in ‘Flavortop’ nectarines stored at — 0.5°C for four weeks and ripened at 15°C was also determined. Larger nectarines lost firmness more rapidly, woolliness occurred sooner and the mesocarp tissue was more prone to browning than smaller fruit during ripening.     

Maturity of apple cv. Elstar as affected by temperature during a six-week period following bloom

Summary

In two experiments under controlled conditions, the effect of temperature (16, 20 and 24°C, experiment 1; 16 and 22°C, experiment 2) during a six-week period immediately following bloom on the progress of ripening around the normal picking time was evaluated for fruits of cv. Elstar. After six weeks, the temperature in experiment 1 was kept at 20°C throughout. In experiment 2 the temperature was 22°C from week 6 to 14, and 16 or 22°C from week 14 to 22. Post-bloom temperature clearly affected the rate of fruit ripening as reflected in ethylene production, background colour, starch content, firmness and red blush, but these variates did not respond to the same degree. The effect of temperature late in the season on ripening (just during the maturation period) was almost absent when the post-bloom temperature was 16°C. However, when post-bloom temperature was 22°C, fruits were greener, firmer, contained more starch and showed more red blush at 16 than at 24°C given from week 14 to 22. The acid content at ripening was lower at the higher post-bloom temperatures. Irrespective of the post-bloom temperature, acid content was also reduced at the higher temperature given during the maturation period. The content of soluble solids showed no consistent pattern.     

Induction of resistance to Penicillium digitatum and chilling injury in ‘Star Ruby’ grapefruit by a short hot-water rinse and brushing treatment

Summary

Postharvest heat treatments have been used for many years as alternatives to chemical control of fungal diseases and insect infestation of fruits and vegetables. In this study, the effects of a new hot-water brushing (HWB) treatment on the resistance of red grapefruit (C. paradisi cv. Star Ruby) to green mould decay caused by Penicillium digitatum (Pers.: Fr.) Sacc. and on the development of chilling injury (CI) symptoms during cold storage were examined. The HWB treatment comprises rinsing hot water on the fruits as they move along a belt of brush rollers. A twenty second HWB treatment at 59 or 62° reduced decay, after arti®cial inoculation of wounded fruit, by 52 or 70%, respectively, compared with control unwashed fruit, whereas rinsing and brushing the fruit with tap water (~20°) or with hot water at 53 or 56°, were ineffective. HWB treatments applied 1–3 d prior to inoculation were most effective in enhancing the disease resistance of fruit, but were much less effective when the fruit were inoculated on the same day or 7.d later. HWB treatments at 59 or 62° for 20.s also significantly reduced the CI index and the percentage of fruit displaying CI symptoms by 42 and 58%, respectively, after six weeks’ storage at 2° and an additional week at 20°. Furthermore, HWB treatments cleaned the fruit and improved its general appearance without causing any surface damage, and did not influence fruit weight loss, percentage of total soluble solids (TSS) in the juice, juice acidity or fruit colour.     

Effect of temperature on seed and fruit development in three mango (Mangifera indica L.) cultivars

The effect of diurnal maximum/minimum (20/10 or 25/15 °C) temperatures on seed and fruit development of ‘Irwin’, ‘Kensington’ and ‘Nam Dok Mai’ mangoes (Mangifera indica L.) was studied in a controlled-environment glasshouse. Exposure to low temperatures (20/10 °C day/night) 3 days after hand pollination significantly increased the percentage of stenospermocarpic fruit (nubbins), in which embryos were aborted at some stage during early fruit development. There were significant differences between cultivars in the percentage of nubbins produced out of the total fruit set following overnight exposure to 10 °C with 21% for ‘Nam Dok Mai’, 11% for ‘Kensington’ and 3% for ‘Irwin’. At 45 days after pollination, nubbin fruits were much smaller in size and weighed ca. 50% less than normal fruits. The lower percentage of nubbin fruits in ‘Irwin’ implies a greater adaptation to cool temperatures by this cultivar during fruit set and early embryo development.     

Amount of Cortical and Epidermal Tissue Shed From Roots of Apple

Rates of CO₂ production by cv Idared apples were progressively reduced by lowering O₂ levels from 21% to 2% and 1%. Although lowering the temperature from 4° to 2°C also reduced the respiration rate, fruits stored in 1% and 2% O₂ were respiring faster after 100 days at 0°C than at 2° or 4°C. After 192 days the air-stored fruit also showed an increase in respiration rate at 0°C. These higher respiration rates preceded the development of low temperature breakdown in fruit stored in air, 2% and 1% O₂ at 0°C and in 1% 0₂ at 2°C. Progressively lower O₂ concentrations reduced ethylene production whilst increasing the retention of acid (expressed as malic), soluble solids, chlorophyll and firmness. In the absence of low temperature breakdown the effects of reduced temperature on fruit ripening were similar to those of lowered O₂ concentrations. The quality of apples stored at 4°C in 1% O₂ was markedly better than in 2%; the fruits were also free of core flush (brown core) and other physiological disorders.     

Effect of low-pressure storage on the quality of green capsicums (Capsicum annum L.)

Green capsicums (Capsicum annum L.) were stored under low pressure (4 kPa) at 10°C for 5 and 11 days with 100% RH. The results showed that the incidence of stem decay under low-pressure storage for 5 and 11 days and storage at ambient atmosphere at 20°C for 3 days was lower compared to fruits that were stored at regular atmosphere at 10°C. Fruit that had been stored at low pressure at 10°C had no symptoms of flesh rots for up to 11 days, whilst fruit which had been stored at regular atmosphere at 10°C had 6% flesh rots after 11 days storage at 10°C.There was no difference in flesh firmness and colour retention between fruits stored at low pressure and regular pressure at 10°C. Capsicums stored at low pressure had higher overall acceptability compared to fruit that were stored at regular atmosphere at 10°C. These results demonstrate the potential of low pressure storage as an effective technique to manage capsicum fruit quality, however, there was no additional benefit when fruits were stored at low pressure for more than 5 days.     

Postharvest UV-C treatment combined with 1-methylcyclopropene (1-MCP), followed by storage in continuous low-level ethylene atmosphere,improves the quality of tomatoes

Mature green tomatoes (Solanum lycopersicum L. cv Neang Pich) were exposed to 13.6 kJ m^?2 UV-C or 0.5 μL L^?1 1-MCP or combination of 13.6 kJ m^?2 UV-C and 0.5 μL L^?1 1-MCP, with appropriate untreated controls. After treatment, tomatoes were stored in air containing 0.1 μL L^?1 ethylene at 20°C and 100% RH. The untreated fruit ripened significantly faster than those of all other treatments. UV-C treatment alone was able to delay fruit ripening by up to 5 days longer compared to untreated fruits whilst the additional of 1-MCP further delayed fruit ripening. UV-C and 1-MCP treatments alone or in combination had significantly slower ethylene production rates throughout the storage period. The fruit treated with the combination of 1-MCP and UV-C was significantly firmer and had higher total phenolic content compared to that of the other treatments. However, there was no difference between treatments in soluble solids content/titratable acids ratio, chlorophyll content, lycopene content and total antioxidant activity. These results show that UV-C and 1-MCP treatment delay ripening and improve the quality of tomatoes in the presence of low-level ethylene during storage. This new treatment could be used to extend the shelf-life of mature green tomatoes through the supply chain without the use of refrigeration.     

Effect of ethrel in aqueous solution and ethylene released from ethrel on mango fruit ripening

Summary

The effect of ethrel in aqueous solution and ethylene released from ethrel was evaluated on fruit ripening of ‘Kitchner’, ‘Dr Knight’ and ‘Abu-Samaka’ mango. Ripening was enhanced in all treated fruits of the three cultivars at all concentrations used. The ripening rate progressively increased with increase in concentration. Ethylene released from ethrel was more effective in triggering fruit ripening than dipping fruits in aqueous solution of ethrel. Depending on concentration and cultivar, ripening was 1–3.d faster in fruits dipped in 500 and 1000 ppm ethrel and 1–5.d earlier in fruits treated with 250, 500 and 1000 ppm ethylene released from ethrel, compared with untreated fruits. The effect on fruit ripening was indicated by enhanced climacteric peak, increased skin colour, increased total soluble solids and decreased flesh firmness.