Influence of growth regulators on setting,retention and weight of fruits in two cultivars of litchi

Investigations were undertaken to explore the possibility of improving setting, retention and weight of fruits in ‘Early Seedless’ and ‘Calcuttia’ cultivars of lichi (Litchi chinensis) by means of growth regulators. Indole acetic acid (IAA) at 20, 40 and 80 mg l^?1, 2,4-dichlorophenoxy acetic acid (2,4-D) at 2,4 and 8 mg l^?1 and gibberellic acid (GA₃) at 50, 100 and 150 mg l^?1 were sprayed on panicles in the first fortnight of April, when 50–100% flowers had opened. All 3 growth regulators caused a favourable effect on fruit setting, fruit retention and weight of individual fruits, but IAA at 20 mg l^?1 proved the best for enhancing setting, GA₃ at 50 mg l^?1 for increasing retention and GA₃ at 100 mg l^?1 for improving fruit weight. IAA and GA₃ should, therefore, be used in combination. Between the 2 cultivars tested, ‘Calcuttia’ proved superior to ‘Early Seedless’ in fruit setting, fruit retention and weight of individual fruits.     

Effect of GA3, Planofix (NAA) and Ethrel on granulation and fruit quality in ‘Kaula’ mandarin

The effect of GA₃ 15 mg l^?1, Planofix (NAA = 1-naphthalene acetic acid) 300 mg l^?1 and Ethrel 250 mg l^?1 on granulation and fruit quality in ‘Kaula’ mandarin (Citrus recticulata Blanco) was studied during 1975–1976. Three sprays of Planofix reduced the incidence of granulation to 30.7% from 62.7% in control. Three sprays of GA₃ were almost equally effective (31.3% granulation). These treatments also improved the fruit quality and gave the highest fruit weight, pulp percentage, juice, T.S.S., reducing and non-reducing sugars and ascorbic acid, and the lowest acidity, peel and rag. In both these treatments (3 sprays of GA₃ or Planofix) the T.S.S. was 9.3% (8.1% in control). The application of 3 sprays of Planofix 300 mg l^?1 or GA₃ 15 mg l^?1 is, therefore, considered to be successful in reducing the granulation in this cultivar of mandarin.     

The influence of wax emulsion,morphactin and gibberellic acid on the storage behaviour of indian gooseberry fruits

Qualities of Indian gooseberry fruits (Phyllanthus emblica L.) were determined after dip-treatment with wax emulsion (WE) with or without morphactin (Mor) and gibberellic acid (GA₃). Dip-treatments with 100–500 mg l^?1 Mor reduced marketability by inducing browning and high weight loss, but loss in ascorbic acid was checked and phenols increased. 10 mg l^?1 Mor maintained marketability at par with control, effectively controlled loss in ascorbic acid, and increased acidity and reducing sugars. GA₃, although failing to control the loss of ascorbic acid, was effective in checking browning and thereby increased the market value of fruits as compared with controls and Mor-treated fruits.WE with or without Mor (10 mg l^?1) controlled browning, accumulation of phenols and losses in weight and moisture as compared with 10 mg l^?1 Mor, 100 mg l^?1 GA₃, or control, but could not retain ascorbic acid in comparison to 10 mg l^?1 Mor-treated fruits. Marketability of fruits having had treatment with either WE or GA₃ was the same. Fruits having had combined treatment with WE and 10 mg l^?1 Mor had maximum marketability. Minimum marketability was observed in fruits subjected to a combined treatment of WE + 100 mg l^?1 GA₃ due to maximum infection with Aspergillus spp. and Penicillium spp.     

Parthenocarpic fruit production in loquat (Eriobotrya japonica Lindl.) by using gibberellic acid

This study evaluates the effect of gibberellic acid (GA₃) in inducing parthenocarpy in ‘Algerie’ loquat, as well as the optimum treatment conditions and associated techniques, hand thinning and ringing, to produce seedless fruit with high enough quality for fresh consumption. GA₃ applied in the course of the phenological growth stages 504–508 of the BBCH-scale produced seedless fruits, with the magnitude of the response depending on the concentration applied and number of treatments. Percentage of panicles bearing seedless fruitlets significantly increased with increasing GA₃ concentrations up to 100 mg l⁻¹ and significantly and positively correlated with the number of treatments applied. Trees treated three times with 100 mg l⁻¹ developed more than 90% of panicles bearing almost 7 seedless fruits per panicle, which were smaller in size, drier and slightly acid but similar in TSS concentration and skin colour than seeded fruits from untreated trees. Fruit thinning to 3 fruits per panicle did not increase seedless fruit size, but ringing performed at the onset of cell enlargement stage, growth stage 702 of the BBCH-scale, significantly increased fruit size by 12–15%, depending on the year. Trees treated three times with 100 mg l⁻¹ of GA₃ and ringed produced 26 kg, on average, of seeded fruit of suitable commercial quality.     

Effect of exogenous growth regulators on flowering and cytokinin levels in azaleas

‘Alaska’ and ‘Redwing’ azaleas having dormant flower buds were sprayed with gibberellins (GA₃ or GA_{4 + 7}) alone and in combination with thiourea, N⁶ benzyl adenine (BA) or kinetin weekly for 3 or 4 weeks to test the efficacy of these materials in breaking bud dormancy. Additional plants received 6 weeks of cold storage at 4.5°C or glasshouse day temperatures of 21°C and above. The 2000 and 3000 mg l^?1 GA₃ and Ga_{4 + 7} sprays were better than 1000 mg l^?1 in promoting flowering, with ‘Redwing’ responding better than ‘Alaska’. GA-treated plants flowered in fewer days than those receiving cold storage. Flower diameter and pedicel length increased with higher levels of GA, and flower uniformity was comparable to cold-stored plants on most GA-treated ‘Redwing’-plants. Thiourea, BA and kinetin applied alone had no effect and considerable cytokinin activity was highest in GA-treated buds 14–21 days after treatment application. No increase in activity occurred on plants not receiving GA.     

Responses of day-neutral,June-bearing and everbearing strawberry cultiv ars to gibberellic acid and phthalimide treatments

Field grown day-neutral, June-bearing and everbearing strawberry cultivars responded similarly to GA₃ in most cases. GA₃ stimulated daughter-plant production in ‘Hecker’ (DN) and suppressed it in ‘Guardian’ (June). Fifty mg l^?1 GA₃ increased initial runner production of all cultivars, while both 50 and 100 mg l^?1 GA₃ increased fruit yield the year following treatment. In greenhouse studies, GA₃ initially increased leaf number, petiole length and runner production, but the effects diminished with time. Phthalimide at 1000 mg l^?1 was most effective in increasing leaf number.     

Fruit thinning in ‘Conference’ pear grown under deficit irrigation: Implications for fruit quality at harvest and after cold storage

Fruit thinning in pear is feasible for mitigation of water stress effects. However, it is not well known how fruit quality at harvest and after cold storage is affected by pre-harvest water stress. Even less is known about the effects of fruit thinning on quality under these circumstances. To elucidate these, we applied deficit irrigation (DI) and fruit thinning treatments to ‘Conference’ pear over the growing seasons of 2008 and 2009. At the onset of Stage II (80 and 67 days before harvest in 2008 and 2009, respectively), two irrigation treatments were applied: full irrigation (FI) and DI. FI trees received 100% of crop evapotranspiration (ETc). DI trees received no irrigation during the first three weeks of Stage II to induce water stress, but then received 20% of ETc to ensure tree survival. From bud-break until the onset of Stage II and during post-harvest, FI and DI trees received 100% of ETc. Each irrigation treatment received two thinning levels: no thinning leaving commercial crop load (∼180 fruits tree⁻¹), and hand-thinning at the onset of Stage II leaving a light crop load (∼85 fruits tree⁻¹). Under commercial crop loads, DI trees were moderately water-stressed and this had some positive effects on fruit quality. DI increased fruit firmness (FF), soluble solids concentrations (SSC) and acidity at harvest while no changes were observed in fruit maturity (based on ethylene production). Differences in FF and acidity at harvest between FI and DI fruit were maintained during cold storage. DI also reduced fruit weight loss during storage. But fruit size was reduced under DI. Fruit thinning under DI resulted in better fruit composition with no detrimental effect on fresh-market yield compared to un-thinned fruit. Fruit size at harvest and SSC values after five months of cold storage were higher in fruit from thinned trees than fruit from un-thinned trees. Fruit thinning increased fruit ethylene production, indicating advanced maturity. This may lead to earlier harvest which is desirable in years with impending drought. Fruit thinning is therefore a useful technique to enhance pear marketability under water shortage.     

Gibberellic acid and fruit set in sweet orange

A single GA₃-spray at petal-fall to the entire tree enhanced initial set in the ‘Navelate’ sweet orange (Citrus sinensis L. Osbeck), but this effect was transient and in most cases final yield was not increased. When followed by girdling, final yield was increased even in the most productive orchards, this effect being due to an increase in fruit number while fruit size was unaffected. The response was markedly dependent on the GA₃ concentration, 5 mg l^?1 giving the best results. Higher concentrations up to 20 mg l^?1 even reduced yield compared to the untreated control trees. Chlormequat reduced the number of fruits finally cropped without affecting their size, an effect which may be explained through a reduction in the endogenous gibberellin levels.     

Response of kiwifruit (Actinidia deliciosa cv. Allison) to post-harvest treatment with 1-methylcyclopropene

Summary

Experiments were conducted to observe the effect of different concentrations of 1-methylcyclopropene (1-MCP) on the post-harvest life and quality of ‘Allison’ kiwifruit (Actinidia deliciosa). Fruit were treated with 1-MCP at 0.5 µl l^–1, 1.0 µl l^–1, or 2.0 µl l^–1, un-treated fruit served as controls. Each 1-MCP treatment was applied for 24 h at 20°C. After treatment, fruit were transferred to ambient temperature storage (22º ± 4ºC; 65 – 70% relative humidity) for 18 d, during which time observations on various physical, physiological, and biochemical parameters were recorded at 3 d intervals. Our results indicated that 2.0 µl l^–1 1-MCP was the most effective treatment to delay softening and ripening in ‘Allison’ kiwifruit, as such fruit showed the lowest mean weight loss (9.8 ± 0.2%), the highest mean fruit firmness value (32.7 ± 0.2 N), and began to ripen only after 12 d in storage, whereas untreated fruit started ripening on day-6 of storage. The activities of fruit softening enzymes such as polygalacturonase (PG; 58.5 ± 0.3 µg galacturonic acid g^–1 FW h^–1), and lipoxygenase (LOX; 3.96 ± 1.3 µmoles linoleic acid oxidised min^–1 g^–1 FW h^–1) were lower, and total phenolics (TP) contents (24.3 ± 0.3 mg 100 g^–1) and anti-oxidant (AOX) activities (12.5 ± 0.03 µmol Trolox g^–1 FW h^–1) were higher in 1-MCP-treated fruit than in untreated fruit (PG, 98.3 ± 0.5 µg galacturonic acid g^–1 FW h^–1; LOX, 4.39 ± 1.0 µmoles min^–1 g^–1 FW h^–1; TP, 5.3 ± 0.6 mg 100 g^–1; AOX, 4.7 ± 0.02 µmol Trolox g^–1 FW h^–1, respectively). In addition, 1-MCP-treated fruit exhibited lower rates of respiration (48.3 ± 0.4 ml CO₂ kg^–1 h^–1) and ethylene production (30.2 ± 0.02 µl kg^–1 FW h^–1) than untreated fruit (58.9 ± 0.6 ml CO₂ kg^–1 h^–1; 38.7 ± 0.04 µl kg^–1 FW h^–1, respectively). Similarly, 1-MCP-treated fruit had higher titratable acidity (TA; 1.33 ± 0.3%) and ascorbic acid (AA) contents (115.9 ± 2.6 mg 100 g^–1 pulp) and lower soluble solids contents (SSC; 8.33º ± 0.2º Brix) than untreated kiwifruit (TA, 1.0 ± 0.2 %; AA, 105.3 ± 2.2 mg 100 g^–1 pulp; SSC, 13.7º ± 0.3º Brix, respectively). Thus, 2.0 µl l^–1 1-MCP can be used for the post-harvest treatment of ‘Allison’ kiwifruit to enhance its shelf-life and marketability by approx. 6 d.     

Leatheriness and mealiness of peaches in relation to fruit maturity and storage temperature

Summary

`Huangjin' peaches (Prunus persica Batsch) were harvested at commercial harvest time (commercial) and 20 d before (early) or after (later) commercial harvest. Fruit from each harvest were stored at three temperature regimes (0, 5 and 10°C) at 95% r.h. After four weeks of storage at 0 or 5°C, early harvested fruit developed more leatheriness but less mealiness and later harvested fruit did not develop leatheriness but developed more mealiness comparedwith fruit from commercial harvest. Overall, fruit stored at 5°C developed more mealiness but less leatheriness than fruitat 0°C for the same period of storage. When stored at 10°C for two weeks, after which fruit were senescent, fruit did not develop any leatheriness or mealiness regardless of harvest times. Fruit with leatheriness were firmer (>30 N) thanjuicy or mealy fruit (<10 N) after the same period of cold storage and 4 d at 20°C. Mealy fruit were as soft as juicy fruit. 1-Aminocyclopropane-1-carboxylate oxidase (ACO) activity, 1-aminocyclopropane-1-carboxylic acid (ACC) content, and polygalacturonase (PG) and galactosidase (GAL) activities were lower, and insoluble pectin content was higher in leathery fruit than that in juicy or mealy fruit. ACO, PG and GAL activity, ACC, and insoluble pectin content were similar between mealy and juicy fruit.     

Preharvest aminoethoxyvinylglycine treatments reduce internal browning and prolong the shelf-life of early ripening pears

The effect of aminoethoxyvinylglycine (AVG) on internal browning (IB) and keeping quality of early maturing European pears cv ‘Camusina di Genova’ and ‘Camusina di Bonarcado’ was examined over 10 days of storage at 18 °C. AVG was applied at 125 or 250 mg/L 2 weeks before harvest. At harvest fruit treated with AVG was less ripe than control fruit, being significantly firmer and experiencing lower values of maturity stage (based on ground color), maturity index (calculated value) and IB, depending on the AVG dose and cultivar. During storage, there was no treatment-dependent difference in titratable acidity and total soluble solids of juice, while both treatments reduced ethylene and respiration rates, delayed the ripening process and lowered the incidence of IB and the loss of firmness, especially when applied at 250 mg/L. In addition, AVG treatment significantly reduced decay development in both cultivars, mainly when it was applied at 250 mg/L. This effect was related to the delay of ripen and to possible inhibition of ethylene production by the pathogens and/or infected tissues.     

Effects of nitric oxide fumigation on post-harvest core browning in ‘Yali’ pear (Pyrus bretschneideri Rehd.) during cold storage

Summary

Core browning often occurs as a physiological disorder in ‘Yali’ pear (Pyrus bretschneideri Rehd.) and results in a high losses during storage. In this study, the effects of fumigation with nitric oxide (NO) gas on the incidence of core browning in ‘Yali’ pears during cold storage were investigated. ‘Yali’ pear fruit were treated with 0, 10, 20, or 30 µl l^–1 NO at 25º ± 2ºC for 3 h under anaerobic conditions, then stored at 0º ± 1ºC under normal air for up to 120 d. The data showed that fumigation with 20 µl l^–1 NO was most effective at suppressing core browning. Thereafter, treatment with 20 µl l^–1 NO was used for comparisons with untreated control fruit in experiments to measure changes in total phenolics contents, polyphenol oxidase (PPO) activities, and the contents of glutathione (GSH), ascorbic acid (AsA), and NO in fruit core tissue during storage. The results showed that NO-fumigated fruit had lower PPO activity, but higher GSH and AsA contents in their core tissue compared with untreated control fruit. NO fumigation also maintained higher endogenous NO levels in core tissue after 60 d in storage, while the total phenolics contents of fruit remained at lower levels until day-100 of storage. These results indicate that the inhibitory effect of fumigation with

20 µl l^–1 NO on core browning was associated with its effects on reducing PPO activity and total phenolics contents, while maintaining the contents of GSH and AsA in core tissue of ‘Yali’ pear during cold storage.     

Low temperature and gibberellic acid stimulation of germination in Sambucus caerulea Raf

Sambucus caerulea (elder) seeds did not germinate after 4°C cool treatments for up to 30 days, when monitored for a further 30 days at 21°C. When seeds were soaked for 24 h in gibberellic acid (GA₃) prior to and during cold treatment, germination percentage depended on GA₃ concentration and duration of cold treatment. The highest germination percentage was 55 (1000 mg l⁻¹ GA₃ for 30 days at 4°C). When seeds were treated with ethephon at 0, 100 or 1000 mg l⁻¹, no germination was recorded after a subsequent 30-day 4°C treatment. Ethephon added to GA₃ gave a strong interaction, leading to further promotion in germination. Optimal germination was obtained after 1000 mg l⁻¹ GA₃ and 100 mg l⁻¹ ethephon for 30 days at 4°C (69%).The addition of ethanol, acetone, dimethyl sulfoxide or polyethylene glycol to the GA₃ soak as infusion agents either reduced or did not change the germination percentage.     

Vegetative growth and nutritional status as influenced by auxins and gibberellic acid,and their effect on fruit yield in lemon

Application of 2,4-D and 2,4,5-T at concentrations ranging from 5 to 20 mg l^?1 to 5-year-old ‘Pant Lemon-1’ (Citrus limon Burm) trees reduced the vegetative growth in terms of height, spread, shoot length, number and size of the leaves in the autumn flush. Various NAA treatments (5–20 mg l^?1), however, enhanced growth, but not to the extent that was observed after GA₃ treatments. Application of GA₃ at 10–40 mg l^?1 significantly enhanced all aspects of growth, and the effects were most pronounced at 20 and 40 mg l^?1. Nutritional status of the leaves showed a slight variation in relation to vegetative growth under various treatments.Some 2,4-D- and 2,4,5-T-treatments increased the fruit yield over the control, which could suggest mobilization of foods even at the expense of reduced vegetative growth. On the other hand, NAA, particularly at 10 mg l^?1, increased both vegetative growth and yield, suggesting that the transport of the photosynthates from the leaves to the fruits was not at the expense of new growth extension. Due to excessive growth enhancement under higher concentrations of GA₃ (20 and 40 mg l^?1), comparatively fewer nutrients were translocated to the fruit “sinks”, thereby resulting in a non-significant decrease in yield.     

Improving ‘Bing’ sweet cherry fruit quality with plant growth regulators

Final fruit diameter is the prime determinant of sweet cherry fruit value. Previous research has shown that mesocarp cell size accounts predominantly for variability in final fruit size, within a genotype. Our research program evaluated the potential to improve sweet cherry fruit size/weight with growth regulators to affect cell division and/or cell expansion stages. In the current study we screened 8 plant growth regulators (PGRs), including cytokinins, gibberellins, and auxins, and their combinations for their ability to increase ‘Bing’ fruit weight. Each PGR was mixed in lanolin paste and applied to fruit pedicels at 9 or 30 days after full bloom (DAFB), to coincide with estimated peak in cell division and cell expansion activity, respectively. Several cytokinins applied 30 DAFB improved fruit weight significantly (ca. +15%) with N-(2-Chloro-4-pyridyl)-N′-phenylurea (CPPU) and 6-(3-hydroxybenzylamino) purine (mt-Topolin) at 100 mg l⁻¹ being the most effective. Gibberellins, applied alone, improved fruit size and delayed fruit maturation and exocarp coloration. GA₃ at 200 mg l⁻¹ applied at 9 DAFB was the most effective and improved final fruit weight by 15%. Fifty-six percent of the fruit from this treatment were ≥9 g compared to 15% of similar weight fruit from untreated limbs. Both GA₃ and GA_4/7 treatments applied 9 DAFB increased fruit radial expansion. 4-Chlorophenoxyacetic acid, a synthetic auxin, also stimulated higher fruit growth rates at stage I and stage II, and fruit color development, but did not improve final fruit size.     

Effects of growth regulators on growth and flowering in Hippeastrum hybridum hort

Soaking of bulbs in 3 concentrations of indoleacetic acid (IAA), gibberellic acid (GA₃), 2-chloroethyltrimethyl ammonium chloride (cycocel) or 2-chloroethylphosphonic acid (ethrel) showed various responses on growth and flowering. IAA increased the weight and number of bulblets, GA₃ increased bulb weight. Cycocel (1000 mg l^?1) increased the number of flowers, while GA₃ increased the diameter of the flowers.Application of IAA at 100 mg l^?1 and GA₃ at 10, 100 or 1000 mg l^?1 twice as foliar spray at an interval of 30 days promoted the number of bulblets on the treated plants, while high concentrations of cycocel and ethrel (1000 mg l^?1) increased the weight of bulblets. All concentrations of IAA, GA₃ and 1000 mg l^?1 cycocel increased the number and size of the flowers.     

The role of Pre-harvest Aminoethoxyvinylglycine (AVG) Treatments on Total Phenolics,Antioxidant Capacity and Fruit Quality Attributes of Sweet Cherry Cultivars

The present study was conducted to investigate the effects of pre-harvest aminoethoxyvinylglycine (AVG) treatments on fruit quality parameters and bioactive compounds of sweet cherry fruits (Prunus avium L. cvs. ’0900 Ziraat’, ‘Regina’ and ’Sweetheart’). Whole trees were sprayed once with an aqueous solution containing AVG (0, 100 and 200?mg L^?1) three weeks before the anticipated commercial harvest. Measurements were performed a week before anticipated harvest date, at anticipated harvest date and a week after anticipated harvest date. AVG treatments significantly maintained flesh firmness of all three sweet cherry cultivars. Harvest was delayed at least for a week through the keeping of flesh firmness with AVG treatments. The treatments slowed down the red skin color development in all three cultivars. The measurements performed over fruits collected at different ripening stages revealed that AVG resulted in decreased total phenolics and total anthocyanin and ultimately decreased antioxidant capacity in sweet cherry fruits. AVG treatments also decreased soluble solids content and increased titratable acidity of the fruits. This study revealed that pre-harvest AVG treatments were more effective in delaying sweet cherry fruit softening. The main advantage is to maintain the firmness of late-harvested fruit by retaining fruit quality attributes of sweet cherry fruit.     

GA4+7 plus benzyladenine reduce foliar chlorosis of Lilium longiflorum

The effectiveness of two commercial formulations of gibberellin (GA) and benzyladenine (BA) for reducing foliar chlorosis on Easter lily (Lilium longiflorum Thunb.) was compared. On a per liter basis, plants were sprayed with 0, 100, 200, or 400 mg (BA equivalent) of Accel (GA₄₊₇:BA of 1:10) or Promalin (GA₄₊₇:BA of 1:1) when the crop leaf area index (LAI)=3. One group of plants was sprayed with 100 mg of Accel or Promalin (BA equivalent) per liter twice: once at LAI=3 and again 3 weeks later. Plants were harvested when the largest flower bud on each plant measured 13 cm in length, stored for 0 or 3 weeks at 2.5°C in the dark, and then moved into a post-harvest evaluation room at 21°C, where foliar chlorosis was monitored for 3 weeks. Senescence of some lower leaves on plants in every treatment was evident at harvest, and incidence of senescence increased during the 21 days of post-harvest evaluation. Cold storage increased the number of leaves senescing during the subsequent evaluation period. Application of Promalin or Accel significantly reduced leaf senescence compared to that of untreated plants. At harvest, 21% of the leaves on untreated plants were senescent, while plants treated with Promalin or Accel averaged 3 or 9% senescent leaves, respectively. Following 7 days of post-harvest evaluation, Promalin was more effective in preventing chlorosis than Accel at the 400 mg l⁻¹ (BA equivalent) level. Following 14 or 21 days of post-harvest evaluation, Promalin was more effective than Accel for the 100 mg l⁻¹ 2× and 400 mg l⁻¹ (BA equivalent) treatments.Plants in all Promalin and Accel treatments were taller than untreated plants 1 week after sprays were applied. At harvest, plants sprayed with Promalin were between 6 and 14 cm taller than untreated plants, but those treated with Accel were the same height as untreated plants.Neither Promalin nor Accel influenced the occurrence of malformed or aborted flowers in this study. However, cold storage significantly increased the number of plants with aborted buds and malformed flowers. Unstored plants averaged 0.16 aborted buds and 0.02 malformed flowers each, while those stored 3 weeks averaged 0.51 aborted buds and 0.18 malformed flowers each.     

Effects of 22S, 23S-Homobrassinolide and Gibberellic Acid on Occurrence of Physiological Disorders and Fruit Quality of ‘Summit’ and ‘Regina’ Sweet Cherries

Plant growth regulators play a vital role in fruit growth and development. However, effects of compounds belonging to the group of brassinosteroids have not been fully investigated in sweet cherries. One relatively new and one commonly applied growth regulator, 22S, 23S-Homobrassinolide and GA₃, respectively, were tested on ‘Summit’ and ‘Regina’ sweet cherries to determine the effects on fruit quality and physiological disorders. The substances were applied with a handgun sprayer at full bloom and at the beginning of fruit development (shuck split) for a 2-year period. GA₃ was applied at the concentrations of 25, 50, 100 mgL^?1 and 22S, 23S-Homobrassinolide at 0.05, 0.1, 0.5 mgL^?1. A combined application of 100 mgL^?1 GA₃ + 0.1 mgL^?1 22S, 23S-Homobrassinolide was also applied. Effects of GA₃ and 22S, 23S-Homobrassinolide on fruit weight and size were evident for the concentrations applied and between the seasons for both of the cultivars. Combination of the both growth regulators and 100 mgL^?1 GA₃ alone produced longer fruits compared to the control trees in ‘Regina’. The 22S, 23S-Homobrassinolide applications increased the firmness of the flesh slightly, but not to a great degree, compared to the GA₃ applications alone. The brightness of the red color was better with GA₃ applications in ‘Summit’ and ‘Regina’. Brassinosteroid caused the fruits to have comparably dull red color. Total soluble solid contents of the cultivars were influenced by the substances and the year of the application. Stem resistance to separation from the fruit was under the influence of both treatments and seasons. In general, 22S, 23S-Homobrassinolide provided better stem resistance than the GA₃ applications. There were no effects of the substances on the development of physiological disorders.     

Effects of high-humidity storage on quality,decay and storage life of cherry,lemon and peach fruits

Sweet cherries (Prunus avium (L.) ‘Lambert’ and ‘Blackboy’), lemons (Citrus limon (L.) Burm. f. ‘Lisbon’) and peaches (Prunus persica (L.) Batsch, ‘Summerset’) were stored at 77–83, 90–94 and 95–99% RH (high humidity) at near-optimal storage temperatures after harvest and treatment with fungicides. High-humidity storage did not increase the storage life of peaches held at 0°C, but the life expectancy of cherries (both cultivars) was extended by 7–10 days at 0°C, and of lemons by at least 4 weeks at 10°C when fruit were stored at 95–99% RH compared with levels below 95%. The beneficial effects of high humidity were attributed to retardation of peel desiccation and associated reductions in fruit deformation, peel de-greening, chilling-injury and decay in lemons and to the maintenance of a fresher stalk and a firmer, less shrivelled fruit in cherries. High humidity had no effect on decay in cherries or peaches, but it significantly reduced weight loss and delayed the appearance of shrivel in peaches stored at 0°C. However, after storage at high humidity for 4 weeks, peaches ripened with low rates of C₂H₄ evolution and showed severe low-temperature injury, slight peeling-injury and a poor flavour ex-store.