Reaction of 25 Apomictic Apple Rootstock Selections to Inoculation with Mixtures of ’latent’ Viruses

Malus sieboldii, M. sargenti and most hybrids showed sensitivity to inoculation with mixtures of ‘latent’ viruses from apple cultivars. The main symptoms were chlorotic leaf spots and leaf distortions combined with severe stunting in many seedlings. There was no reaction in the M. hupehensis group and Bittenfelder Seedling except for stem pitting or stem grooving symptoms in two hybrids. It is suggested that the same sensitivity reaction to apple ’latent’ viruses which leads to incompatibility when apple rootstocks are budded may also cause virus symptoms in apomictic species rootstocks. This would seem to apply especially to the M. sieboldii and M. sargenti groups, but probably not to the M. hupehensis group.     

Storability of ‘Conference’ Pear Under Various Controlled Atmospheres

In two consecutive experimental seasons it was investigated the storage capacity of ‘Conference’ pear (Pyrus communis, L.) under regular air (RA) and various controlled atmosphere (CA) conditions during six months at 0?°C (±0.3). The occurrence flesh browning (FB), core browning (CB) and cavity formation (CF) was evaluated at each 2?months storage intervals and the ripening quality traits analyzed immediately at the end of storage period and after 7 days of shelf-life in air at 20?°C. The storage conditions were: RA; 0.5?kPa O₂?+?0.5?kPa CO₂; 1.5?kPa O₂?+?1.5?kPa CO₂, 2.0?kPa O₂?+?1.0?kPa CO₂; 3.0?kPa O₂?+?6.0?kPa CO₂ and 0.5?kPa O₂?+?6.0?kPa CO₂. After six months, ‘Conference’ pear was very susceptible to FB, CB and CF under CA-storage. The damages started to develop at the second month of storage, increasing continuously until end of storage period. At storage end, pear fruits kept under 0.5?kPa O₂?+?6.0?kPa CO₂ showed a dramatic high occurrence of FB, CB and CF with a severity index of 50.6, 45.3 and 27.1, respectively. The lowest incidences of FB, CB and CF were scored in fruits kept at 2.0?kPa O₂?+?1.0?kPa CO₂ with severity indexes of 1.1, 1.1 and 1.0, respectively. Flesh firmness, skin color, titratable acidity and total soluble solids were satisfactory under 2.0?kPa O₂?+?1.0?kPa CO₂. In conclusion, ‘Conference’ pear cannot be stored under O₂ partial pressure lower than 2.0?kPa and CO₂ higher than 0.5?kPa.     

Rootstock influence on the incidence of rind breakdown in ‘Navelate’ sweet orange

Summary

The influence of three rootstocks, Carrizo citrange (Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf.), Cleopatra mandarin (Citrus reshni Hort. ex Tanaka) and sour orange (Citrus aurantium L.) on the incidence and severity of rind breakdown in ‘Navelate’ sweet oranges was studied over seven years in four orchards. The proportion of affected fruit was greater in trees on Carrizo citrange (60% on an average) followed by Cleopatra mandarin (38%) and then on sour orange (9%). There were also significant differences in the severity of the disorder among rootstocks; more than 35% and 20% of fruit from trees on Carrizo citrange and Cleopatra mandarin, respectively, were rejected for commercialization, whereas only 4% of fruit on sour orange was rejected. Cryo-scanning electron microscopy (SEM) of fruit peduncles showed that average diameter of xylem vessel elements of peduncles of fruits on Carrizo citrange rootstock were 6% and 17% larger than those on Cleopatra mandarin and sour orange, respectively. Defoliation of fruit-bearing branches reduced water loss from fruit, maintained fruit peel water potential at a higher value than that of fruit on undefoliated branches and reduced the proportion and severity of affected fruit. It is concluded that fruit-tree water relationships are related to rind breakdown in ‘Navelate’ oranges and low fruit water content might be responsible for the disorder.     

Rootstock Induced Seasonal Changes of N,P and K Nutrient Levels in Satsuma Mandarin cvs. ‘Okitsu’, ‘Clausellina’ and ‘Silverhill’

Rootstocks-scion relations have critical consequences about nutritional status, tree vigour, resistance to pest and pathogens, yield and yield quality. In this study, we therefore investigated seasonal variations of leaf mineral nutrient concentrations in Satsuma mandarin’s cvs. ‘Okitsu’, ‘Clausellina’ and ‘Silverhill’ budded on different citrus rootstocks under Dörtyol-Hatay, Turkey ecological conditions. Nitrogen (N), phosphorus (P) and K (potassium) concentrations of the leaves showed slightly similar trend each other, in general these nutrients reduced from January to March–April, and increased during the growing season until mid- and late summer, then decreased until December. Despite rootstocks did not significantly affect the leaf N, P and K concentrations rootstock-scion relation was pre-eminent and nutrient dependent. Most conspicuous scion dependent changes were recorded for K concentration whereas P concentration was little influenced. In terms of scion-rootstock combination, the range of N and K concentrations were 2.11% (‘Okitsu’/sour orange) to 2.34% (Silverhill/sour orange), and 1.09% (‘Okitsu’/Carrizo citrange) to 1.39% (‘Clausellina’/Carrizo citrange), respectively; but P concentrations were highly similar %0.13 (‘Okitsu’/sour orange) – %0.16 (‘Clausellina’/Carrizo citrange), in the entire growing season. It can be concluded that there are considerable differences in nutrient uptake ability of scion-rootstock combination.     

Response of ‘Early Imperial’ Mandarins to Selective Harvesting

All cv Early Imperial mandarin fruits with circumferences 14 cm or more were removed in the first week of May or in July and the remaining fruits as well as those from the controls were picked in the last week of August. Increases in fruit circumference and in fruit weight were recorded only on the trees selectively picked in May, suggesting a minimum time requirement for sizing after removing about 25% to 40% of the fruit. Changes in palatability, colour, puffiness and dryness with time indicated that selective harvesting should not be practised beyond late August to avoid dryness and puffiness.     

Preliminary trials to examine the effects of ethephon as a thinner of ‘Gala’ and ‘Jonagold’ apples

Trials in southern Tasmania examined the thinning effects of ethephon on ‘Gala’ and ‘Jonagold’ apples. Untreated controls were compared with ethephon thinning sprays applied at full bloom at 50,100,200,400,800 and 1 600 mg I“1 to both cultivars. Thinning of both cultivars was related to the concentration of the spray and in most cases logistic models were fitted. Thinning effectiveness was largely reflected in increased fruit weight and size. The ‘Gala’ fruit was still not large enough for Australian markets. Ethephon at 200 mg I“1 effectively thinned ‘Jonagold’ and produced the required increases in fruit size and weight. ‘Jonagold’ was overthinned by the high concentrations of ethephon, but this was not reflected in increased fruit weight and size. Ethephon also reduced vegetative growth at the higher concentrations which was considered an advantage. More work is required to establish specific recommendations for either cultivar.     

Cluster Management to Improve Berry Quality in Young ‘Alborz’ Table Grape in the Intermountain West Region,USA

Cluster management in table grapes is an essential cultural practice for production of high quality table grapes. This issue has not been studied in the Intermountain West region in the United States. Thus, the objective of this project was to study the effects of cluster removal, cluster shortening, and vine girdling on yield and quality attributes of ‘Alborz’ table grape during 2012–14 growing seasons. Vines that did not receive cluster removal and cluster cutting (NoClRemNoClCut) tended to have a higher yield but smaller berry weight than those with other cluster managements every year. Vines receiving cluster removal, cluster shortening, and a trunk girdling (ClRemShort&Gird) regime tended to have larger berries and cluster weight than those with other treatments. However, girdled vines were more susceptible to cold damage. Vines receiving cluster removal and cluster shortening had slightly larger berries, better appearance, and marketability than those without cluster removal and without cluster shortening.     

The Effects of Some Summer Pruning and Humic Substance Applications on The Nutritional Value of ‘Alphonse Lavallée’ Grape Cultivar

Viticulture is an important agricultural branch in Turkey. Grape is the most grown fruit species in Turkey. The study was conducted with ‘Alphonse Lavallée’ grape variety (Vitis vinifera L.) grown on grafted 1103 Paulsen rootstock in Turkey in 2016. In the study effects of Control (C), 1/3 Cluster Tip Reduction (1/3 CTR), Shoot Tip Reduction (STR), Humic Substance Application (HS), 1/3 CTR?+?STR, 1/3 CTR?+?HS, STR?+?HS, 1/3 CTR?+?STR?+?HS applications on nutritive values were investigated. According to results; the maximum dry matter content 87.64?g/100?g with HS, 87.76?g/100?g with 1/3 CTR?+?HS, 87.78 with STR?+?HS and 87.67 with 1/3 CTR?+?STR?+?HS applications; the maximum crude protein 3.38?g/100?g with HS and 3.40?g/100?g with STR?+?HS applications; the maximum crude cellulose 4.46?g/100?g with HS application; the maximum total sugar content 64.64?g/100?g with STR and 64.64?g/100?g with HS applications were obtained. No statistically significant difference was found in terms of crude ash content.     

Response of ‘Comice’ pear trees to a postharvest urea spray

A single postharvest urea spray at 5 and 10% increased nitrogen (N) content in one year old bark and wood and in the flower buds and blossoms in 1987. In 1988, there was also an increase in N in one year old bark and wood but not in the N content of flower buds and blossoms. Fruit set was not significantly increased in either year. Control trees were much taller in N in 1988 than they were in 1987 since additional soil N was applied. Urea labelled with 15N was applied to branches and individual spurs immediately after harvest. When the l5N-urea was applied to branches, the next season’s flower buds had 12% of their N derived from the fertilizer (NFF), but when urea was applied to individual spurs only 8% NFF was detected. Remobilization of labelled N from treated to adjacent spurs resulted in less NFF than would occur if all spurs on the same branch received labelled N. Flower clusters distal and basal to the spurs treated with labelled l5N showed considerable amounts (>60% of sprayed spur) of N from the labelled spray. However, harvest analysis of adjacent and distant spur leaves and fruits from treated spurs and branches revealed that urea was only locally mobilized in the tree. Nitrogen status can be altered with postharvest urea sprays but the response varies with the N status of the tree. Postharvest soil application of labelled N showed N movement into blossoms but not in the flower buds.     

Artificial Ripening of ‘Shiraz’ Persimmon (Diospyros kaki Thunb. cv. ‘Shiraz’) Prior to Marketing

Abstract

Although it is one of the traditional fruits, persimmon production in Iran is only about 7,320 tons annually and there has been a decrease in cultivated acreage. The decrease in persimmon consumption can be attributed to the unpleasant astringency of the local Iranian cultivars. The producers' and handlers' lack of knowledge of techniques for removing astringency before sending the fruit to market has greatly influenced this issue. This study was conducted in order to develop recommendations for a simple and economical method for removing the fruit astringency of local cultivars. Fruits of a commercial cultivar (cv. ‘Shiraz’) in Fars province, Iran were harvested at the local commercial maturity stage (breaker stage). The fruits were dipped in ethanol (20, 35 and 50%), acetic acid (3, 6 and 10%), commercial vinegar, hot water (60°C) and tap water as control for 30 min. Some qualitative characteristics such as total soluble solids (TSS), vitamin C, total acids, pH and tannic acid of the treated fruits besides fresh weight changes were measured at 4-day intervals after storage at room temperature. Results indicate that vitamin C and TSS were highest in the 20% ethanol, hot water and 35% ethanol treatments. Total acid was highest in 10 and 6% acetic acid treatments. Tannins were highest in the control treatment and lowest in the 20% ethanol, hot water followed by 35% ethanol. Fruit juice pH was also highest in the 20 and 35% ethanol and hot water. Although tannic acid and total acid declined after treatment, fruit juice pH and TSS increased. Weight loss was lowest in the ethanol 20, 35 and 50%, and hot water treatments, respectively. Results suggest the use of 20% ethanol treatment with ‘Shiraz’ persimmon before short storage and supply to markets would be beneficial in improving consumer acceptance besides being commercially economical and practical.     

Response of secondary bloom of ‘Bartlett’ pear (Pyrus communis L.) to pruning

Summary

Type V secondary bloom of pear (Pyrus communis L.) is associated with pruning and is frequently infected by fire blight (Southwick et al., 2000). The goal of this research was to determine which pruning practices would most likely be associated with subsequent Type V secondary bloom. Pruning date, shoot age, type of pruning cut and shoot orientation were varied and effect on Type V secondary bloom assessed. In both 1998 and 1999, dormant pruning was more likely to result in Type Vs than summer pruning or pruning one month after harvest. Pruning one week after harvest in 1998 was as likely to lead to Type Vs as dormant pruning, but was less likely in 1999. The likelihood that Type Vs would occur was lowest from 49 to 89.d from full bloom (DFB) and at 175 DFB in 1998. The lowest likelihood of Type Vs in 1999 was found on shoots pruned at 83 or 185 DFB. The likelihood for Type Vs rose with increasing shoot age from one to four years, but there was no difference between three- and four-year old shoots. In 1998, stub cuts (severe heading) were more likely to have Type Vs than head cuts when pruning two year old shoots, but not for one year old shoots. In 1999, type of pruning cut had an inconsistent effect on the likelihood for Type Vs and was not the same for each shoot age. NAA applied to summer pruned shoots completely prevented Type Vs from occurring and almost completely stopped Type Vs when applied to dormant pruning cuts. Summer pruning from 50 to 90 DFB or pruning one month after harvest and the application of NAA to pruning wounds may be strategies for reducing the occurrence of Type V secondary bloom.     

Response of the phenylpropanoid pathway to Venturia inaequalis infection in maturing fruit of ‘Braeburn’ apple

Summary

This study investigated the activities of key enzymes in the phenylpropanoid pathway and the accumulation of phenolic products in apple peel in response to infection with Venturia inaequalis [(Cooke) G. Wint.]. We compared healthy apple peel with apple peel showing symptomatic scab lesions, and with peel tissue from 1 – 2 mm around the scab lesions in fruit 1 month before maturity [140 d after full bloom (DAFB)] and at physiological maturity (175 DAFB). Infection with V. inaequalis enhanced the synthesis of some phenolic compounds. Compared to healthy peel, scab lesion tissue had ≤ 3.1-times higher hydroxycinnamic acid content, ≤ 1.3-times higher dihydrochalcone content, and ≤ 3.9-times higher flavan-3-ol content. Scab lesions showed slightly higher phenylalanine ammonia-lyase, chalcone synthase, chalcone isomerase, flavonol synthase, and dihydroflavonol 4-reductase activities. The total amount of phenolics remained relatively stable between the two sampling dates, except for epicatechin and caffeic acid which decreased in amount toward fruit maturity, and levels of catechin which increased in more mature fruit. During fruit maturation, only chalcone synthase and chalcone isomerase activities decreased in all tissues examined. This study showed that the phenylpropanoid pathway in apple fruit peel changed significantly following infection with the apple scab pathogen.     

Harvest parameters to improve the storability of high quality ‘Reinette du Canada’ apple

Summary

‘Reinette du Canada’ apple (Malus domestica Borkh.), which has been declared a Protected Designation of Origin (PDO) product throughout the European Community, is severely affected by bitter pit during storage, but increasing demand for organic produce requires chemical post-harvest treatments to be replaced with organic practices. The objective of this work was to determine the optimum stage of fruit maturity to improve the storability of high quality ‘Reinette du Canada’ apple during storage without applying post-harvest treatments. Seasonal conditions influenced fruit quality and the occurrence of storage disorders in ‘Reinette du Canada’. Harvest maturity also influenced the quality of ‘Reinette du Canada’ apple during storage, with later harvests reducing the development of bitter pit and increasing the soluble solids content:titratable acidity (SSC:TA) ratio. This study suggests that the SSC:TA ratio was a useful parameter for determining the optimum harvest maturity for high acidity, ‘Reinette du Canada’ apple. High quality fruit were obtained after long-term storage when the SSC:TA ratio exceeded 11.0, and fruit firmness at harvest exceeded 90 N. If these thresholds were not achieved, the quality of harvested ‘Reinette du Canada’ apples may not be sufficient to market fruit with the PDO designation. The results of our study also suggested that skin hue angle (hº) measurements may provide a quick and useful index that could replace fruit firmness measurements in the future.     

The Use of Thermotherapy and in vitro Meristem Culture to Produce Virus-Free ‘Chancellor’ Grapevines

ABSTRACT

Grapevines (Vitisspp.) are very susceptible to virus diseases. Virus infection reduces fruit yield and quality. The objective of this work was to determine the usefulness of thermotherapy (37.2°C) and in vitromeristem culture to obtain virus-free grapevine plants cv. ‘Chancellor’. Grapevine leafroll-associated virus 1,3(GLRaV-1, 3) infected grapevines were multiplied in vitrofrom two infected mother-plants in half strength Murashige and Skoog medium (1/2MS) supplemented with 0.5 mg/L of BA and the in vitroplants were initially tested by ELISA to confirm their virus status; subsequently, 96 infected in vitroplants were propagated on 1/2MS medium with BA and subjected to 0, 7, 10, 12, 14, 16, 18, 20 or 22 days of exposure at 37.2°C. Afterward, the apical meristems from the plants surviving the thermotherapy treatment were excised and transferred to fresh 1/2MS medium with 0.5 mg/L of BA and grown in a culture room until they developed into entire plants. Control plants and all the plants that survived thermotherapy were assessed for their virus status using both ELISA and RT-PCR. After 20 days of exposure at 37.2°C, 100% of the plants submitted to thermotherapy were found to be virus-free by RT-PCR and ELISA tests. Plants derived from meristems with two or three primordial leaves remained virus infected. However, when meristem culture was combined with thermotherapy (12 or more days of heat treatment), all the meristem-derived plants were virus-free.     

Flower Bud Cold Hardiness of ‘Muskoka’ Red Raspberry as Related to Water Content in Late Winter

Abstract

‘Muskoka’ red raspberry (Rubus idaeus L.) canes were sampled from a field (latitude 60°10′N) at 2- to 3-week intervals from February to April to examine whether the loss of cold hardening capacity in late winter is connected to the increase in bud water content, or to the increased ability of buds to absorb water. Bud base vascular tissue lost its hardening capacity earlier than floral primordia and was injured at warmer temperatures. Cold hardiness was more closely correlated with bud water content than with water potential. Both low water content and low water potential indicated the ability of tissue to harden at low temperatures. All determined parameters except hardening capacity were positively correlated with mean air temperature during a 2-day period preceding sampling. Loss of bud base vascular tissue hardening capacity coincided with increases in bud water content, maximal water content and water potential in the beginning of April, after diurnal mean temperature had risen above 0°C.     

Hormone and antioxidant responses of Lilium Oriental hybrids ‘Sorbonne’ bulblets to humic acid treatments in vitro

The lily cultivar introduction is a very long process and bulblet development a limiting element in the entire cycle. The aim of the present study was to acquire a highly synchronized model system to gain insight into the bulbing process. Subsequently, this system was implemented to quantify the efficacy of humic acid applications to evaluate the hypothesized positive effect on bulblet growth. Based on weight, bulblet production was promoted with low humic acid concentration treatment (0.2 mg/L, LHA), showing 0.47 g weight and 11.68 mm diameter, while inhibitory effects were observed with increased doses. LHA significantly decreased the gibberellic acid content, and a pronounced phytohormone balance (promotive/inhibitive) was observed, which might be beneficial for the translocation of assimilates from the shoot to sink organs (bulblets). Intriguingly, LHA increased superoxide dismutase, peroxidase, ascorbate peroxidase, catalase, and glutathione reductase activities compared with the control during the early development stages, implicating a possible role for elimination of reactive oxygen species, thereby favouring cell expansion. In conclusion, we initially reported the effects of HA on the development of bulbous plants, showing that a relatively low dose markedly increased the bulblets size via positive GA and antioxidant responses. However, the mechanism of action needs further evaluation.     

Control of superficial scald in ‘Granny Smith’ apples by ultra-low and stress levels of oxygen as an alternative to diphenylamine

Summary

‘Granny Smith’ apples were harvested at weekly intervals, commencing approximately 155 d after full bloom (DFFB), over two successive seasons. Subsamples of the fruit were stored for periods of five and six months, without the application of diphenylamine, under regular atmosphere (RA) (1990/91 season only), and ultra-low oxygen (ULO) controlled atmosphere (CA) conditions. Further samples were subjected to initial low oxygen stress (ILOS) conditions before ULO CA storage. During the 1989/90 season, scald development after five months’ storage was low for fruit which had been picked in the pre- and post-maturity phases, but high on fruit picked at optimum maturity (170 DFFB). Although storage regime had little effect on scald development after five months’ storage, the ILOS + ULO CA treatment resulted in lower levels of scald on the post-mature fruit after six months of storage than was the case under ULO CA storage alone. There was more scald in the 1990/91 season than in the previous season. Under RA storage conditions, scald levels were high after both five and six months of storage, and decreased only slightly the later the apples were picked. Relative to RA, storage under ULC CA conditions led to markedly lower scald levels on the post-mature fruit, but did not greatly reduce scald on the pre-mature and mature fruit. Storage under the ILOS + ULO CA regime, however, conferred low levels of superficial scald on pre-mature, mature and post-mature fruit after both five and six months of storage. These results suggest that although superficial scald on ‘Granny Smith’ apples can be inhibited by a combination of ILOS and ULO CA storage, the development of scald is also affected by factors other than maturity and storage period.     

The Response of Soilless Grown ‘Michele Palieri’ (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.) Grapevine Cultivar to Deficit Irrigation Under the Effects of Different Rootstocks

Global warming, altering the physiology and irrigation demand of grapevines, has already been perceived in certain premium viticulture regions across the world. Selection of proper rootstocks for especially new cultivars has vital role for a sustainable viticulture under water-deficit conditions. The grapevine cultivar ‘Michele Palieri’ has been finding a good reception on the global markets. The objective of this study was to determine the response of ‘Michele Palieri’ cultivar to deficit irrigation using different rootstocks with distinct genetic origins. Two irrigation regimes (Full Irrigation [FI] and Deficit Irrigation [DI]) were applied to the vines of different grafting combinations of ‘Michele Palieri’ with Kober 5 BB, Richter 99, Richter 110, 140 Ruggeri, 44–53 Malégue or grown on own roots. Two years old vines were cultivated in 60?L pots containing sterile peat under controlled glasshouse conditions. Irrigations were regulated according to soil water matric potential (Ψm) levels using tensiometers. The volume of the irrigation water that has to be applied to attain 100% field capacity was performed as FI, while 50% of FI was considered as DI. The water was transported directly into the pots by micro-irrigation systems consisting of individual spaghetti tubes. The vines of DI treatment showed visible symptoms of mild water stress (e.?g., loss of turgor in shoot tips), but no defoliation or leaf necrosis occurred. DI treatment reduced the gs of ‘Michele Palieri’ scion cultivar in varying levels depending on the rootstock. DI treatment also affected vegetative growth of the scion cultivar in different levels. For example, the greatest decrease (26.7%) in shoot length resulting from DI was determined in ‘Michele Palieri’/5 BB grapevines, followed by own rooted vines (13.1%), while the lowest change (2.4%) was found in vines grafted on 110?R. Overall findings of this study imply that the rootstocks originating from V. berlandiery?×?V. rupestris hybrids (110?R, 99?R, 140?Ru and 44–53?M) better performed in a similar genetic aptitude under deficit irrigation regime while the rootstock 5 BB (V. berlandiery?×?V. rupestris) showed more susceptible responses. On the other hand, the general response of own rooted vines were better than those grafted on 5 BB. Therefore, the use of one of V. berlandiery?×?V. rupestris hybrids may be a better choice for viticulture under semiarid regions.     

Seasonal Changes of Shoot Carbohydrates and Growth Characteristics of ‘Trakya İlkeren’ Grape Variety (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.)

This research was conducted to determine the changes in the seasonal carbohydrates of annual shoots and growth characteristics of 10 years old ‘Trakya ?lkeren’ grape variety. Grapevines are grafted on 5BB and 5C rootstocks and they were grown in heavy clay soil conditions. In the study, changes of sugar, starch and total carbohydrates were determined from bud burst to dormancy. While sugar, starch and total carbohydrates showed significant differences (P < 0.01) there were no differences between rootstocks. Although sugar, starch and total carbohydrates of shoots decreased from bud burst to blooming, they increased thereafter until vegetative growth stopped. Total carbohydrates of annual shoots have been found to accumulate in period from blooming to harvest. Total and mean leaf area, shoot length and diameter, total chlorophyll and chlorophyll a/b ratio showed significantly variation among rootstocks and phenological stages (P < 0.01). Whereas the highest chlorophyll contents were found in the blooming, it was found at the lowest through to harvest. Overall mean and total leaf area, shoot length and shoot diameter, total chlorophyll content and chlorophyll a/b ratio were significantly higher on 5BB grafted vines. In the study, 5BB rootstocks are found suitable in terms of shoot carbohydrate accumulation and growth characteristics for ‘Trakya ?lkeren’ grape variety.     

Determination of the optimal pre-storage delayed cooling regime to control disorders and maintain quality in ‘Honeycrisp’TM apples

Summary

Several pre-storage time (0, 1, 2, 4, and 6 d) and temperature (3.5º, 10º, 15º, 20º, 25º, and 30ºC) delayed cooling (DC) treatments were tested on harvested ‘Honeycrisp’^TM apples to determine which combination was optimal for reducing soft scald and low temperature breakdown (LTB), while maintaining the highest fruit quality [i.e., firmness, minimal mass loss, titratable acidity (TA), soluble solids content (SSC), absence of rot, and minimal skin greasiness] after 4 months of refrigerated air (RA) storage. Fruit were harvested from three separate Annapolis Valley (Nova Scotia) orchard sites in 2006 and in 2007. Multiple linear regression and surface response curves showed that fruit firmness and SSC generally increased throughout the DC treatment, but were affected curvilinearly by temperature, reaching a maximum at approx. 15ºC, then declining. Loss of fruit mass was positively related to a (day temperature²) interaction, indicating that it increased synergistically the longer and the warmer the DC treatment. Fruit acidity was affected only by temperature, with the highest TA values at approx. 15ºC, then declining at higher DC temperatures. Multiple logistic regression and surface responses demonstrated that the incidence of soft scald declined curvilinearly the longer and the warmer the DC treatment, while LTB declined curvilinearly with increasing DC temperature only. A positive (day² temperature²) interaction indicated that fruit greasiness increased non-linearly as the duration and temperature of DC increased. Collectively, these results show that both soft scald and LTB were suppressed or eliminated by a DC regime of 25ºC for 1 – 2 d, or 30ºC for 1 d, without incurring a major reduction in fruit quality.