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• Influence of foliar nutrition on apple production

  15-18.

  F. Stampar

  A. Solar

  M. Hudina

  Views:

  133

  On the basis of different experiments the technology of intensive foliar nutrition was studied in apple orchards in the period from 1996 until 2000. Yearly apple nutrition programs based on soil analyses. The foliar nutrition program was prepared in accordance with the soil, fruit analyses and climatic conditions. If needed, certain improvements were made according to the analyses of leaves and precipitation in the current year. The richness of the soil and ratios between individual nutrients gradually improved. The foliar nutrition influenced the yield quantity, quality and flower bud differentiation. The yield was doubled and the mean of five years reached 70 tons per hectare. In spite of high yields there were no problems with alternative bearing. The analyses of soluble solids, firmness, fructose, glucose, sucrose, malic acid, citric acid in the fruits and mineral soil composition indicated that the produced fruits were of high quality despite greater yields.

• Historical apple cultivars that display high level of resistance to fire blight

  19-23

  K. Kása

  M. G. Tóth

  M. Hevesi

  Views:

  134

  Following the first outbreak of fire blight caused by the bacterium Erwinia amylovora (Burrill) Winslow et al. in Hungary, we have started research with the aim to screen domestic gene sources, mostly historical Hungarian apple cultivars, for disease resistance as part of an apple breeding program for multiple resistance. The present study was conducted with the aim to choose the most tolerant historical apple cultivars among 25 selected cultivars by screening their behavior towards fire blight under controlled conditions. Six cultivars were shown to be the most disease tolerant: `Batul', 'London pepin', Nemes Sóvári Alma', `Sikulai', `Szemes alma', Wilmos renet'. We evaluated these cultivars by investigating both morphological- characteristics under original environmental circumstances and fruit quality. The cultivars had a remarkable degree of fire blight resistance compared to the control cultivars. These were not competitive with the commercially grown 'Jonathan M40' during cultivar tests but on the basis of certain characteristics they could serve as genetic sources for breeding new varieties.

• Healthcare values and potential uses of the new Hungarian apple varieties on the basis on fruit analysis

  25-28.

  G. Ficzek

  M. Ladányi

  Zs. Radeczky

  M. Tóth

  Views:

  199

  Biological active compounds and valuable characteristics of some apple varieties and candidates were measured in our trials. Fruits of ’Rosmerta’, ’Hesztia’, ’Cordelia’ and ’Artemisz’ are recommended to enrich the Hungarian assortments for fresh consumption and choice of new tastes. Based on examined parameters it can be assumed that novel Hungarian resistant varieties are suitable for juice and fruit concentrate production, and due to high pectin content of their remaining pomace these varieties can be raw material of pectin production as well as they are also suitable for jam production mixed with other fruit species. Furthermore, functional food industrial product having high quality can be produced by using novel resistant varieties because of their high pectin and polyphenol content. Beside of their high market value their suitability for growing among orchard conditions is confi rmed by lower costs of production because of less plant protection treatments.

• Ascospore dispersal of Venturia inaequalis and subsequent development of scab symptoms in a Hungarian organic apple orchard

  35-37.

  I. J. Holb

  Rózsa A.

  Abonyi F.

  Views:

  259

  In this study, we aimed to study ascospore dispersal of Venturia inaequalis and subsequent disease development in an organic apple orchard (Eperjeske) in 2012 and 2013 on apple cultiva ’Mutsu). Burkard spore trap in March and April were used to monitior ascospore concentration and number of scab symptoms were assesed 20 May in both years. Three peaks were detected in ascospore dispersal in the period of examination which was clearly related to the Mills infection periods. On the basis of the incubation period’s length in April (15–18 days), the appearance of first symptoms had direct connection with the peak of the ascospore discharge. The largest number of symptoms were observed on those parts of the orchards where where the inoculum sources were accumulated.

• Effect of a nanotechnology-based foliar fertilizer on the yield and fruit quality in an apple orchard

  29-32.

  Á. Csihon

  I. Gonda

  I. J. Holb

  Views:

  552

  Nutrient management is a determining element of the technology in fruit production. Significance of foliar fertilization has been increased continuously over the last years, as it can improve directly the vegetative and generative performance of the trees. In this study we aimed to evaluate the effect of a nanotechnology-based foliar fertilizer (Bistep) with 1, 3, and 5 l/ha dosages on the yield and fruit quality parameters in an apple orchard during 2016 and 2018. According to our results, crop load increased with 29% in the third year of the experiment with the application of 5 l/ha Bistep treatment compared to the control treatments. Fruit weight was also improved in each year, as values of fruit weight in all treatments were higher than the control one (3.0-13.0% growth). Fruit surface color increased with 2-18% due to the foliar fertilizer. During the three years, leaf length was 9.5-9.9 mm on the control trees, as 9.8-10.4 mm was measured on the fertilized ones. In conclusion, yield and fruit quality can be improved in apple orchard using a nanotechnology-based foliar fertilizer.

• Economic aspects of applying hail protection nets in apple plantations

  99-101.

  F. Apáti

  M. Soltész

  Views:

  226

  The up to date intense apple growing in Hungary is capable to produce yearly about 500-1000 thousand Ft/ha income, which means that the investment of 4 000–5 000 thousand Ft is returned by producing 10-20% net income. The economic balance may, however, be upset by the damage caused by hail, quantitative and qualitative, with an apparently increasing frequency experienced in each third or fourth year. Estimates prove that each hail causing 50% damage may reduces the income proportionately to the capital by 1.5–2.0 percent points, which means a serious threat for the economy of apple production. According to calculations, a plantation producing 30–40 t/ha yields would not be able to raise incomes compensating the investment of 7.0–10.0 million Ft/ha, let alone the frequencies of hail damages. Consequently, 50–60 t/ha yields are needed to become successful, and in planning of new plantations those high yields are aimed with hail nets. An additional difficulty is represented by a lack of financial resources to install hail protection nets.

• Characterization of sunburn damage to apple fruits and leaves

  15-20.

  J. Racskó

  T. Szabó

  J. Nyéki

  M. Soltész

  P. T. Nagy

  Views:

  607

  The specific conditions of the formation of three different types of sunburn (sunburn browning, sunburn necrosis, and photooxidative sunburn) have been recently characterized on apple fruit. However, no information is still available on leaf damage. Therefore, the aims of this study were i) to extend the knowledge on fruit damage, ii) characterize leaf damage and iii) find relationship between fruit and leaf damage. The observations were made on 586 apple accessions in a gene bank orchard located in Hungary. The incidence of the three different types of fruit symptoms were recorded and based on the visual symptoms, two different types of leaf sunburn (sunburn yellowing and sunburn necrosis) were characterized. The most frequent type of fruit sunburn observed was sunburn browning. Photooxidative sunburn was found for less number of accessions, and only some accessions were affected by sunburn necrosis. Fruit were far more susceptible than leaves; (>60%) of the examined accessions were affected by fruit damage and (<3%) by leaf damage. Although a large number of accessions were affected, the percentage of fruit damaged within accessions was not that excessive; ~6% of the fruit assessed showed the symptoms of sunburn browning. Significantly fewer fruit were damaged by sunburn necrosis (~1%) or photooxidative sunburn (~1.4%) than sunburn browning. The percentage of leaves damaged within accessions were simlarly very low (~1%). Close relationship between fruit and leaf damage was found. Accesions with relatively heavily sunburned leaves usually had severe fruit damage as well. Leaves showing sunburn symptoms were usually closely located around those fruit which were sunburned severely. Leaf damage of sunburn was found on spur leaves in a great majority of the accessions damaged, shoot leaves did not seem to be susceptible to sunburn.

• Interaction of nutrient supply and crop load of apple trees (Malus domestica Borkh.)

  33-35.

  E. Szűcs

  T. Kállay

  Views:

  156

  Long term fertilisation trials were combined with storage experiments with 'Jonathan' apple trees and fruits to study influence of tree nutrition on quantity and quality of crop. The site of experiments is a typical Carpathian-basin environment with loamy silt soil, high lime content and arid summers. Conclusions has been drown from six years' set of data. Augmented levels of soil fertilisation increased cropping capacity of apple trees, however, the fruit load has not met with cropping capacity in every year. More the def cit came into view in crop load, less the fruit quality resulted in. The deficit in cropping capacity, however, could not have been determined with simple rates as fruit weight per trunk circumference or similar. Better determination was obtained where foliar nutrient contents were correlated to crop per tree figures. In general terms, the N and Ca content in leaves increased with yields when K and P content formulated reciprocally. When storage quality of 'Jonathan' apple fruits were related to crop load (kg/tree), influence of crop deficit became visible. As the crop load and foliar nutrient levels interacted, the fruit quality (number of disordered apples after 6 month of storage) subjected of both physiological phenomena. Higher determination degree were obtained when crop load was assessed together with single or multiple foliar analysis data.

• Analyses of temporal dynamics of brown rot development on fruit in organic apple production

  97-100.

  I. J. Holb

  Views:

  191

  In a two-year study, yield loss and temporal dynamics of brown rot development caused by Monilinia fructigena (Aderh. & Ruhl.) Honey were quantified and analysed in two organic apple orchards (Debrecen—Pallag and Debrecen—Józsa). The first infected fruits were observed at the beginning of August in both years and both locations, except for one occasion when the first infected fruit was found at the end of July. Temporal disease development was continuous up to harvest time in both years and locations. In the two years, pre-harvest yield loss on the trees amounted between 8.9% and 9.3% at Debrecen-Pallag and between 9.7% and 10.8% at Debrecen—Jozsa by fruit harvest. Incidence of infected fruits on the orchard floor ranged from 32.4% to 43.2% and from 53.3% to 61.9%, at Debrecen—Pallag and Debrecen—Józsa, respectively, by fruit harvest. Analyses of temporal disease progress showed that the best-fitted mathematical function was the power function in both orchards and years. Both parameters of the power function clearly demonstrated that incidence of brown rot on fruit increased faster on the orchard floor than on the tree. Moreover, the disease increase was faster at Debrecen—Józsa in most cases than at Debrecen—Pallag. Our results indicated that the strategy of disease management, the ripeness of the fruit and the presence of a wounding agent played an important role in the yield loss and in the temporal development of fruit disease incidence caused by M. fructigena in organic apple orchards. Biological and practical implications of the results are discussed.

• The effect of rootstock on the nectar production of apple cultivar `Idared'

  15-25.

  E. Nagy Tóth

  Zs. Orosz-Kovács

  Views:

  133

  Approaches based on the daily rhythm of apple flowers provide a new stage in nectar research, where the synchronous functioning of sexual organs is studied. In the flower biological studies the insect attraction of flowers was also studied. The two most important factors of insect attraction are the pollen- and nectar production of the flowers. From 1993 to 1998 we studied the food, that flower had to offer for the pollinating insects at different times of the day.

  Studies were carried out on 'Idared', one of the hybrids of 'Jonathan' apple cultivar. The fruit of 'Idared' is bigger than the fruit of `Jonathan'. It is bright red, transportable, has a bigger productivity and is not subject to Jonathan-spots. Concerning its inner characteristics, it is juicy, the flesh consistency is better than that of 'Jonathan', but its acid/sugar ratio is worse (Sansavini et al. 1981).

   

• Application of DNA markers for detection of scab resistant apple cultivars and selections

  59-63.

  H. Mattisson

  H. Nybom

  Views:

  109

  A DNA marker-based study was undertaken to identify the occurrence of major scab resistance genes in some apple cultivars and selections of importance for apple breeding. Unfortunately none of the RAPD-based markers previously reported to detect the V_a, V_b, V_r and V_x genes produced unambiguous results. By contrast, the CAPS marker MI8 produced the expected three bands in all cultivars and selections already known or suspected to have the V_f gene, as well as in the Russian cultivar 'Antonovka Polotora Funtovaja' suspected to have V_a resistance which however may be allelic to V_f. V_f-carrying selections and newly named cultivars 'Frida' and 'Fredrik' are grown successfully in Sweden without fungicides, suggesting that the V_r resistance breaking scab races 6 and 7 have not yet become a problem. The SCAR marker B12 detected the V_m gene in 'Prairifire', 'Rouville', clones 'OR45T132' and 'OR48T70', and selection '16-36-193'. The SSR locus 0102b10 detected one band at 118 by in 'Reka'. This is presumed to be identical to the V_r gene marker previously reported.

• Farm-scale evaluation of two widely used sanitation practices for reducing primary inoculums of apple scab in organic apple production

  15-18.

  I. J. Holb

  A. Rózsa

  F. Abonyi

  Views:

  204

  Effects of two widely used sanitation practices were evaluated at farm-scale level on leaf degradation and primary infection by Venturia inaequalis in an organic apple orchard (Eperjeske) on two apple cultivars (Jonathan and Prima) from 2011 to 2013. The tested sanitation practices were eradication of fallen leaves by collection and disc cultivation. Treatments of eradication of fallen leaves by collection and disc cultivation reduced signifi cantly (P< 0.001) leaf litter density with 70–85 and 40–55%, respectively, compared to untreated plots in both years. Above treatments in the same order reduced spring scab incidence with 40–50, and 10–20%, respectively, compared to untreated plots. Incidence of leaf scab in autumn was not signifi cantly lower (P< 0.05) in the treatments in the years.

• General principles in variety-association for intensive plantations of pomeceous fruits

  96-101.

  M. Soltész

  J. Nyéki

  Z. Szabó

  Views:

  301

  Under conditions of Hungary, more than 400 varieties of apple, pear and quince varieties have been observed for time of blooming and fertility relations in order to check the possibility of their use for intense plantations in different combinations with polliniser varieties. Low (below 3%) rate of self-fertility occurred at 65% of apple varieties. That partial self-fertility, however, is far from being sufficient to produce acceptable yield, thus allogamous pollination is absolutely necessary. The same is true for the rear and quince varieties grown in Hun­gary, too. The normal development requires the presence of viable seeds in the fruit set, most in quince, therefore, association of the right varie­ties is most important in that species. Apple and pear varieties are assigned according to their blooming time to 4, quince varieties to 3 groups. The yield of all three pomaceous species declines with the growing distance from the potential pollen source. In the intense plantations, the critical (maximum) distance to be observed is 20 m for apple and 15 m for pear and quince. In combining the placement of varieties, also the principles of a variety-specific cultivation are to be considered carefully. The double objectives are satisfied most by the system of Malus­pollinisers developed for intense plantations.

• The effect of storage to optical properties in case of two apple fruit varieties

  33-36.

  A. M. El Shal

  P. Riczu

  A. Nagy

  E. Sulyok

  Z. Szabó

  J. Nyéki

  Views:

  268

  The keeping quality of fruits is a very important factor in storage point of view, since it could be elongated the consumption time of fruits. In many cases the storage may be necessary, e.g. in short time it is not able to market due to the rich harvest, or all fruits could sell in markets throughout the year. The keeping quality of various fruit species is greatly different; moreover it could be observed some differences between the varieties as well. In our research, we have investigated the spectral properties of the external surface and fl esh of two ripe apple varieties – Jonagored and Granny Smith – before and after storage (about 3°C and about three weeks). The hyperspectral investigation was carried out with AvaSpec-2048 Fiber Optic Spectrometer. The experimental results represented the differences between healthy and chilling injured apple fruits. Furthermore, some indices were created to given countenance to the spectral differences.

• Anatomical study of the bud union in „Chip" and „T" budded 'Jonagold' apple trees on MM 106 rootstock

  27-29.

  Gy. Végvári

  K. Hrotkó

  Views:

  381

  The traditional methods for vegetative propagation of apple and its varieties are the T-budding, and the winter grafting, but this latter way is a difficult and expensive procedure.

  In our experiment carried out in the Fruit Tree Nursery Soroksár, the healing process of chip- and T-budded apple trees 'Jonagold' on MM 106 rootstock was studied.

  The budding (T- and Chip-) was made in the first week of August, samples for microscope examination were taken monthly after this time until leaf fall.

  The investigated part of plants was made soft with 48 % HF (hydrogenfluoride), then cross and longitudinal section were made and examined by microscope.

  Based on analysis of microscope pictures in case of Chip-budding, it was established, that development had started quickly after budding on the rootstock and scion too. But the callus originated almost entirely from the rootstock tissue as new parenchyma cells fills the gap between the two components of graft (scion and stock), becoming interlocked and allowing for some passage of water and nutrients between the stock and the scion. This quantity of callus in case of T budding was under the scion buds larger, than the Chip-budded unions, where the thickness of callus mass is uniformly thick round the chip. The large mass of callus pushes the scion bud outwards from the shoot axis, which later results in a larger shoot-curvature above the bud union.

  Following this process on the Chip-budding it can be observed also, that a continuity of the cambium is established between bud and rootstock. Then the newly formed cambium started typical cambial activity, forming new xylem and phloem.

  Later the callus begins to lignify, and it is completed within about 3 months after budding.

   

• Specialities of the vegetation start and level of primary fruit set affect fruit quality

  17-22.

  N. Rakonczás

  P. Dremák

  I. Gonda

  Views:

  188

  Thinning is a h ighly crucial point of the apple production technology. According to results of numerous studies the earliest thinning is deemed to have the best amending effects. There can be considerable difference between trees of the same cul tivar and age in a plantation in respect to their flowering, in the numbers of fruits set and also in their canopy volume. Thus it can be crucial -just l ike in the case of pruning- to establish a fruit thinni ng su i ted for specif ic characteristics of actual trees. This experiment was established to examine how does primary fruit set (fruit load before thinning) and further on specific (fruit/TCS cm2) and absolute (fruit/tree) fruit-load of the trees affect quality attri butes at harvest. Our experiment was establ ished in a plantation on medium-tight loamy soil in north-east of Hungary. Harvest date was determined w ith the joint observation of the calendar date, starch-index, flesh firmness, background colour and fruit weight. Three fruit-load levels were established based on local experience and on data of several years, I Ot/ha lower and higher besides the advised optimum yield in the same orchard with slender-spindle shaped 'Gala must' cultivar standing on M9 rootstock in 1m x 3,8 m spacing. In the establishment of the 15, 25 and 35t/ha fruit-load levels on 20-20 apple trees total number of fruits set was counted at each tree. After this number of apples due to be removed was defined using an objective index on the basis of trunk cross sections (fruit/TCScm2) (Lafer, 1999). The following attributes were measured: weight (g), flesh firmness (lb/cm2) total soluble solid content (Brix %) and total titrate-able acid content (g/J).From the data on sugar and acid content quality index (Pomona value) was determined (Thialult, 1970). We could ascertain, that in an orchard, of the same aged but in concern to trunk cross sections somewhat different trees besides the specific index (apple/TCS cm2 the absolute fruit load (fruit/tree) can also be an important data, that has considerable effect on the internal quality. Secondly we could observe, that higher level of fruit load before thinning (primary fruit set) negatively affects quality index of the apples irrespective of the specific fruit load level (fruit/cm2 TCS) set later. Results underlines necessity of the earliest chemical thinn ing.

• Anatomical study of the leaves and petioles of scab resistant and susceptible apple cultivars

  53-57.

  M. Tóth

  P. Gracza

  Views:

  151

  Anatomic studies have been performed on the leaf blade, petiole and annual shoot on six apple cultivars by means of scanning electron as well as light microscope. Four of the cultivars examined are resistant to scab (Florina, Freedom, MR-10, MR-11), whereas two of them are susceptible (Jonathan and Idared). Preliminary results suggest that differences in the width of cross sections of leaf blades, in hairyness, in the shape and size of epidermal cells, moreover, in the cross sections of petioles and shoots are considerable. Some of the anatomical properties seem to be correlated with scab resistance or susceptility of the respective cultivars. Therefore, further studies extending to other cultivars may corroborate our claims to find causal relations between anatomical traits of the leaves and disease, especially scab resistance of apple cultivars.

• Floral biological investigations of apple cultivars in relation to fire blight

  9-14.

  Zs. Orosz-Kovács

  A. Farkas

  T. Bubán

  P. Bukovics

  E. Nagy Tóth

  H. Déri

  Views:

  165

  Floral activity was studied in two apple cultivars: an Erwinia-tolerant (Treedorn') and a sensitive one (`Sampion'). Since more types of protogyny occur in apples, the period of stigma activity is different. Papillae of the exposed stigma in flowers of 'Freedom' function longer (usually more than a week) than in the delayed homogamous `Sampion'. Despite of this, cv. 'Freedom' is tolerant to Erwinia amylovora (Burr.) Winslow et al., suggesting no relationship between the floral biological type (including the exposure and longevity of stigma) and the infection by E. amylovora. According to SEM micrographs, nectary stomata in `Freedom' are already open in the flower bud, where nectar secretion starts and continues until the senescence of the stigma. However, the long period of nectar secretion does not create optimal conditions for bacterial growth, since nectar production is scant in the flowers of 'Freedom'. The surface of the nectary, its nectar-retaining capacity, and the amount and concentration of nectar may influence the susceptibility of apple cultivars. It is manifested well by the smooth nectary surface with nectary stomata rising slightly above the epidermis in flowers of cv. 'Freedom', contrasting the wrinkled, striate nectary surface with slightly sunken stomata in the flowers of 'Sampion'.

• Effects of irregular cropping on nutrient uptake and status of apple trees

  41-44.

  P. T. Nagy

  Z. Szabó

  M. Soltész

  J. Nyéki

  Views:

  208

  Produce of harmonic nutrient balance and status of trees is basic task of growers for qualified fruit growing. The role of crop loaded is essential to grow the productivity of trees without nutrient disorder or other nutritional problems. To reduce the frequency of biennial bearing there are some ways (site and species selection, crop regulation, irrigation, nutrition etc.) from them one is the best easy way the proper site and species oriented nutrition. Sometimes the responsible for irregular cropping is the insufficient fertilization. Observed irregular cropping at two apple cultivars (Malus domestica Borkh., cv. ‘Summerred’ and cv. ‘Mutsu’) in an integrated apple orchard at Hajdúnánás-Tedej, in 2007 resulted a chance to determine nutritional status of “bearing” and “non bearing” trees and investigate the effects of irregular cropping on nutrient uptake and possibilities of correction. Our results pointed out that irregularity is connection on nutrition status of trees. Irregular cropping results in insufficient nutrient uptake and disharmony of nutrients. For this reason, the establishment of nutrient status of “non bearing” trees is could permit a chance to correct and improve the nutrient supply of trees which help to breakdown the vicious circle of irregularity.

• The effect of Regalis® (prohexadione calcium) on the reduction of fire blight (Erwinia amylovora) severity in apple trees

  61-66.

  P. Sobiczewski

  T. Bubán

  Views:

  177

  Due to the lack of effective and non-phytotoxic materials for control of the blossom and shoot blight phase of fire blight in pome fruit trees, two novel control strategies have emerged: shoot growth retardation by bioregulators and applying resistance inducer compounds. Prohexadione calcium (ProCa) is the active ingredient of the bioregulator Regalis^® registered in several European countries. The reduction of shoot growth elongation is the most obvious effect of ProCa. Furthermore, it causes significant changes in the spectrum of flavonoids and their phenolic precursors, leading to the considerable reduction of susceptibility to fire blight.

  In Poland, potted one-year-old apple trees of cvs. Gala Must grafted on M.26 and Sampion on M.9 (in 2001) as well as Gala Must on P.60 (in 2002) were treated with Regalis® at a range of concentration of 250, 150 or 150 + 100 ppm, respectively. The inoculation of shoots was made with the strain No.691 of E. amylovora (10⁷ cfu/ml), on the 7th and 21st'day after treatments with Regalis. In Hungary, during the years of 2002 and 2003 one-year-old container grown apple trees of the cvs. Idared/M.9 and Freedom/M.9 were treated with the prohexadione-Ca, the active ingredient of Regalis® 100, 150 or 200 ppm, two weeks before inoculation with the Ea 1 strain of E. amylovora (10⁷ cfu/m1).

  In Poland, the suppression of fire blight in shoots reached up to 80%, depending on concentration and application time of Regalis®. In Hungary, the effect of prohexadione-Ca treatments, determined by the length of necrotic lesion developed, proved to be better than that of streptomycin used for comparison.

• Effect of Erwinia amylovora infection on peroxidase enzyme activity in resistant apple cultivars

  37-39.

  K. Kása

  M. Hevesi

  M. G. Tóth

  É. Stefanovits-Bányai

  Views:

  157

  Two apple cultivars that display enhanced resistance to fire blight (causal agent: Erwinia amylovora) were selected. The aim of the present study was to characterize the peroxidase (POD) enzyme activity of `Szemes alma' (a historical cultivar) and MR-03, (a Hungarian multiresistant hybrid of 'Prima') and compare them to susceptible 'Jonathan M 40' and resistant 'Remo' controls. Peroxides enzyme activity during E. amylovora infections was investigated in artificially infected apple shoots. Increases in enzyme activities were observed in a `Jonathan M40' and in 'Remo', MR-03, `Szemes alma' cultivars. There was a consistent relationship between total enzyme activity and fire blight disease severity. High activity of the peroxidase was positively correlated with the degree of resistance to fire blight. A general hypothesis that POD activity is related to fire blight susceptibility/resistance is supported by our results.

• Post-storage sensory quality of apple varieties

  54-57.

  Z. Kókai

  P. Sass

  M. Erdélyi

  Views:

  124

  The changing situation of apple production in Hungary has given rise to a great demand for new varieties. Besides bearing capacity, fruit quality and suitability for new training systems, consumer preference is one of the grower's main considerations. Growers need reliable information in order to choose the appropriate variety, so consumer tests have become essential. Altogether, 1 I traditional and new varieties were involved in this project. In the first part of the experiment, panelists ranked the coded samples according to their appearance. In the second part, apples were cut into unpeeled slices and the samples were also coded. The assessors were asked to taste them and rank them again. The sensory tests were held after three different storage periods.

• Role of organosilicone surfactant in apple scab control under scab conducive weather conditions

  23-25.

  I. J. Holb

  Views:

  200

  Fungicides of integrated fruit production (dithianon, captan, and diclofluanid) and an organosilicone surfactant were compared in spray schedules from green tip until summer in order to control apple scab caused by Venturia inaequalis and to evaluate their phytotoxicity on fruit. Sixteen sprays of 1.8 kg ha^-1captan, 0.41 ha^-1 dithianon, and 1.8 kg ha^-1 diclolfluanid significantly (P=0.05) reduced the incidence of leaf or fruit scab compared to unsprayed products. All fungicides applied with organosilicone at 0.1% resulted in lower incidence of scab on young and older leaves as well as on harvested fruit, but these were not statistically always better than fungicides applied alone. In case of diclofluanid, the fungicide applied with organosilicone at 0.1% resulted in significantly lower (P = 0.001) incidence of scab on young and older leaves. Diclofluanid applied with organosilicone at 0.1% gave the best scab control on leaf and fruit. Treatments applied with fungicides alone had no significant effect on plant phytotoxicity compared to untreated control. All fungicides applied with organosilicone at 0.1% increased (P = 0.05) fruit damage compared to untreated control or fungicide applied alone, though these were not always significantly different. In case of percentage of fruit russet, treatment of dithianon 0.4 1/ha + 0.1% organosilicone significantly increased fruit russet, while fruit russet index significantly increased in the treatment of diclofluanid 1.8 kg/ha + 0.1% organosilicone compared to untreated control. In sum, application of surfactants can help to increase efficacy of scab fungicides; and consequently, to reduce the risk of fungus infection under high scab disease pressure. This fact may also be helpful in fungicide resistance management and reduced-spray programs with accurate scab warning systems.

• Effects of different cytokinins on the shoot regeneration from apple leaves of 'Royal Gala' and 'M.26'

  69-75.

  J. Dobránszky

  I. Hudák

  K. Magyar-Tábori

  E. Jámbor-Benczúr

  Zs. Galli

  E. Kiss

  Views:

  214

  The effects of different types of cytokinins on the shoot regeneration from leaf explants of apple scion 'Royal Gala' and apple rootstock 'M.26' were evaluated. Regeneration media contained either thidiazuron, or 6-benzylaminopurine, or meta-topolin, or zeatin, or kinetin, or their N⁹-ribosides, respectively, in the concentration range 0.5 to 8.0 mg 1^-1. Effects of 'these cytokinins were evaluated on the percentage of regeneration (R%) and that of vitrification (V%) and on the number of regenerated shoots per explant (SN). Organogenetic index (0I) calculated from these data was used for the evaluation of efficacy of cytokinins. The course of shoot organogenesis also was followed using stereomicroscope. Types and concentrations of cytokinins applied in the regeneration media influenced each parameter significantly and the regeneration answer was strongly genotype-dependent. The best regeneration (SN: 11.08, 01: 7.5) was achieved in `Royal Gala' by using TDZ in concentration of 0.5 mg 1<sup>-1</sup> (2.271,1M). There was a clear relationship between the effect on the regeneration efficacy and the chemical structure of cytokinins considering classical cytokinins, namely N<sup>9</sup>-ribosides applied in less concentration than non­ribosides have the same or best regeneration effects except for 6-benzylaminopurine riboside. However, similar relationship could not be detected in the case of 'M.26'. SN was the highest (3.22) using 6.5 mg 1<sup>-1</sup> (18.2011M) 6-benzylaminopurine riboside or 8.0 mg 1<sup>-1</sup> (21.44 µM) meta-topolin riboside (3.18). SN was not significantly lower (3.12) by using 2.0 mg 1<sup>-1</sup> (9.08 1M) TDZ, however, OI was about half as big (0.63 compared to 1.29 or 1.74 with 6-benzylaminopurine riboside or meta-topolin riboside, respectively). 'Royal Gala' had higher organogenetic ability, than `M.26': 3.5-fold higher shoot number per explant and more than 4-fold higher organogenetic index was reached with this cultivar than with 'M.26'. Moreover, the similar developmental stage of shoots could be observed 3-5 days earlier than in 'M.26' and if explants of 'Royal Gala' were further cultured with 3 weeks, SN increased from 11.08 to 24.42 on TDZ-containing regeneration medium, which might suggest higher organogenetic ability, too.

• Molecular identification of old Hungarian apple varieties

  37-42.

  B. Wichmann

  Zs. Galli

  S. Molnár

  Zs. Galbács

  E. Kiss

  T. Szabó

  Heszky L.

  Views:

  256

  Altogether 40, mainly old Hungarian apple varieties were screened with six previously described microsatellite markers. A total of 71 polymorphic alleles were detected (average 11.8 alleles/locus) and the heterozygosity of markers averaged very high (0.8). The genetic variability among the genotypes proved to be so remarkable that as few as three markers from the applied six were enough to distinguish between the 40 varieties. This was also confirmed by the cumulative probability of obtaining identical allele patterns for two randomly chosen apple genotypes for all loci, which value was quite low: 2.53 x 10^-5. The molecular identification of these genetically very different old apple genotypes could be very useful in future breeding programs.