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  • Results of cherry rootstock evaluations in Hungary
    11-14.
    Views:
    462

    The paper gives a review on the results of the latest rootstock evaluation projects in Hungary. Several cherry rootstock evaluation projects were carried out in Hungary during the last two decades. The evaluated rootstocks are partly mahalebs selected in Hungary, but more or less all the most important new rootstocks from different countries are involved. The aim of these evaluation projects was to find appropriate rootstocks in a wide range of vigour for our climate and soil conditions. The conclusion of the last 20 years of research in Hungary proved just the opposite of believes, that high density orchard can only be planted with dwarfing rootstocks. Before choosing the right rootstock the most important is to consider adaptability, precocity and productivity. Dwarfing and semi-dwarfing rootstocks showed proper results only with irrigation or very good site conditions. These rootstocks are very precocious, but branches form easily blindwood. This must be corrected by severe pruning in the first years. The relatively small leaf surface area can also be disadvantageous, but it can be controlled by pruning, fruit-thinning, irrigation and fertilization. After studying different rootstocks semi-vigorous rootstocks seem to be the most adequate for different site conditions in Hungary. Fast initial growing and competent precocity are their favourable characters. From the vigorous group of clonal mahalebs or seedlings are highly recommended first of all for poor site condition (sandy, lime soils with high pH). They turn to bearing early and easy to find them in the Hungarian nurseries. But on vigorous rootstocks trees might need stronger summer pruning.

  • Molecular identification of old Hungarian apple varieties
    37-42.
    Views:
    821

    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.

  • Study of Erwinia amylovora colonization and migration on blossoms of susceptible and tolerant apple cultivars
    15-19.
    Views:
    323

    The stigmata of detached flowers of susceptible and tolerant apple cultivars were inoculated with about 104 gfp labeled Erwinia amylovora . There were no apparent differences in the colonization, multiplication and survival of the bacteria on the stigmatic surface of the culivars. Bacteria were washed down to the hypanthium surface 24 hours after inoculation. The visual symptoms of the infection were the discoloration and shrinkage of the floral parts. The gradual browning associated with the infection appeared first on the surface of the hypanthium followed by the discoloration of the style. The color of the filaments turned into brown only 120 hours after the inoculation. Bacterial cells were not detected in the tissues of the styles and filaments. The traits of the hypanthium surface are of prominent importance in the progression of the infection. The wrinkled surface, the convex shape of the outer epidermal cell walls with thin cuticle and the sunken stomata helped to preserve a water film for a longer period providing medium for the motility of the bacteria in the susceptible cultivar. Bacteria were restricted to small water droplets on the flat and waxy surface of the hypanthium of the tolerant cultivar and only a few were able to enter the tissues.

    Large bacterium aggregations were detected in the intercellular spaces of the parenchyma of the susceptible cultivar 48 hours after the inoculation. In the next period the Erwinia amylovora cells gradually invaded the intercellulars of the hypanthium wall, the wall of the ovary and the pedicel. Low level of bacterium aggregation was found in the intercellulars of the tolerant cultivars. It is suggested that the progression of the infection was inhibited also by physiological factors.

  • Organoleptic evaluation of pear varieties grown at different sites
    33-37.
    Views:
    1099

    It was stated as a summary that a system of testing pear varieties on scale of 100 degrees, weighing 11 properties, gives a comprehensive information on qualities of pear varieties. The points of the form to be filled out, distinguishes the appreciation of accessory flavours and tastes from the main properties. Under the title of taste, sweet and acid taste are evaluated separately. The presently used system is a step forward as the composed characters do not influence the judgement of each other. In the representation of results, the 100 degree system was more efficacious than the usual 5-point system because there was no need of using fractions, and the graphic profile is more expressive, so the commodity is better visualised. The assembly of the jury was divided into two groups as below and above 35 year old persons. The two groups judged differently the acidity, sweetness and the thickness of the fruit peel. It was suggested that the choice of the produce should consider the differences in taste and give up the idea of being equally favourable for both groups. The samples of different growing sites revealed that the best quality is produced at Nagykanizsa, and this capacity would be able to supply the market also in the large super-markets and chain of department stores in Hungary.

  • Organic versus integrated apple growing: I. differences in soil and leaf parameters
    57-60.
    Views:
    1796

    The aim our study was to establish whether significant differences in nutrients uptake and quality of soil and leaf exist between organic and integrated grown apples. The study was performed at the orchard Fruit Research Station, University of Debrecen, at Debrecen-Pallag during 2002–2004. Macro and micro elements were measured in soil and plant samples. Analyses of variance of soil nitrogen data indicated highly significant differences between the two management systems (P < 0.001) for each examined nitrogen fraction. Analyses of variance of soil phosphate data indicated significant differences (P < 0.05) between the two management systems for orto-PO4 3– contents. Our data indicated that highly significant differences between the two management systems (P < 0.001) for magnesium, copper, and zinc; while significant differences between the two management systems was at P = 0.007 for calcium. Three year’s data of leaf phosphorus, sulphur and zinc were not shown significant differences between production systems. Nevertheless manganese and copper contents of leaves were higher in the organic orchard compared to the integrated one.

  • Effect of black plastic mulch and raised bed on soil temperature and yield of sweet pepper
    107-110.
    Views:
    307

    A field study was conducted in Central Hungary in 2001 and 2002 in order to evaluate the effects of black plastic mulch and raised bed on soil temperature and on yield and fruit quality of sweet pepper (Capsicum annuum L. cv. `Kárpia'). The experiment was a complete block design with four replicates. Four different technologies were used as treatments: raised bed with black PE mulch, raised bed without mulch, level ground with black PE mulch and level ground without mulch. In both years soil temperature was the highest in the covered raised bed treatment, about 2 °C higher than in the uncovered raised bed. Optimum soil temperature requirement of sweet pepper roots was met to the highest degree in case of the covered raised bed, 26-28% of the total growing period. The more favourable soil temperature conditions resulted in better yield, compared to the uncovered level ground treatment the covered raised bed treatment produced 19% and 14% higher yield in 2001 and 2002, respectively.

  • Effect of the placement of self-incompatible apricot varieties on their yield in commercial plantations
    82-86.
    Views:
    1280

    Earlier studies concerning self-, free- and cross- fertilization of apricot varieties grown in Hungary, proved the existence of self-sterile as well as self-fertile varieties within the recommended assortment. The self-sterile and partially self-fertile varieties should be planted in association with polliniser varieties, only. The present paper reports about the yields of trees of the widely grown, self-sterile local variety, Ceglédi óriás (Giant of Cegléd), depending on the distance of adequate polliniser trees. In the univarietal, 27 row-wide block of the relevant variety, an efficient polliniser, Magyar kajszi was planted to the 10th and 19th row. In the close vicinity, another block of polliniser, Rózsakajszi C. 320 was located. The number of fruits set per tree has been counted or estimated in two consecutive years. In both seasons, the yield of the Ceglédi óriás trees diminished with the growing distance from the nearest polliniser trees. Those trees in the center of the block, between the two (10th and 19th) rows of Magyar kajszi bore acceptable yield (40 kg/tree in 1987), however, considerable reduction of the number of the fruits set was stated already in the 4-5th row from the polliniser away. Similar gradient of fruit set was apparent in relation to the neighbouring block of Rózsakajszi C 320. The beneficial effect of the vicinity of polliniser varieties was obvious as far as the distance of the 10th row. Taking into consideration the self-sterility, the early blooming time and the poor fertilization of the variety Ceglédi óriás, a planting design of associating it with at least two polliniser varieties (e.g. Gönci magyar kajszi and Ceglédi bíbor) is highly recommended. On the basis also of earlier results, a proposal has been developed for the association of apricot varieties as recommendations for optimising yields. Blooming time, fertilizing potential, schedule of the picking season and market possibilities have to be considered simultaneously.

  • Effects of different rootstocks on the morphologic parameters of watermelon grafts during transplant production
    69-73.
    Views:
    410

    Before Hungary joined the EU watermelon production was a key sector of the Hungarian vegetable industry. Its production area shrank by nearly 60 % since 2004, it is only 5000 ha today. Stable and reliable market failed to evolve in the last years and extreme weather events occurred more frequently. An unfavourable growing season can notably affect the production volume of the next season. Information gathered in the last years support the assumption, that suitable stocks can help eliminate the issues caused by extreme weather or short-term crop rotation. Choosing the right grafted or non-grafted transplant is not enough any more, growers also have to select stock. In fruit and vine production choosing the stock, which is the most suitable for the technology is evident and this approach should be widely adapted by watermelon growers as well. In this research we investigated the growth parameters of different watermelon stocks and their effect on the scion during the transplant production. Measurements were carried out on seven different stock-scion combinations of the scion ’Topgun F1’ hybrid. Two of the stocks were interspecific (Cucurbita maxima × Cucurbita moschata) and five stocks were Lagenaria-type (Lagenaria siceraria) stocks. We made and recorded observations of the transplants’ length (cm), diameter of the stock and scion (mm), number of leaves (piece), root length (cm), root mass (g) and shoot mass (g). We concluded that early pricking out of transplants with interspecific stocks is successful due to their hardiness and vigorous growth. The effect of the ’Shintosa camelforce F1’ interspecific stock was outstanding. Furthermore, the results confirmed the practical observation that the root system of interspecific stocks grow vertically more allowing them to take up water and nutrients from lower soil layers in poor sandy soils. From the Lagenaria group the root system of the ’DG-01 F1’ was similar to the interspecific stocks’. It can be grown even in sandy soil, however other Lagenaria-type stocks are more suitable for production in hard soils with nutrient supply because of their compact root system. This study can serve as a basis for further research in the topic that can conduce to site- and technology-specific stock selection.

  • Pilot study for irrigation modelling of a pear plantation
    81-84.
    Views:
    4201

    Our investigation was carried out in the area of Fruit growing Research and Consultant non-profit company, at Újfehértó. The pear requires large water quantity, but this pear plantation hasn’t irrigation system not yet. This study reviews the drainage conditions of the area based on digital elevation model, and examined the canopy cover of pear trees by evaluating of the hyperspectral image. Our aims were to determine the exact watershed based irrigation modelling and determining of the canopy% of the pear orchard to facilitate a precision irrigation decision support system.

  • Influence of aromatic cytokinins on shoot multiplication and their after-effects on rooting of apple cv. Húsvéti rozmaring
    84-87.
    Views:
    580

    Different aromatic cytokinins (BA, BAR, TOP and KIN) were tested alone or in combination for the shoot proliferation response of ‘Húsvéti rozmaring' apple scion. The best multiplication rate was achieved by dual cytokinin application (1 mg 1-1 BA + 1.5 mg 1-1 KIN). The rooting capacity was affected considerably by the position of shoots: transfer of the three-week-old shoots to the same or other proliferation medium in vertical position inhibited the following rooting totally. Post-effects of different cytokinins (BA and TOP) on subsequent rooting could be detected: BA increased the number of roots markedly, while TOP resulted in significantly longer roots.

  • New sour cherry cultivars selected from local sources
    79-80.
    Views:
    638

    New sour cherry cultivars selected from local sources

  • Hungarian fruits and vegetables of high anti-oxidant activity as functional foods (Review article)
    13-21.
    Views:
    1525

    Recently, projects aiming to enhance the consumption of fruits and vegetables are intensified. Experts agree in the principle of fresh vegetable foods being a valid panacea in averting risks of ailments as well as curing immune-insufficiency, inflammations, moreover, certain cancerous processes. It is generally accepted that among substances of biological activity the anti-oxidant compounds such as vitamins C, E and carotenoids, etc. have the major role in this process. Hungarian agriculture has outstanding chances in utilising its natural as well as cultivated plant resources and favourable climatic conditions. It would be, however, necessary to build up a databank of anti­oxidant substances found in fruits and vegetables and including the modifying effects of technology, growing site, variety, etc. The concept of promoting the trade of Hungarian food-specialities as "Hungaricum" needs, urgently, the aid of a databank of that kind. Some of those excellent products are for instance the sour cherry, pepper and onion. They enjoy high priority as "Hungaricum" in the EU and it should be enhanced by intense and consequent research work, which may prove their role as functional foods. The USA is the leading country in research on the anti-oxidant substances of sour cherries, and up to now more than 17 compounds have been found in Hungarian varieties among others. In pepper fruits used as vegetable and source of vitamin C, the analyses are still lacking because research of the past concentrated on the products of milled spice pepper. Onion and garlic are entirely unexplored in this respect. It should be noted that availability of these fresh products in the moderate climate is restricted to a relatively short season. For that reason, some processing and preservation methods are needed in order to use those fruits and vegetables as functional foods all around the year. The scientifically founded endeavour as a solution of the questions mentioned is stimulated by vigorous commercial interests as well as by the urgent needs of the consumers to improve their health.

  • A short introduction of new apple varieties obtained
    135-137.
    Views:
    703

    A short introduction of new apple varieties obtained

  • Relationship beetwen the phenological features of pear cultivars and the main meteorological parameters in a gene bank with 555 pear
    59-63.
    Views:
    1061

    The trees observed are grown at Ujfehert6, Eastern Hungary in a gene bank with 555 pear cultivars. Each of the cultivars was monitored for its dates of: the beginning of bloom, main bloom and the end of bloom and ripe phenophasis separately between I 984 and 2002. We analyzed the statistical features, frequency, distribution of these phenophasis and its' correlation the meteorological variables bet ween the interval. During this period the meteorological database recorded the following variables: daily mean temperature (°C), daily maximum temperature (0C), daily mini m um temperature (0C), daily precipitation (mm), daily hours of bright sunshine, daily means or the differences between the day-time and night-time temperatures (0C). For the analysis of data the cultivars have been grouped according to dates of maturity, blooming period as well as types of the seasons. Groups of maturity dates: summer ripe, autumnal ripening, winter ripe cultivars. Groups of blooming dates: early blooming, intermediate blooming, late blooming cultivars. At all the separated groups we analyzed the relationship between phenophasis and meteorological variables. During the 18 years of observation , the early blooming cultivars started blooming on 10-21 April, those of intermediate bloom date started flowering bet ween 20 April and 3 May, whereas the late blooming group started on 2- 10 May. Among the meteorological variables of the former autumn and winter periods, the winter maxima were the most active factor influencing the start dates of bloom in the subsequent spring. For the research of fruit growing-weather relationships we used simple, well known statistical methods, correlation and regression analysis. We used the SPSS 1 1.0 software for the linear regression fitting and for calculation of dispersions as well. The 1ables made by Excel programme.

  • Enrichment trials with straw substrate to produce Agaricus bisporus (Lge., Sing.)
    7-9.
    Views:
    240

    Everywhere in the world button mushroom is cultivated on heat-treated horse manure or on a compost mixture of straw, horse manure and chicken manure. In the ZKI trials continued on straw which seemed to be a simple and cheap substrate. To improve yield the N-content of the straw was increased by mixing it with wheat bran, alfalfa flour and ProMycel. Enriching agents were added to the dry heat-treated straw (100 "C) at 1, 2, 3 weight per cent. All the 3 agents increased yield as related to control. The highest yield was obtained with ProMycel.

  • Floral biological investigations of apple cultivars in relation to fire blight
    9-14.
    Views:
    400

    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'.

  • Assessment of apple varieties based on consumer judgement in integrated production for fresh consumption
    71-74.
    Views:
    1155

    In a former paper we treated the same relation comparing varieties frown in the biological or organic system of growing, now the tests have been performed with samples grown by the integrated system. The scores registered properties as taste, skin, colour, consistency and size. In addition, we also explored the relation between general impression and the individual properties.As first purpose, we started with collecting primary data on 15 samples taken from fruits grown by the integrated method and kept over 60–90 days in a store, then offered to the consumers. The test is based on an organoleptic assessment (records are registered in a questionary). The individual judgements are processed and coefficients of correlation between the traits (taste, skin, size, colour) calculated. The validity of the mathematically proved relations is considered to be decisive in judging the preferencial consumption of fruits.

  • Single and dual effects of different cytokinins on shoot multiplication of different apple scions
    76-78.
    Views:
    597

    Shoot multiplication responses of three apple scions to different concentrations of BA and BAR as single source of cytokinins and in combination with two concentrations of KIN were studied. The effects of hormones depended on genotype, type and interactions of different cytokinins. Use of BAR significantly enhanced the shoot multiplication of cv. Jonagold (6.5 shoots per explant). The multiplication rate of cv. Jonagold could not be improved by using the combination of BAR and KIN. The best proliferation was achieved by 1.0 mg 1-1 BA combined with 1.0 mg 1-1 KIN of cv. Prima..(8.1) and of cv. Galaxy (10.4).The effect of 0.5 mg 1-1 BA along with 1.5 mg 1-1 KIN was similar on multiplication rate (10.9) of cv. Galaxy.

  • Analyses of Hungarian sour cherry germplasm with simple sequence repeat markers
    27-31.
    Views:
    1354

    Twenty-four sour cherry cultivars (genotypes), belonging to four cultivar groups were fingerprinted using microsatellite markers. All genotypes have been arisen from the Carpathian basin, which could be secondary gene centre of sour cherry, since its progenitor species, ground cherry and sweet cherry overlap here. Five SSR primer pairs, earlier used for fingerprinting Turkish sour cherry germplasm were tested. None of the five primer pairs showed any polymorphism within the cultivar groups. The primer pairs were able to distinguish between the cultivar groups. The Oblacsinszka and the Cigánymeggy cultivar groups were the most difficult to separate, while the Pándy cultivar group was the most distinguishable.

  • Variability and differences of growth vigour in the set of 36 genotypes of apricot (Prunus armeniaca L.).
    30-34.
    Views:
    222

    Growth vigour of 36 apricot cultivars and new hybrids grafted on apricot seedling rootstock (Prunus armeniaca L.) was evaluated on the base of measurements of stem girth from the 411' to the 10th year after planting. There were differences in growth vigour of genotypes under study. In the evaluated set of genotypes the control cultivar 'Veecor may be classified as a genotype with below-average growth vigour. Only four genotypes (-Reale d'Imola-, Sanagian -Moldavskii krupnoplodnyl and 'LE-2385') were found with significantly higher growth vigour than that of control cultivar 'Veecot' in years of the end of experimental period. Two genotypes (Farmingdale', -LE-SE0-24') were found with significantly higher growth vigour only at the beginning of experimental period and one cultivar ('Vivagold-) with significantly lower growth vigour in the first four years. Genotypes with different growth vigour can be used in further breeding programmes and/or as components inhibiting or supporting the growth in indirect vegetative propagation. Within the whole experimental period, the rank of growth vigour of genotypes practically did not change. This was demonstrated by highly significant or significant coefficients of correlation existing between individual pairs of years (r=0.32+ to r=0.96++). As far as the time difference between years in individual pairs of years was higher, the correlation coefficients were lower. In individual years, variability of growth vigour was relatively low and ranged from 9.83 to 13.64%.

     

  • Large variations in antioxidant capacity and contents of Hungarian sour and sweet cherry cultivars
    25-28.
    Views:
    1137

    Sour cherry (Prunus cerasus L.) cultivars grown in Hungary are of local origin while most sweet cherry cultivars in Hungary are introduced from other countries.A great phenotypic variability is displayed by both species. In the present study, we analyzed 10 sour and 9 sweet cherry cultivars for their antioxidant capacity, total polyphenolics (TPC) and total anthocyanin (TMAC) contents. In general, sour cherries showed higher levels of antioxidant capacity, TPC and TMAC. The anthocyanin contents varied from 0.16 to 6.85 and 1.41 to 127.56 mg/100 g for sweet and sour cherries, respectively. However, TMAC generally seems to have a limited influence on the antioxidant capacity of cherries.An amarelletype sour cherry, ‘Pipacs 1’ showed the highest antioxidant capacity (21.21mmolAA/l) and TPC (44.07mgGA/l) in contrast to its lowanthocyanin content. The detected diversity presents a choice that can satisfy different consumer preferences, and meet specific nutritional requirements.

  • Researches concerning the selection of some nectarine varieties as genitors for the breeding program in Romania
    44-46.
    Views:
    197

    Researches concerning the selection of some nectarine varieties as genitors for the breeding program in Romania

  • Economic figures of sour cherry production at national level of Hungary
    107-109.
    Views:
    396

    After the political changes of 1989, economical processes impaired heavily the Hungarian fruit growing branch, more particularly production of sour cherry. Paralleling with the increasing mass of production, producer’s prices dwindled drastically. At present, Hungarian growers cannot cover the costs of production, nay, hardly raise income. My purpose was to analyse the cost and income relations of the sour cherry branch during the period of 2002-2009 years in order to find out what are the decisive features, which reveal the trends to be considered. The data presented in the paper are means of a heterogeneous population of values, which cannot be utilised for immediate use in management, but they may reveal the challenges and tendencies of economics of the branch.

  • Selection of the chance seedlings of `Mézes körte' (Pyrus communis L.) from the gene bank of Keszthely
    21-27.
    Views:
    803

    We have concluded the selection tests of the `Mézes körte' seedlings planted in the spring of 2006, with special emphasis on the cotyledonary, foliage leaf and the height of plant. Out of the 75 seeds planted in rows, there were 40-45 pieces growing out, so during the first cotyledonary test we had to calculate with almost 40% decay. On 12th April 2006, we recorded some of the important characteristics of the seedlings in their cotyledonary stage which characteristics were important from the point of view of selection (cotyledonary form, cotyledonary length, cotyledonary thickness, cotyledonary colour, cotyledonary petiole length, cotyledonary petiole thickness, cotyledonary petiole colour). The above morphological characteristics are shown in Table No. 1-6. We have also tested the seedling in foliage leaf state, paying special attention on the development stage of the plants (colour of foliage leaf , height of plant). We have completed statistical calculations of the two above mentioned characteristics. The result of that is summarised in Table No. 8-9. The variation coefficient show smaller value in the case of the foliage leaf number (15-32%), while the wider range of spread of the data referring to the height of the plant is shown by the 33-61% CV values. On charts No 4-9. we present the relationship between the height of the plant and the number of foliage leaf, as well as the differences between the two graphs. Based on the above charts and graphs it can be defined that the 40% destruction of the developing seedlings during the period till the next measurement reached 70-80% level. In spite of this however some seedlings showed strong and balanced growth (A44, B42, C25, D16, E5, E39, F38), the further testing and selection of those is to be completed in the future.

  • Prediction infection risk on the basis of weather-related factors and Erwinia amylovora colonization in apple and pear flowers
    39-54.
    Views:
    328

    Current infection risk prediction models utilize environmental parameters and field records, but do not take into account the estimated inoculum potential within the orchard. The object of this study was to survey the accuracy of three simple prediction methods under Hungarian climatic conditions, which could easily be used by the farmers. We also tested whether the accuracy of infection risk predictions can be improved by taking into consideration the incidence and/or rate of flower colonization by Erwinia amylovora.

    After preliminary investigations in 1999-2001, data concerning the weather-related infection risk were recorded in 5 apple and 1 pear orchards in 2002, and in 12 apple and I pear orchards in 2003. The weather data were processed by the easy-to-use risk assessment models of the mean temperature prediction line (MTL), Smith's Cougarblight 98C and Billing's integrated system (BIS), and by the MaryblytTM 4.3 computer-assisted model for reference. The population size of E. amylovora in the flower samples was estimated within an order of magnitude by PCR.

    For all years and orchards tested, Maryblyt indicated 35 days on which there was an acute infection risk. The same days were indicated by all 3 methods in 23 cases (66%), 8 days were indicated by 2 methods (23%) and 4 days were indicated by 1 method only. A similarly good correlation was found for prediction of the date of the first massive infection risk: in 2003, for instance, there was a perfectly consistent prediction by all 4 models in 9 of the 13 participating orchards. A coincidental forecast was provided by 3 of the 4 models in the other 4 orchards.

    The results indicate that any of the risk assessment models could provide an increased accuracy of the actual infection risk prediction if combined with an estimation of the incidence of Erwinia amylovora colonization in the open flowers. We found no convincing differences in the size of the epiphytic population in flowers of cultivars possessing high or low susceptibility to Erwinia amylovora.

    We conclude that the easy-to-use methods tested could be used by the fanners to recognize weather-related risks, especially when coupled with an estimation of the proportion of the pathogen-infested flowers. This local prediction would provide rapid information (faster than the regional forecast systems) specifically for a given orchard.

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