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  • Floral biology and fertility in peaches (Review article)
    9-14.
    Views:
    159

    Floral biology and fertility in peaches (Review article)

  • Evaluation of Colour Versions of Wild Sage (Salvia nemorosa L.)
    111-115.
    Views:
    188

    In the continental weather zone, more and more frequently occurring extreme conditions require continuous renewal of the market which generates constant challenge for the ornamental plant breeders. Most of the traditionally used decorative ornamental plants are sensitive to these extreme conditions. In 2001, Department of Plant Biotechnology, Debrecen University initiated an interdisciplinary breeding program in collaborations with Zoltan Kovats (he dealt with hungarian drought-tolerant plant species) to produce new or reintroduce forgotten drought-tolerant ornamental species into public parks and roadsides. From ~900 species of Salvia genus, Salvia nemorosa L. has been known as a medical plant, however, because of its high adaptation ability and decorative nature it is a highly recommended ornamental plant as well. Salvia nemorosa L. has a low maintenance, extremely droughttolerant, fast growing plant, generates proper cover, and highly competing weeds on roadsides. Nowadays, 50-60 varieties are available; however this number could be increased by new hybrids. Great morphological and colour variation could be seen within the species, from different white to deep violet. The main goal of this research is the production of elite lines with wide colour and morphological variation in wild sage. We have already obtained 25 different clones for further investigation without eliminating the original plants generating an in vitro gene bank as it has been done by Italian breeders.

  • Effects of different pollination treatments in genotypes of Prunus salicina Lindl.
    141-146.
    Views:
    119

    The low productivity in the Japanese plum (Prunus salicina Lindl) is related with self-incompatibility characteristics, so other species or varieties that act as pollinators need to be present to improve fruit production. The objective of this work was to study the efficiency of pollination in different genotypes of P. salicina using treatments of natural self-pollination, cross-pollination with P. armeniaca cv. Giada and open pollination. These treatments were evaluated through viability techniques and in vitro and in vivo germination of pollen grains; the growth of pollen tubes along the pistil was also observed. Genotypes used in this study showed differences for each one of the pollination treatments. Some genotypes showed signs of self-sterility and interincompatibility with P. armeniaca cv. Giada, while others showed partial self-fertility characteristics or pseudocompatibility. Moreover, some genotypes showed a higher affinity coefficient with cv. Giada and these will be indicating a possible intercompatibility. These studies will be an important contribution breeding and selection of intra and intercompatible genotypes to be used in commercial orchards.

  • Hungarian fruits and vegetables of high anti-oxidant activity as functional foods (Review article)
    13-21.
    Views:
    261

    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.

  • Production of transgenic carnation with antisense ACS (1-aminocyclopropane44-carboxy late synthase) gene
    104-107.
    Views:
    167

    Dianthus chinensis and Dianthus caryophyllus varieties were tested for shoot regeneration from leaf and petal explants and transformed with Agrobacterium tuniefaciens strains (EHA 105 and LBA 4404) harbouring an apple derived ACS cDNA in antisense orientation in order to reduce ethylene production and influence the ethylene dependant traits in carnation. After transformation regenerating shoots were selected on MS medium containing 50-75-100-125-150 mg/1 kanamycin and supplemented with 1 mg/1 BA, 0.2 mg/1 NAA. Transgene integration was proved by PCR analysis with npt II spcific primers followed by Southern hybridisation of DNA isolated from green shoots on medium containing 150 mg/1 kanamycin. Several putative transformants were subjected to RT-PCR in order to examine the npt 11 expression at mRNA level. Both the transformant and the non-transformant plants were potted into glasshouse to observe the effect of changed ethylene production on flowering time, petal senescence and vase life.

     

  • Evaluation of different sources of resistance for breeding powdery mildew resistant grapevine varieties
    35-40.
    Views:
    163

    The appearance of resistance to powdery mildew was investigated on seedling progenies of interspecific crossings. Hybrids of American and East-Asian wild species and one Vitis vinifera variety (Janjal kara) were used as source of resistance in the crossings. The resistance of foliage and of berries were tested in the field at the time of vintage. The degree of resistance was ranked into six classes.

    In American and Asian hybrid derivatives there were few highly resistant progenies, but in the hybrids of Janjal kara variety more than 90 % of the progenies proved to be highly resistant to powdery mildew. According to the distribution of classes of resistance in the populations the resistance of American and Asian sources are mostly influenced by additive gene affects. The resistance of Janjal kara seemed to be mono or digenic.

    No close correlation was found between the powdery mildew resistance of the foliage and that of the berries.

     

  • Evaluation of sour cherry varieties grown with environmental technology
    39-41.
    Views:
    424

    The evaluation of a produce is an important moment of predicting its success on the market. The general impression, which is decisive, when a consumer chooses to purchase the commodity, should be interpreted in more objective, measurable terms. Primary data have been collected on fresh fruits derived from different growing technologies by organoleptic tests and the data filled up in the forms are processed with correlation analysis. The components were: taste, aroma, flesh firmness. The coefficients of correlation showed that the rest of characters as the appearance, juiciness, and the sugar/acid ratio.

  • Changes in the Dry Matter and Sugar Content of Nantes Type Carrots during Storage
    67-71.
    Views:
    171

    Changes in the dry matter and sugar content occurring during the winter storage of Nantes type carrot hybrids grown on soils of different quality were studied in 199912000 and 200012001. The dry matter content of the varieties tested depended on the production site and on the weather conditions prevailing in the growing season. The increase in the dry matter content during winter storage reached 6 to 7 per cent in the crop grown in a dry year and 1.5 to 2 per cent in a rainy year. The sugar content was lower in the rainy year (1999) and on brown sand (Szatymaz) than in the rather dry year (2000) and on chernozem soil with residual forest (Tordas), respectively. The increase in sugar content (1 to 5 per cent) measured at the end of storage was related to the season's weather conditions.

  • The uses of wolfberry (Lycium barbarum L.) as a fruit in an international breadth of view
    7-13.
    Views:
    260

    Lycium barbarum is known exclusively as an ornamental plant in Hungary, and is planted so, as popular belief deem it a toxic plant. The plant’s fruit receives great respect in countries abroad, thus, due to its favourable content values the Lycium has achieved the title of ‘biological gold mine’. The last couple of years has seen the import of Lycium shrubs and its corresponding products, dried goods or in the form of various processed products which have been marketed and sold at extreme prices (under name of Goji, Wolfberry, Lifeberry). Our goal was to examine the similarities of the content values of wolfberry found in Hungary and those cultivated abroad. Along with Miklós Józsa the domestic Lycium population was surveyed based on foreign examples, between the years 2009 and 2011. Those defined sweet and largefruited were selected for further investigations to be set into a clone repository. This clone repository– which contains 67 different clones from a number of regions of Hungary – was established in the nursery of Dr. Miklós Józsa, located in the city of Szombathely. The phenological and morphological characteristics and the fruit ripening and quality indicators of plants in the clone repository were investigated. Six ‘best’ clones – selected based on flavour, disease-resistance and vegetative characteristics (plant size, fruit set, yield and fruit size) were analysed based on their content values. The control plant was a cultivar imported by a delivery service, found also in growing. In addition to the results of the selection, the results of the content values of the six selected ‘best’ clones (total soluble sugar content, glucose-fructose ratio, carotene content, FRAP value) is documented in this paper. Further, based on the resulting information the possibilities of the fruit’s utilization are suggested. Significant differences were measured in the vegetative characteristics of the clones (plant size, fruit set, yield and fruit size) and of those of
    its inner content values. The resulting properties are considerable in regards of the plant’s introduction into cultivation and also utilization. Based on growing characteristics, more favourable clones were selected than the foreign varieties already in growing. Those clones selected by us have had similar or better content values than foreign breeds. The investigation of these content values is still in progress.

  • Climatic indicator analysis of blooming time for sour cherries
    11-16.
    Views:
    177

    County Szabolcs-Szatmár-Bereg produces more than the half of the total sour cherry grown in Hungary. Successful production, i.e. yield, depends largely on weather conditions. Most attention should be paid to the weather during the blooming period, being most decisive from the points of view of quality as well as quantity. In order to predict yields expected, the characterisation of the most important weather parameters is necessary. For that purpose, the database of the Institute of Research and Extension Service for Fruit Growing at Újfehértó Ltd. has been utilised. Records of weather conditions were collected throughout the period 1984-2005, i.e. daily minimum, maximum and mean temperatures (°C), precipitation (mm), and phonological diary of sour cherry varieties ’Újfehértói fürtös’, ’Kántorjánosi’ and ’Debreceni bôtermô’. Data of 7 indicators have been traced: number of frosty days, the absolute minimum temperatures, means of minimum temperatures, number of days when daily means were above 10°C, means of maximum temperatures, number of days without precipitation, and number of days when precipitation was more than 5 mm. On the one hand, we surveyed the changes; on the other hand, estimates have been attempted for the future changes expected during the following decades. The indicators being associated with certain risky events may serve for the prediction of the future recommendations to prevent damages.

  • Comparative investigations on protoplast culture of some Brazilian and Hungarian sweet pepper cultivars and hybrids
    39-45.
    Views:
    177

    Cotyledon protoplasts were isolated from 16-18-day-old in vitro grown seedlings of 9 Brazilian and 3 Hungarian pepper varieties and hybrids. Large numbers (average 9.59 X 106 protoplasts g 14 fresh weight) of highly viable (average 87.0%) protoplasts were released using a pectocellulolytic enzyme mixture. Protoplasts were cultured in K8p mediuni using an alginate disc embedding method. The osmotic pressure of the medium surrounding the alginate-embedded protoplasts was reduced by replenishing the liquid medium at K8p:K8 ratios of 1:0. 2:1, 1:1 in the first. second, and third week, respectively. Initial plating efficiency (IPE) average was 38.5% and after 21 days protoplasts reached microcolonies (15-20 cells) stages. Microcolonies were transferred after 3-4 weeks to a MS-based medium supplemented with 1.0 mg I-1 zeatin, 3.0% (w/v) sucrose, 0.24% (w/v) phytagel and pH 5.8, whereupon they formed callus. Final plating efficiency (FPE) average was 0.29% at a plating density of 1.0 x 105 protoplasts Protoplast-derived calli were cultured on a range of MS-based media supplemented with either BAP, IAA, TDZ; and zeatin. No morphogenic response was observed in any genotype investigated.

     

  • Transmethylation and the general defense reaction of plants
    35-40.
    Views:
    165

    Plant breeding for resistance, namely building specific resistance genes into cultivated plants to ensure resistance against certain pathogen species, is a several-decade-long practice. While looking for purposes of failures appearing during the cultivation of varieties created in this way, a plant feature that ensures non-specific reactions against effects which evoke biotic stress attracted our attention. We named this plant defense form the general defense reaction. The general defense reaction is a fundamental attribute of the plant kingdom, fulfils the role of plant immune system and manifests itself in cell enlargement and cell division. Plants with a high level general defense reaction endure abiotic stresses as well.

    In studying the biochemical background of the interaction of the general defense reaction and transmethylation, we found that transmethylation has important role in warding off both biotic and abiotic stresses. According to our observations, plants possessing high level general defense system are suitable for thorough examination of the process and plant physiological role of transmethylation. Biochemical studies also strengthened our observation, which has been taken on the basis of phenotype, that the general defense system can not be ignored during future plant breeding.

  • Examination of valuable ingredients of some wild fruits
    71-74.
    Views:
    153

    A possible way of the development of Hungarian agriculture is the selection and growing of new fruit species and varieties featuring special qualities, with high biological nutritive and health protecting properties due to their natural composition. A reserve for such new fruits is the native dendroflora, e.g. those wild-growing trees and shrubs of Hungary, which bear edible fruits. The publication is giving a summary of chemical analyses done on the fruits of the plants listed below. The research team on the project started the work in 2001 with

    woody species (genera) as follows:

    • common elder (Sambucus nigra) clone named Szcs-1, Szcs-2, Szcs-3, Szcs-4, Szcs-5, SzcsK-1, SzcsK-2
    • dog rose (Rosa canina) types: clones named Sz-1, Sz-2, Sz-3, Sz-4 and Sz-5 .
    • native rowans: Sorbus dacica, S.rotundifolia, S. degenu, S.bakonyensis cv. Fánivölgy
    • hawthorns: Crataegus monogyna, C. orientalis,C..v lavallei.
    • cornel cherry: Cornus mas cv. Császló.

    The present paper is reporting on the content of the following compounds in the fruits: dry matter (refractometric values), total acid content, ascorbic acid, 13-carotene, pectin, minerals and carbohydrates. The results have shown that these wild fruits have excellent composition. Besides their curative effects, their content of minerals, ascorbic acid and 13-carotene has surpassed that of the traditional fruits. These fruits are rich in ascorbic acid, 13-carotene and pectin. The high content of the above-listed, biologically active compounds makes the new wild fruits studied suitable for the preparation (and later: mass-production) of special curative and exclusive products.

  • Effect of hail protecting nets on the quality of apples
    77-80.
    Views:
    237

    Today, successful fruit growing depends largely on the security of production. Among the technological elements of a secure growing system, the use of hail protection nets serves special attention. Components of security are the regularity, conspicuous large yields with excellent quality, which determine the prices and profitability as well (Szabó et al., 2010). In the European Union, most of the apple growing countries produce higher yields by 10-20% than Hungary. The conditions of better yields are partly due to a more favourable ecological milieu, partly to more developed technologies and serious discipline of the operations. Our own competitiveness could be developed first of all in those moments. As a consequence of global climatic changes, excesses of weather, i.e. hail-storms became more frequent. Different methods of protection against hail are developed abroad but also in Hungary. The examination of effects of the hail protection nets compared with the check without nets has been the purpose of our experiments. The growing system was the intensive one with high planting densities. Fruits of the two subsequent years have been compared as grown with and without hail protective nets. It turned out that in one season when shoot growth was stimulated, the shadowing effect of the net increased in addition the growth and at the same time braked the differentiation of flower buds, which exerted negative effects on yield of the next year. Let alone this phenomenon, the quality of fruits was not influenced by the hail protection net.

  • Variety specific integrated fruit production development in order to optimize inner content values
    27-31.
    Views:
    169

    In this paper we introduce our results of three years (2007-2009) investigatio ns carried out in the framework of "Research and development in foodstaff chain" - project of Regional University Knowledge Center by the members of Corvi nus U niversity of Budapest - Department of Pomology and. Research Institute for Fru it growing and Ornamentals.  Budapest-Erd. The main objectives of the project were the followings: submi ssion of sour cherry candidate suitable for industrial process for state approval; determination of physica l parameter and inner content value changes of sour cherry varieties duri ng ripening; evaluation of health care attributes of sour cherry fruit; ripen ing process description by the colour and the force required to pick fruits of sour cherry. We stated that the optimal begi nning and period of the harvest can be determined wi th the fruit removal force. In this period the fruit growth stops. ju iciness rat io does not change. refractions are approximately equal.acidic content turns to decreasing trend.However the proportion of anthocyan in and polypheno l can still increase. Fruits harvested in this period fulfil a wide range of industrial process opportunities. 'Erdi jubileum ·and candidate IV-3/48 according to their inner content values arc suitable for high quality products (containing real fruit material in high proportion).

  • Biotechnologies for ornamental plants: some insights to the Brazilian productive chain
    51-59.
    Views:
    251

    The world industry of ornamental plants is under wide transformations regarding the changes in the cultivation, management, post­harvest technologies and the use of new (bio)technologies to assist the improvement and development of new varieties. This industry worth more than US$ 20 billion, but Brazil shares only 1% of this value. To compete at this market with permanent technological innovation, the country needs to be tuned in with the progresses in the biotechnologies applied to the productive chain of ornamental plants. In this revision, we analyze the Brazilian and world ornamental market emphasizing the role of the biotechnologies in the modernization and increase of the competitiveness of the sector.

  • Comparative study of plum cultivars belonging to different taxons during 1980-1996
    13-19.
    Views:
    142

    The program of the Research Institute of Cegléd, comprises the acclimation and selection of 7 Prunus-species and 39 cultivars grafted on Myrobalan C. 679 (P. cerasifera) seedling stocks. In addition two varieties have been investigated on three different rootstocks each: Myrobalan C. 174 (P. cerasifera), Bitter almond C. 449 (P. arnygdalus var. amara) and Sweet almond C. 471 (P. amygdalus var. dulcis). Fruits of commercial quality are produced maroly on some cultivars of P. salicina-, P. italica- and P. cerasifera character. Authors explain the three possible causes of low yields experienced in non-European plums:

    1/ unfavorable environmental conditions

    2/ lack of irrigation and

    3/ superficial information concerning the variety, rootstock and adequate traditions as well as growing practices.

    A rather tight correlation has been stated between blooming dates and the main ripening period. However, the early blooming time alone cannot be considered as the cause of low productivity. The decay of plum trees is attributed to special ecological requirements and phytosanitary problems of the foreign plum cultivars. The analysis of regression revealed stochastic relations involving several other characters too, which facilitate the planning of cross-combinations in the breeding program.

  • The use of SSR markers in family Rosaceae
    29-32.
    Views:
    120

    The identification of plant species and study of their genetic relatedness is an important object of plant genetics. The Rosaceae family contains a lot of economically important fruit, ornamental, and wild plant species. The microsatellite markers have been proven to be an efficient tool for description of the genetic relatedness among varieties and species. Their evolutionary conserved regions enable them to differentiate among various accessions. This article intends to show proceeded identification and characterization projects on Rosaceae species by using SSR markers. The article presents sources of already published primer sequences. The use of already published primers can highly reduce the cost and duration of this kind of researches.

  • Growth and yield of sweet cherry trees on different roostocks
    98-101.
    Views:
    225

    The first nine years' results of sweet cherry rootstock trial from Hungary are presented with the aim to select efficient rootstocks for the local ecological conditions. The trials were established in 1989 with 'Van' and 'Germersdorfi óriás' cultivars on the following rootstocks: mahaleb Sainte Lucie 64, Colt, MxM 14, MxM 97. All the trees were headed at 80 cm and trained to a modified Brunner-spindle system. Tree size and yield was measured every year, and the cumulative yield efficiency was calculated.

    Based upon the results, mahaleb cherry SL 64 is a vigorous rootstock with good compatibility and productivity. In comparison to SL 64. the trunk cross-sectional area and canopy spread of the 'Van' trees decreased by 10-15% on rootstock Colt, while the trees of 'Germersdorfi orias' on Colt roostock grew even larger than on SL 64. Considerable 30-40 % reduction of tree size was achieved on trees grafted on M x M hybrids. Trees of `Germersdorfi óriás' showed a similar tendency without significant differences. The cumulative yield efficiency of `Van' trees after nine years was highest on rootstock MxM 14, followed by Sainte Lucie 64. Trees on Colt and MxM 97 rootstocks showed low productivity. `Germersdorfi óriás' produced the highest cumulative yield efficiency on SL 64, followed by MxM 14 and Colt and last MxM 97. Biennial bearing index of heavy cropping 'Van' trees was smaller than that of `Germersdorfi óriás'. The trees of 'Van' on MxM 97 showed higher biennial bearing index, while 'Germersdorfi orias' on different rootstocks showed similar tendency, but without significant differences.

    MxM 14 and MxM 97 rootstocks reduced the crotch angle of the shoots on both sweet cherry varieties which is disadvantegous to spindle training. Slight suckering (1-3/year) of the rootstocks Colt, MxM 14 and MxM 97 were observed during the first few years.

  • Generative propagation of Robinia x ambigua POIR. – Pink locust
    41-42.
    Views:
    245

    The genus Robinia is a small group of about 10 species of trees and shrubs indigenous only to NorthAmerica. Two species are endemic to Mexico, one being confined to south-western part of the country, while the rest are endemic to the south-eastern part of USA. Of the most important species and varieties of genus Robinia, Robinia x ambigua Poir.(Robinia viscosa x R. pseudo-acacia)-pink locust can be considered as the most significant one for bee-forage and decorative planting. In this paper a generative propagation method is presented for pink locust.

  • Sunburn incidence of apples is affected by rootstocks and fruit position within the canopy but not by fruit position on the cluster
    45-51.
    Views:
    221

    Authors investigated sunburn incidence of apples on the combinations of three different growth inducing rootstocks (M.9,MM.106 and seedling) and five varieties (‘Smoothee’, ‘Golden Reinders’, ‘Granny Smith’, ‘Gloster’ and ‘Jonagold Jonica’). Symptoms were classified as sunburn browning, sunburn necrosis and photooxidative sunburn. The frequency of symptoms was recorded at various parts of the canopy (N, E,W, S, and lower canopy, upper canopy) and on the cluster (terminal, lateral). Cultivar susceptibility varied between 0.30 and 5.65% on M.9 rootstock, ‘Granny Smith’ seemed to be the most susceptible cultivar whereas relatively low percentage of damaged fruit was observed for ‘Gloster’. On MM.106 and seedling rootstocks, damage level was significantly lower than on M.9. Remarkable differences were not observed in the share of the three sunburn types between cultivars. The most common symptom observed was sunburn browning. Far less fruit was affected by sunburn necrosis and photooxidative sunburn. Photooxidative sunburn symptoms were not found on ‘Granny Smith’ and ‘Gloster’ fruits on MM.106 rootstock. Latter cultivar did not show sunburn necrosis symptoms either. With increasing growing vigor of the rootstocks the share of sunburn browning increased. Fruits with sunburn symptoms were found in a great majority on theW quadrant of the trees. This was true for all cultivars. Remarkable differences in the location within the canopy of affected fruits between the three types of sunburn were not observed. Specific distribution of sunburned fruit was observed along the vertical axis of the canopy, too. Most of the damaged fruit were found in the upper canopy. This is particularly true for trees on vigorous stocks such as MM.106 and seedling. On M.9 rootstock, depending on cultivars 5.9 to 38.9% of sunburned fruit was located in the lower canopy. Most common symptom in the lower canopy was the sunburn browning, however symptoms of sunburn necrosis were not found at lower canopy level. Low rate of photooxidative sunburn was observed such lower canopy conditions. Sunburn incidence was very similar on king or side fruit. Significant differences were not found in the share of each sunburn types between fruit positions on the cluster. This was not influenced by rootstocks either.

  • Hungaricum as a quality of fruits and fruit products
    71-81.
    Views:
    183

    The territory of the Hungarian state is largely suitable for the purpose of growing fruits of the temperate zone species. During the next decennia, the annual volume of Hungarian fruit production is expected to be around 1.1-1.3 million tons, from which some 15% is considered to be a produce of Hungary or "Hungaricum" (90 thousand tons of sour cherry, 50 thousand tons of apricot, 20 thousand tons of raspberry, 10 thousand tons of walnut). These fruits symbolise the country's special quality, which are worth to catch the interest the foreign consumers.

    The category of Hungaricum involves almost exclusively varieties of Hungarian origin as sour cherries, apricots, raspberries and walnuts, and they are representing outstanding qualities on the international markets.

    As for the fruit products the fruit brandies are eligible to be "Hungaricum" and are called exclusively "Pálinka". The Pálinka, provided to be distinguished with a geographic mark and will be competitive on the world market. Smaller quantities, though significant produce is represented by the deep frozen raspberry.

  • Grape variety comparison of different stress tolerance based on the quantitative measurement of carbohydrates
    37-40.
    Views:
    156

    The analyses of various host-pathogen relationships have established the response reaction roles of carbohydrates — especially monosaccharides — measurable in the vegetal parts of the host. Published results also provide information concerning the way various pathogens utilize carbohydrates and concerning the carbohydrates pathogens prefer out of the "selection" provided by the host plant. The role of carbohydrates in the response reactions to abiotic stress has been studied on several plant species as well — currently, too, it is an often discussed area of research. The above-mentioned results form the basis of our intention to study the connection between susceptibility to grey mould and the quantity of measurable carbohydrates in the leaves of grape varieties of various stress tolerance levels.

  • Effect of intensity of bee visitation and the foraging behaviour of honeybees on the fruit set and yield of apple (Malus domestica Borkh.)
    31-39.
    Views:
    134

    Based on the results of our experiments, both the relative and the effective intensity of bee visitation were rather different depending on the cultivars as well as the time of the day. While it varied between relatively extreme values (40-80%) in the morning for the varieties examined, there were much smaller differences between the intensity of bee visitation at the afternoon, because the relative bee visitation attained 70-90% at each cultivar. These results showed that the differences arising from intensity of bee visitation of different cultivars should be taken into consideration more carefully in the morning in orchard planning and in estimating the number of honeybee colonies required.

    The results showed that the greatest percentage of fruit set and the highest number of viable seeds per fruit were measured on branches of those cultivars that were most frequently visited by pure pollen gatherer bees as well as by bees collecting both nectar and pollen (mixed behaviour). The effect of pure pollen gatherers and of bees with mixed behaviour was highly significant from the statistical point of view on the fruit set and the number of viable seeds per fruit.

    Those bees that were sucking nectar only from apple flowers did not proved to be effective pollinators at all. Relationship between their number and the fruit set as well as the number of viable seed per fruit were not significant because the coefficient of correlation was close to nil.

    The ratio of side worker nectar gatherers was negatively correlated with the fruit set and the seed content of fruits of apple cultivars examined at both of our experimental sites, at Mosonmagyaróvár and Feketeerdő as well. The presence of side worker nectar gatherers resulted in higher decrease of fruit set and seed content of fruits at Feketeerd6 than at Mosonmagyaróvár, especially in the morning.

    The effect of flower visiting intensity by other pollinating insects was found to be fairly variable according to the time of the day. In the morning they had no effect on the fruit set as well as on the seed content of fruits either at Mosonmagyaróvár or at Feketeerdo. However, at the afternoon, when their intensity was greater, the correlation was a bit stronger.

  • Salt tolerance of sweet pepper seedlings
    62-66.
    Views:
    131

    Laboratory germination tests have been made with three white fruit pepper varieties and with one spice pepper in filter paper rolls wetted with KCl solutions of different concentration. Parallel tests have been conducted with the other species (lettuce, tomato, kohlrabi) to compare the salt tolerance of paprika with that of other vegetable crops.

    In greenhouse, the action of KCl has been investigated with transplants raised in soil mixture, in rockwool and with seedlings transplanted from rockwool into soil mixture. Like the trials in the laboratory, the experiments in soil mixture have been made with other plant species, too.