Agroclimatological properties of growing sites assigned to apple and pear production in Hungary

Apple and pear growing sites in Hungary are classified into four regions according to the Hydro-thermic Coefficient: dry, moderately dry. moderately humid and humid. Most of the plantations of apple and pear are located in regions considered as moderately dry and moderately humid. Within that category, the two respective species have different preferences, i.e. the ecological features of Hungary give different opportunities for apple and pear growing. Apple is grown almost everywhere in the country, successfully. The selection of cultivar-regions is needed mainly for increasing competitiveness on the market. Main apple growing regions are listed in 3 large groups. For the definition of cultivar-regions, mainly the configurations of soil and precipitation, i.e. conditions of the soil and opportunities of gaining water were decisive. Market factors are also considered. The area assigned to pear is much less than that of apple, in Hungary. Some well known and popular varieties would require high air humidity which cannot be presented in most of Hungary. Therefore, the possibility to establish regions for pear varieties is restricted, we have to create a particular micro-environment. Two groups are potential. The first one comprises sites where the annual precipitation is 700 mm, at least. There, apple and pear production would compete each other. In more dry habitats (less than 700 mm annual precipitation), micro-environments should be found and only drought-resistant, mainly summer-ripe cultivars should be chosen with, preferably, low tendency of sclereid formation. In that case, neither irrigation could help to produce adequate quality in varieties sensitive to low air humidity.


Effect of N, P, K and Mg fertilizers on some vegetative and generative parameters of a sweet cherry cultivar

This two-year-study was aimed to provide results on the effect of nitrogen, phosphorus, potassium and magnesium fertilizer treatments (control, NP, NPK, NPKMg) on vegetative and generative features of the sweet cherry cultivar ‘Carmen’. Examinations were performed in an orchard planted in 2012 on Prunus mahaleb rootstock with spacing of 5 x 2.5 m. All treatments improved the vegetative features of the sweet cherry trees in both years of 2016 and 2017. Fertilizer treated trees increased trunk cross section area (TCSA) with 51.3-63.1%, while control trees showed 48.3% trunk growth increase. Yields of control trees were lower in both years (5.9-7.2 kg/tree), than that of the fertilized trees (7.8-11.3 kg/tree). Treatments also increased the phosphorus (16-22%), magnesium (12-20%) and potassium content (3.5-18%) of the fruits compared to control treatments.

Cost-effective plantlet production and wintering method of virginia fanpetals (Sida hermaphrodita L. Rusby)

The main goal of this research was to work out programmable, cost-effective and industrial scale technologies of mass propagation from the seeds of rootstock nurseries of undomesticated American populations of Sidahermaphrodita. During our previou`s seed treatment experiments, it was concluded that around 60% of the Virginia fanpetalsseeds collected during the four cropyears can be considered as high quality, infection-free, normally imbibing and germinating seeds (Kurucz et al., 2013a,b). The experiments performed with the nurse-in-tray method developed by us showed that the summer-autumn nurse-in-tray plantlet production and unprotected wintering of Virginia fanpetals with properly pre-treated and fractioned seeds is a promising new method. No weeds appear between the plants, but only on the side of the cases during plantlet production. The investment cost of the method is minimal. There are no heating costs and this phytotechnique can be easily and properly mechanised. Plantlet production can be performed near the large-scale plots. After exploring the root and shoot system, it was concluded that the nurse-in-tray method is suitable for producing plantlets with hardened and strong roots. Scheduled plantlets can be produced in an industrial scale volume by the time of early spring (March) plantlet planting. The excavateof plantlets can be flexibly adjusted to the needs; they may even grow in the plantlet cases for a whole year. We think that these innovative plantlet production and wintering methods which are suitable for large-scale use will make Virginia fanpetals a proper feedstock for the constant supply of the Biomass Supply Chain both in Hungary and in European countries which are in the same climate zone. The comparative analysis of the costs of this procedure calls for further research.

Cooling irrigation as a powerful method for microclimate modification in apple plantation

Irrigation in some countries is a horticultural practice mainly used only to supply water. At the same time the use of microsprinklers have a powerful influence on the changes of temperature in orchards. When the air’s temperature is high (about 20 °C or higher) the evaporative cooling irrigation significantly decreases the plants’ surface temperature and air temperature. The cooling effect is stronger when the air is dryer. By using cooling irrigation regularly, canopy temperature can be decreased so that the beginning of blooming can be delayed. Also if the blooming is early and frost probability is high, serious damages can happen in orchards. The beneficial effect of cooling irrigation is the temperature reduction and frost protection. InMarch 2010, one month earlier than the expected blooming an irrigation system was established to produce anti-frost treatment and regulate the micro-climate of a Gala apple orchard which belongs to the University of Debrecen (Hungary). The objective of sprinklers was to cool the air by increasing water evaporation and relative humidity. The position of the micro-sprinklers was planned in three levels (around the tree trunks, a few cm near to the soil surface, in the crown region and above the crown, a half meter higher). The results showed that the water sprayed in the orchard by micro-jets influenced decisively the temperature of the plantation. At higher temperatures (around 20 °C), the drop of temperature may attain 5–7 °C. A low relative humidity of the air may increase the relative effect. When water was applied at intervals of 15 minutes for ten times a day from 8 am to 18 pm, the air, flowers and bud’s surface temperature could be kept low.At certain days when the temperature was higher than 10 °C, irrigation was used at night time in similar 15 minutes intervals, from 18 pm and 6 am. The beginning of bloom could be delayed for more than ten days. The Gala apple variety blooming dynamics was characterized by a logistic curve in the treated as well as in the control plot. In the treated plot, the curve was steeper than in the control one in spite of the equal temperatures measured in the plots. Under Hungarian climatic conditions, the method was successfully used to delay blooming dates. The main result was the diminution of the frost damage in the spring that assured apple yields.

Comparison of varying pollen source on productivity of sour cherry (Prunus cerasus L.) cultivars

Fruit set of five sour cherry cultivars (‘Újfehértói fürtös’, ‘Éva’, ‘Petri’, ‘Pándy 279‘ and ‘Csengôdi’) of eight years-old trees grown in Újfehértó, located in the Eastern north part of Hungary have been studied over two years (2008 & 2009). Following reciprocally cross-pollination, free-pollination, self-pollination (autogamy) artificial self-pollination (geitonogamy) were studied. The results show that both maternal and paternal parent cultivates had significant effects on the percentage fruit set. Significant differences have been found in fruit set among years and among pollination treatments. Fruit set of free-pollinated Pándy 276 cultivar was low and seasonally highly variable. The yield of this cultivar on self-pollinated flowers was nearly 0%, and in this treatment the maximum yields did not reach 10% in any of the examined cultivars. There was no significant relationship in the fruit set of free-pollination and natural self-pollination treatments.

The investigation of suitability to various purposes of industrial processing in stone fruit varieties and variety candidates

In the laboratory of Conserve-technology in the Research Institute for Fruit Growing, Company of Public Utility, Cegléd, 6 sour cherry, 6 apricot, 5 peach and nectarine, 6 plum and 4 Japanese plum varieties (canned fruit, juice, dried fruit, deep frozen). The products were evaluated by organoleptic methods on a scale of 1-5 steps. The varieties receiving at least 4 points were listed (in brackets also the respective product was indicated): `Kántorjánosi' sour cherry (for all the three purposes), '13' variety candidate (canned and deep frozen), 'T' var. cand., (canned, deep frozen), 'Érdi bőtermő' (dried fruit), 'R' var. cand. (deep frozen); ‘Ceglédi arany', 'Ceglédi bíborkajszi', 'Magyar kajszi"C. 235' (fibrous juice); `Babygold 5', 'Redhaven' peaches, and 'Caldesi 2000' nectarine (canned); 'Stanley' plum (canned), 'Besztercei Bt, 2' (deep frozen).

Flower visiting activity of honeybees on fruit species blooming subsequently

In the small demonstration orchard of the College Faculty of Horticulture at Kecskemét the blooming time, the flower density and the honeybee activity was observed at a number of cultivars of 20 flower species during four consecutive years.

Fruit crop species were in flower during 3-4 months altogether. The blooming period of them was classified into five groups as early (almond, apricot, gooseberry), middle early (sweet cherry, red currant, currant-gooseberry, black currant, white currant, peach, plum, sour cherry), middle late (pear, strawberry, apple), late (black elder, quince, medlar, raspberry, blackberry-raspberry) and very late blooming period (blackberry). The blooming period of the members of the groups of early and medium early blooming often coincided partly and the same happened between the medium and the medium late as well as between fruits of late and very late flowering.

The flower density of some fruit species is extremely variable (currant-gooseberry, medlar), while at others it is fairly stable and evenly dense in consecutive years (sour cherry, sweet cherry, strawberry). At other fruit species it is moderately changeable. Some fruit species tended to attract more honeybees than others (plum, apple, quince, medlar) and some of them tended to attract much less (black elder, pear) but most species can be regarded as of medium attractivity.

On the flowers of some fruit species (pear, strawberry, quince) honeybees gathered pollen predominantly. At most fruit species however pollen and nectar gathering behaviour seemed to be gradually changing during the season. Namely most honeybees tended to gather pollen at the flowers of the early blooming fruit species, but on the other hand typical foraging behaviour gradually shifted to nectar gathering at the flowers of fruit species of moderate and late blooming periods.


Organic versus integrated apple growing: I. differences in soil and leaf parameters

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 hydroponic and peat-free media in transplant production of Rudbeckia hirta varieties under different photoperiodic lighting and their photosynthetic parameters

The purpose of this research was to determine the effects of varieties, different light conditions (short day, long day, natural short day with light pollution), and different growing media (perlite, peat-free, peat-based, aeroponics system) on Rudbeckia hirta plant production under controlled conditions (greenhouse). The morphological effects of each treatment (photoperiodic lightings and media) on different Rudbeckia varieties determined at 11 weeks-old ’Napfény’, ’Toto Gold’, ’Autumn Colors’, ’Prairie Sun’ and 16 weeks-old ’Napfény’. Plantlets received 12 hours daylight did not initiate flowers, remained stage of the leaf rosette in case of all varieties. The 14 hours light treatment in the aeroponics system and the same treatment in perlite and control (natural short day with 14 hours light pollution) plantlets had developed inflorescences or flower buds. The inflorescence axis of ‘Napfény’ was appeared at 13 weeks under long-day conditions, with 1.7 (perlite) - 2.7 (aeroponics) flower buds in 16 weeks. ’Toto Gold’, ’Autumn Colors’, ’Prairie Sun’ varieties developed inflorescences at 8 weeks, 14 hours aeroponics system resulted in the most of flower buds (’Toto Gold’: 6.5, ’Autumn Colors’: 3.25,’Prairie Sun’: 4.8 flower buds) at 11 weeks. Long daylight manipulation could be minimized crop times and achieved flowering potted plants at 11 weeks. The peat-based and peat-free media effect was observed on ‘Autumn Colors’. The number of leaves of peat-free ‘Autumn Colors’ transplants (16.8-20.3) was significantly higher than peat-based media (13.5-15.5). Other morphological parameters were not affected by the media treatments.

A preliminary study on some features of two new resistant apple cultivars in a multi-row planting system

The aim of this work was to report preliminary results on some features of two new resistant apple cultivars (cvs. ‘Galiwa’ and ‘Story Inored’) in multi-row system in the early bearing years of the orchard. Trees were planted in spring of 2015 in double row design (3.5 m+1.4 m x 1.0 m) with planting density of 5357 tree/ha. According to our results cv. ‘Story Inored’ presented more vigorous growth, than cv. ‘Galiwa’. Trees of cv. ‘Story Inored’ reached 2.7 m in the third year, but cv. ‘Galiwa’ could reach only 1.95 meter. Due to late spring frost 100% yield loss was observed in the second year. In 2017 cv. ‘Galiwa’ produced 5.3 kg/tree (25 fruit/tree), while cv. ‘Story Inored’ presented 7.7 kg/tree (50 fruit/tree). Average yield was 28.4 t/ha for cv. ‘Galiwa’, as ‘Story Inored’ reached 41.3 t/ha in the third year. Cultivar ‘Galiwa’ reached the required fruit size (79.1 mm), but its coloration was weaker (43% fruit surface color). Cultivar ‘Story Inored’ can be described with smaller fruit size (69 mm) and higher percentage of surface color (93%).

Jerusalem artichoke (Helianthus tuberosus L.): A review of in vivo and in vitro propagation

Jerusalem artichoke (Helianthus tuberosus L.) is an old tuber crop with a recently renewed interest in multipurpose improvement. It is a perennial tuberous plant rich in inulin and is a potential energy crop. During food shortages in times of war Jerusalem artichoke received more attention by scientists and farmers because of its multiple uses as a vegetable, medicinal plant, forage plant and source for biofuel. The energy crisis of the 1970s motivated research on Jerusalem artichoke for biofuel as the aboveground plant biomass and the tubers can be used for this purpose. There are different methods to propagate Jerusalem artichoke using tubers, rhizomes, slips (transplants derived from sprouted tubers), stem cuttings, seeds and tissue culture. So, this review was presented to highlight on propagation of Jerusalem artichoke via in vivo and in vitro techniques.

Relations of phenometrical indices of apple fruits with weather variation in the assortment of varieties of an apple gene bank

The purpose of phenometry is to examine the measurable parameters of the plants in order to follow up the consequences of weather processes. We should fi nd the reasons, why the diameter of fruits grows larger in one season and smaller in the next. Variation may occur as a response to insuffi cient provision of water or nutrients, but also because of pathological effects and of extremely high or low temperatures, moreover, of extraordinary heavy fruit load. There are phenometrical characteristics, which consider the fi nal consequences (density of fl owers, fruits set, drop of fruits), whereas other parameters could be followed up (size, length and width of fruits) as the dynamic components of growth. The quantitative parameters of growth are functionally related to each other, where the weather conditions, soil humidity and nutrients are on the input side, thus it is possible to model the growth of fruits as a function of the environment. Initially, the relations between the main weather variables and the phenometrical data have to be cleared. In the present study, the interactions between the mentioned phenomena are presented and numerically defi ned.

Monitoring of water regime in an apple orchard

Our investigation was carried out at an micro-irrigated intensive apple orchard in Debrecen-Pallag in 2010. The aims of the study were to monitor the effect of a compacted layer on soil water regime by tensiometers and supporting the water management of the orchard. The results suggest that the physical characteristic of the examined soil is sandy soil with low capillarity and total available water content. The soil water tensions were varied between pF 0 and 2.5 due to the extreme precipitation circumstances in 2010. Tensiometers in 40 cm depth resulted fast (few hours) and significant respond to precipitation than in the 70 cm soil layer. Based on daily measurements, the soils possess a daily fluctuation of soil moisture, however the changes become more moderate in deeper layers. In accordance with all of the results, the amount of drainable water regime was about 20.6 V/V% at 40 cm depth and 18.6 V/V% at 70 cm mainly. The harmful surplus water can be infiltrated by loosening of the compacted soil layer in 50–70 cm depth or led off by vertical drainage.

Connection of fertilization conditions of sour cherry and meteorological parameters

Our analyses showed that the degree of free fertilization is mostly influenced by maximum temperature and sunshine duration.We found that free fertilization ratio increases with higher daily maximum temperatures; similar results characterise sunshine duration as well, namely we observed higher free fertilization ratio at higher sunshine duration values. Total amount of precipitation during the period between blossoming and maturity and the difference between the average daytime and night temperatures have an important role in the tendency of maturity time. Photosynthesis and respiration are essentially significant in the development of biological systems. These two processes are mostly regulated by the daytime and night temperatures. Therefore, it is not surprising that if the difference between daytime and night temperatures is large, it means intensive photosynthesis and a low degree of respiratory loss. Under these conditions intensive development and ripening can take place; however, in case of a low temperature difference intensive respiration slows down the process of development. Duration of ripening is also significantly influenced by the amount of precipitation of the period between blossoming and maturity.Abundant precipitation slows down the process of ripening, while dry weather accelerates it. Self-fertilization takes place in a space isolated from the environment. In spite of that, we found that effectiveness of self-pollination significantly depends on the meteorological conditions. Degree of self-fertilization is influenced directly by temperature and indirectly by other climatic parameters. We found a significant connection between the values of maximum and minimum temperatures during blossoming and the ratio of self-fertilization. Increase of maximum temperature reduces the effectiveness of self-pollination.A 1 °C increase of maximum temperature reduces self-fertilization ratio by 0,6%. In the case of minimum temperature we can state that the morning minimum temperature of 7,5–8,5°C is the most favourable. If minimum temperatures are under 4 °C or above 12 °C, self-fertilization ratio reduces to the quarter of the value characteristic at 8 °C. We believe that the effectiveness of self-fertilization can be improved considerably by the rational placement of isolator bags within the crown area, avoiding their placement to the external, western crown surface.

Hungaricum as a quality of fruits and fruit products

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.

Micropropagation of Rudbeckia hirta L. from seedling explants

We conducted experiments for developing an in vitro micropropagation protocol starting from meristems of Rudbeckia hirta L seedlings. We pre-soaked the seeds in sterile ion-exchanged water for 17 hours, and then achieved surface disinfection in two separate steps. First, we used concentrated household sodium-hypochloride solution for 20 minutes and, also for 20 minutes, we applied hydrogen peroxide of 10%, which was followed by washing with sterile ion-exchanged water three times. For the propagation of seedling meristems, the combination of half-strenght solid Murashige and Skoog (1962) culture medium containing 10 mg/1 of kinetin or 2 mg/I of kinetin + 0.1 mg/1 of 2iP proved to be the most suitable. The average number of shoot-buds developed from the seedling axillary meristem in the best culture media varied between 5 and 17. Without separating them, we inoculated the shoot-bud clusters on MS culture medium containing 2 mg/1 of IAA. After four weeks of incubation we obtained elongated shoots which we separated and inoculated into a new culture medium and we obtained elongated roots. The rooted plants were gradually acclimatised in the cultivation room, potted and carried to a greenhouse, and then planted in open field for subsequent observation. By adopting this method, our laboratory started the micropropagation of the superior and/or elite genotypes of the Rudbeckia hirta L. being of special value in respect of breeding.

Comparative analysis of Hungarian Matricaria recutita (L.) Rausch. populations

Matricaria recutita L. is a traditional medicinal plant in Hungary and its drug is known as „Hungaricum", world-wide. Plant samples and seeds were collected from 12 different habitats of three significant geographical regions of Hungary in 2001. Morphological, production biological and chemical properties of samples were examined. In relation to the morphological characteristics, a negative correlation (r= -0.75) could be observed between the average height of the plants (height of flowering shoots) and the pH value of the soil. According to the composition of the essential oil, the populations accumulating typically chamasulene (10-20%), a-bisabolol (30-50%) or bisabolol-oxid (30-50%) could be completely distinguished. Concerning the flavonoid composition the quantity of apigenin-7-glucoside was outstanding in the populations originating from the Great Hungarian Plain, it has reached the concentration of 1.8-2.8 mg/g, while the samples collected in Transdanubia could be characterised by much lower level of apigenin-7-glucoside (around 1.5 mg/g).

Blooming phenology and fertility of sour cherry cultivars selected in Hungary

Experiments were conducted during the period between 1972 and 2002 at three sites in Hungary. At Érd 97, Helvetia 10, and Újfehértó, 3 cultivars were studied in variety collections. Observations were made on the blooming phenology (start, main time, end and length of the bloom period), on the blooming dynamics (the rate of the open flowers counted every day), on the receptivity of sexual organs, on the fruit set following self- and open-pollination and on the effect of association of varieties in the orchards (choice, rate and placement of pollinisers).

Based on the results the rate of the overlap of the blooming times were calculated and varieties were assigned into five bloom time groups according to their main bloom. Self-fertility conditioned by natural self pollination was studied and good pollinisers were chosen (sweet, sour and duke cherry varieties) for the self-sterile and partially self-fertile varieties.

The necessity of bee pollination was proved by different pollination methods: natural self-pollination, artificial self-pollination, open pollination. Summary: Experiments were conducted during the period between 1972 and 2002 at three sites in Hungary. At Érd 97, Helvetia 10, and Újfehértó, 3 cultivars were studied in variety collections. Observations were made on the flowering phenology (start, main time, end and length of the bloom period), on the flowering dynamics (the rate of the open flowers counted every day), on the receptivity of sexual organs, on the fruit set following self- and open-pollination and on the effect of association of varieties in the orchards (choice, rate and placement of pollinisers).

Flower constancy of honeybees (Apis mellifera L.) to blooming pear plantations

Studies were made on the composition of pollen loads of honeybees captured at the flowers of blooming pear trees in pear plantations. Also the foraging behaviour of honeybees was observed. Overwhelming majority of honeybees visiting the flowers of 13 pear cultivars in 1996 were pollen gatherers (95.6 per cent). Proportion of pure nectar gatherers was as low as some 3.7 per cent and no more than 0.7 per cent performed mixed behaviour. The analysis of pollen loads of bees collected at pear flowers in blooming pear plantations showed that fidelity was as high as 89-90 per cent towards pear, higher than for another fruit species in other studies. Even those plant species that are regarded to be strong competitors of blooming fruit trees in the literature (Taraxacum officinale, Stellaria media, Lamium purpureum) were scarcely represented in the loads. Accordingly, honeybees can be much more important and more effective pollinating agents of pear cultivars than generally believed.


Spore dispersal, diurnal pattern and viability of Monilinia spp. conidia and the relationship with weather components in an organic apple orchard

In a two-year Hungarian study, spore dispersal diurnal periodicity and viability of Monilinia spp. and their relation to weather components were determined in an organic apple orchard. Conidia of Monilinia spp. were first trapped in late May in both years. Low number of conidia were trapped until end-June. Thereafter, number of conidia continuously increased until harvest. Conidia in a 24-h period showed diurnal periodicity pattern, with th highest concentration in the afternoon hours. Spore viability with FDA staining showed that viability of
conidia ranged from 45 to 70% with showing lower viability in the dry than in the wet days in both years. Temperature and relative humidity correlated positively with mean hourly conidia numbers in both years. Mean hourly rainfall was negatively but poorly correlated with conidiacatches in both years. Results were compared and discussed with previous observations.

Virus and virus-like diseases of grapevine in Hungary

Viruses and viroids are submicroscopic infectious particles which can cause disease symptoms on grapevine. These parasites are depending completely on the energy metabolism of the plant cell. To enter the host cell plant viruses depend on injuries or on transmission via invertebrates (insects, nematodes, etc.). Viruses are classified by many characters including particle morphology, host range and information content of the genome. At present about 70 viruses including 7 viroids infecting grapevine are known. In single or mixed infections they are potentially detrimental to the quality and quantity of grape production in any growing area of the world. Some viruses can cause severe economic damage in vineyards. In Hungary many important viruses and viroids have been detected in grape. This review summarises characteristics of viruses and the results of detection and characterization of virus and virus like diseases of grapevine in Hungary. The identification of the causal agent, its transmission, geographical distribution and the development of the diagnostic methods are also discussed.

Fruit drop: I. Specific characteristics and varietal properties of fruit drop

The basic conditions of fruit set (synchronic bloom, transfer of pollen, etc.) still do decide definitely the fate of the flower in spite of the best weather conditions. Beyond a set quantity of fruits, the tree is unable to bring up larger load. A system of autoregulation works in the background and causes the drop of a fraction of fruits in spite of the accomplished fertilisation and the equality of physiological precedents. This study discuss this physiological process based on the international specific literature. The further development of fruits maintained on the tree depends mainly on the growing conditions (e.g. water, supply of nutrients, weather adversities, pruning, fruit thinning, biotic damages, etc.), which may cause on their own turn fruit drop especially at the time of approaching maturity.

In vitro comparative study of two Arundo donax L. ecotypes’ selenium tolerance

Selenium tolerance of two somatic embryo-derived Arundo donax L. ecotypes (Blossom, 20SZ) were compared in in vitro culture. Sodium-selenate (1 – 100 mg L-1) as known the most phytoavailable selenium form and the less studied red elemental nanoselenium (100 mg L-1) were applied as selenium treatments. Basis on the results Blossom ecotype seemed to be more sensitive to the sodium-selenate than 20SZ. Inhibiting effect of selenate was effectuated above 10 mg L-1 in case of Blossom, which was manifested in decreased survival rate and growing parameters. Contrast to this 20SZ could tolerate the selenate ≤ 20 mg L-1 without any toxic symptoms. Lower selenate tolerance of Blossom could be explained with higher selenium accumulation. Both of two ecotypes could also uptake and accumulate the red elemental nanoselenium however in much less extent compared to selenate.

Spatial and temporal variation of extremely abundant maxima of precipitation in Hungary during the period between 1951 and 2010

The study deals with the accumulated database of 16 meteorological stations in Hungary during a period of 60 years. The purpose was to reveal the spatial and temporal structure of the appearance of extreme values in the daily distribution of data concerning precipitation. We strived to answer the question whether the frequency of incidences of daily maxima did they change or not during the 60 year-long period in the main growing regions of the country. It is demonstrated on geographical maps how the size and frequency of precipitation episodes ensued, and what are the typical traits of changes in intensity as well as in frequency of happenings projected according to their spatial and temporal distribution. From the point of view of fruit and vegetable growing, it is of prime interest what kind of frequency and intensity of changes occurred in precipitation. The temporal distribution of extremities though did not seem to change signifi cantly in some areas, but the recognition of changes may help conspicuously the planning and the choice between alternatives of species and varieties as well as technologies of horticultural managements for the long run. Extremely intense rains during a short time may cause erosion and stagnant water, thus we have to know what are the odds of risk. The temporary distribution of changes helps us to judge upon the reality of anxieties, which are expected according to the existence of trends. Seasonal or monthly distribution is visualised by maps, what is expected and what is accidental as for a decision in planning. The spatial distribution of coeffi cients of variation help us to decide what is the local chance of extreme happenings at different parts of the country and what is its coeffi cient of uncertainty. The risk of any undertaking dependent on conditions of weather could be expressed numerically by a coeffi cient of risk.

The tests of effectiveness of Frostbuster under excessive weather conditions in an apricot plantation

Frostbuster is a new system, engine and technology, developed to protect fruit plantations from the frost damage. In order to raise domestic experiences and measurements, experimental approach has been initiated to prove the utility of the system under excessively low temperature in the plantation of the Siófoki Gyümölcstermesztési Zrt (Fruit Growing Co. Siófok). The first opportunity ensued in the night of February 23-24, 2011, when the temperature sank to 12°C below zero. The question was to see whether we could prevent the drop of temperature by the frostbuster technique. The margin of an anticyclone staying on East Europe secured a stable condition to make tests. The only difference from the imaginable conditions of dangerous frosts was the heat keeping capacity of trees was weak, much inferior than compared with trees in full boom. As a consequence, the tree rows represented much lower heat-capacity and cooled down much quicker than blooming trees in springtime, i.e. their temperature was more variable. The other difference was, compared with an episode in spring that the hard frost lasted much longer than usually in spring. For testing the system, those conditions had even more advantage. Six meteorological stations helped us in measurement. Data-collectors were timed to 1 minute distances and the bulk of data proved to be beneficial for testing the Frostbuster. The results prove that the system is adequate to keep the temperature continuously higher than the surrounding field under excessively low temperatures. Further measurements are still needed to find the optimal solutions fitting to the growing site and its microclimate. Results presented offer a basis of further proofs.

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