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Effects of crop load on tree water use in apple (Malus x domestica Borkh.)
29-31.Views:126Sap flow rate measurements were carried out during two consecutive ('on' and 'off') years in an apple orchard cv. 'Florina' M.26 to analyse the effects of various crop load on tree water use. Sap flow rate was measured by thermal dissipation method in trunks of nine trees from June to the harvest. Crop load was between 0.2-9.0 fruits • cm -2 of trunk cross section area (equal to 0.5-35.0 fruits•m-2 of leaf area), trunk diameter varied between 4.7-8.7 cm.
Total leaf area was estimated by leaf counting or using shoot girth and leaf area relationship. In both years, fruit growth rate was determined by measuring diameter of 280 marked fruits with 7 days frequency. Fruit volume calculated as a function of fruit diameter based on a previously determined relationship.
Total leaf area of trees ranged from 4.4 to 19.5 m2 and it was closely related to trunk cross section area. At high crop load the fruit growth rate peaked in August with 0.51.tree-l.day-1 and the leaf area specific total fruit volume reached 61 m2 before the harvest.
There was a linear relationship between total leaf area and daily water use, while the leaf area specific water use was influenced by crop load rate. The relationship was described by piecewise linear regression with the breakpoint at crop load rate of 12 fruits•m2 of leaf area. At low crop load the slope of the fitted regression line was less than at high crop load rate.
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The tests of effectiveness of Frostbuster under excessive weather conditions in an apricot plantation
87-91.Views:275Frostbuster 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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The effect of day and night temperatures on apple skin colour formation
21-25.Views:245The colour of fruits is considered to be an important quality indicator. Saleability greatly depends on how well covered the colour is of the specific type of fruits. It is a well-known phenomenon by growers that apples get nicer colours in one year while in other years the basically red and green colour cultivars can be differentiated only by morphological characteristic features. Cover colour is one of the phenometric variables and it is a well-known fact that significant differences can be experienced year by year. The experienced oscillation can be the cause of inappropriate water- and nutriment supply, however it can be the result of some kind of plant disease, extremely high or low temperature, setting rate above the average and outstanding fruit density. In the present examination it is postulated that the degree of cover colour is mostly influenced by day and night temperature. Therefore, our study aims to find out whether it is true or not. Cover colour belongs to those phenometric characteristic features, only the final value of which is taken into consideration; due to their nature of establishment or forming time it seems useless to follow closely the change in the time of vegetation. However, determining the start of colouring and knowing the dynamics of full colouring could carry very important information for growers. If it is possible to determine the curve describing the time change of colouring, we have a possibility to estimate it by means of enviroment variables. So it is also possible to model pigmentation in the future. Knowing this, colouring irrigation could be made more efficient in the future. For this, as a first step, it is inevitable to find out what the relationship is between the main meteorogical variables, namely day and night temperature and the difference between day and night temperature, and colour cover. In this study we summarize and show these interrelations.
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Spatial and temporal variation of extremely abundant maxima of precipitation in Hungary during the period between 1951 and 2010
107-114.Views:357The 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.
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Some aspects of disease management of cherry leaf spot (Blumeriella jaapii) with special reference to pesticide use
45-49.Views:499In this review, some aspects of disease management of cherry leaf spot (Blumeriella jaapii) are summarised with special reference to pesticide use. In the first part of the review, we show the non-chemical control approach (e. g. removal of fallen leaves, planting resistant cultivar) against leaf spot. In the second part of the review, the effect of pesticides including fertilizers (urea) and fungicides on cherry leaf spot are discussed. Special attention are given to the fungicides of copper, dodine, captafol, captan, benomil, chlorothalonil, sterol demethylation inhibitors (e.g. fenarimol, fenbuconazole, myclobutanil, tebuconazole), and strobilurins about their effectiveness against cherry leaf spot. In the final part of the review, possibilities of cherry leaf spot control are discussed in integrated and organic cherry orchards.
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Fruit injury in organic fruit production and its relationship to brown rot caused by Monilinia spp.
7-9.Views:229In a two-year Hungarian study, the temporal progress of brown rot incidence and various injury types were studied in organic fruit orchards and the relationship between brown rot and injury types was determined. Results showed that brown rot reached an almost 20% incidence level in both years. Total injury incidence reached up to 5.3 and 19.8% in the two years. In all cases, insect injury incidence was the highest among injury types in most assessment dates. Incidence levels of other injury types (bird injury, mechanical injury and other injury) began to increase, but none of those reached levels >4%. Pearson’s correlation coefficients showed that brown rot incidence correlated significantly with the incidence of insect injury. In addition, brown rot incidence and the incidence levels of bird injuries was also significantly correlated. High injury and brown rot incidence levels suggest further improvements on organic fruit protection.
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Recent developments in biochemical characterization of Vitis vinifera L. varieties in Hungary
57-61.Views:168Isoelectric focusing is an effective and well reproducible method to provide information for identification of various plant species and clones if breeding or other genetic modification(s) for a given species are reflected in changes of an isozyme pattern. The method has been used for characterization of plant proteins and enzymes and for identification of various species and varieties. Our aim was to continue our several-year-work carried out on a wide variety of grapevine varieties and to reveal whether analyses of esterase and peroxidase isozyme patterns are suitable to distinguish various grapevine varieties. Therefore we compared esterase and peroxidase isozyme patterns of various species. Plant samples were obtained from Szigetcsep, Kecskemet, Tokaj and Eger. The following samples were analyzed: Pinot gris, noir, blanc, Chardonnay, Riesling Theses, Chasselas from Szigetcs6p, Bianca and his parents Eger2 and Bouvier from Kecskemet, Furmint and Hárslevelű from Tokaj, Kékfrankos and Zweigelt from Eger. To identify various species according to their esterase isozyme patterns the after blooming phenological phase while according to their peroxidase isozyme pattern the dormant phenological phase was found as optimal sampling time.
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Effects of excessive weather on the micro-climate of apple plantations under the hail protection nets
81-85.Views:307The general utilisation of hail nets is spreading all over the world and in Hungary too. Hail nets are at present the only tool, which
is able to prevent heavy hail damage in agricultural crops. Besides its numerous advantages, there are also deleterious side effects, e.g. it
changes the microclimate of the crop stand. Our study aimed to observe the differences, which characterise the physical status of crop stands
under the protection of hail nets compared with the stands in open air under various meteorological conditions: high or low temperature, calm
or windy atmosphere and their possible combinations. The results indicated that on hot and calm days the difference may attain 3–4° C. On
cool summer days, the difference was only 1.5 ºC. The hail net influences the relative humidity of the air, which means on ho summer days
often 7-8% differences. Conditions of radiation may also differ conspicuously. Measurements prove the reduced global radiation on sunny
summer days to 70%. This impairs as a rule the development of fruits reducing their quality and also its quantitative traits. Sunburn is, on the
other hand, significantly prevented by shadow. -
Relationship between several meteorological factors and phenological features of apple cultivars
13-19.Views:238The trees observed are grown at Ofeherto, Eastern Hungary in the plantation of an assortment (gene bank) with 586 apple cultivars. Each of the cultivars were observed as for their dates of subsequent phenophases, the beginning of bloom, main bloom and the end of bloom over a period between 1984 and 2001. during this period the meteorological data-base keeps the following variables: daily means of temperature (°C), daily maximum temperature (°C), daily minimum temperature (°C), daily precipitation sums (mm), daily sums of sunny hours, daily means of the differences between the day-time and night-time temperatures (°C), average differences between temperatures of successive daily means (°C). Between the 90th and 147th day of the year over the 18 years of observation. The early blooming cultivars start blooming at 10-21April. The cultivars of intermediate bloom start at the interval 20 April to 3 May, whereas the late blooming group start at 2-10 May. Among the meteorological variables of the former autumnal and hibernal periods, the hibernal maxima were the most active factor influencing the start of bloom in the subsequent spring.
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Technologies developed to avoid frost damages caused by late frost during bloom in the fruit growing regions of Siófok and Debrecen
99-105.Views:386The aim of the study was to fi nd out which of the methods used to avoid damages of late frosts would be the most effective for the fruit growing practice. Three technologies have been tested in the regions of Siófok and Debrecen-Pallag. The antifrost irrigation proved to be the most advantageous. For that purpose microjet sprayers are used, which are thrifty and do not need for that purpose large containers. With the aim to secure an even distribution of water, the sprayers are distributed on three levels: above and inside of the crown as well as on the level of trunks. On a large scale, a single microjet above the crown level would be suffi cient. By means of a detailed analysis served to set the optimum intervals between spraying phases: with each 15, 10, 5 and 3 minutes during half a minute. The synchronous presence of water and ice below the freezing point, the released freezing heat plus the water used much above the freezing point (9–10 °C) altogether maintains the temperature above around 0°C near the fl owers or growing fruitlets, meanwhile, the surrounding air cools down to –8 °C. The effectiveness of the generally used anti-frost would be increased substantially by the former application of cooling irrigation, which delays the blooming date. The Frostbuster represents a new technology developed for the same purpose of frost defence. It uses butane burning and produces high (80-90°C) temperature with a strong blast of air. On the protected area sensors have been distributed for measuring temperature and relative humidity. The means of the measurements proved a rise of temperature, which was suffi cient to save the fruit trees until the difference is less than –3–3.5 °C. Our analyses stated that paraffi n candles avert the frost until –4 °C. Its success depends largely on the intensity of air movements. A small wind would be enough to frustrate the effect. The results show clearly the utility of Frostbuster and paraffi n candle combined is approved.
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Connection of fertilization conditions of sour cherry and meteorological parameters
17-21.Views:241Our 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.