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The effect of day and night temperatures on apple skin colour formation
Published February 19, 2008

The 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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Training systems of fruit trees in Hungary
Published February 23, 2000

Growing sites and soil conditions of Hungary warrant profitable production of several temperate fruits at elevated levels of quality. The climate of the Carpathian basin is a mixtures of three main climatic zones the prevalence of which may change seasonally: Atlantic, continental and Mediterranean, therefore, growing sites are rather various. ...Temperature minima of the winter and late spring frosts are the main elements of risk. In choice of the system of cultivation, regularity of yields and intensity are to be observed equally. Regular yields are particularly aimed in stone fruit cultures.

For apple and pear plantations of high density required for intense production are promoted favourably. Accessories of intense orchards (irrigation, supporting system, rootstocks, phytotechniques, etc.) are important. In peach and plum trees are trained to funnel-shape crowns, in general, intense-types are possible in plum, only. In apricots, a Hungarian speciality, the "umbrella" type of crown is applied, almost exclusively, according to Papp. In sweet and sour cherry, the harvest technique, manual or mechanised, according to the intended utilisation, are determining the form of training.

Red and black currants as small fruits are grown mostly as bushes or hedgerows without any supporting system designed to facilitate mechanical harvest. Raspberries and blackberries are grown as hedges on trellis. Gooseberry is a special case, being a low, thorny bush difficult to be picked. Thus grafted small trees are attached to a wire-trellis which helps to solve problems of plant protection too.


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Ecological drought resistance and adaptability of apple varieties
Published January 3, 2010

For adequate yields in apple plantations, during the long growing period of the fruit primordia, one of the decisive factors is water supply. Indicators of stress are valuable signs for the diagnosis of drought and necessity of watering, i.e. planning the irrigation of plantations. The aim of the present study was to find reliable signs of wate...r stress on apple trees and at the same time conclude on the drought tolerance of different varieties. The plantation of apple varieties grafted on various stocks and cultivated according to different systems (irrigated, non irrigated, integrate and biological) has been examined continuously by leaf analysis. Along the period of growing fruits, measurements were made in the field, then the leaf samples were analysed in the laboratory for composition of pigments, carbohydrates and antioxidants, as well as the histology of the tissues checked. Without irrigation, the mean leaf mass and the relative chlorophyll content (SPAD) of the variety Idared on M4 stocks increases beyond the values of 50 SPAD, whereas on M26 stock and integrated system, it declines. In the collection of varieties, grown according to the „integrated” system, during the development of fruits, ‘Gála’ and ‘Remo’ varieties have been affiliated to the “less susceptible” group regarding drought tolerance because of the leaf morphology, structure and content of SPAD and antioxidants. However, ‘Idared’ and ‘Jonagold’ belong to the “susceptible” group. To the same group are ranged the ‘Akane, Red Rome vanWell, Pink Lady’ varieties. Those varieties reacted to a short period of drought by increased production (content) of carbohydrates. Regarding changes of carbohydrate content ‘Greensleeves’ and ‘Ozark Gold’ varieties belong to the moderately water dependent (requiring) group. In the field, SPAD-tests facilitated the measurement of nutrient-uptake and incorporation, which is proved by the tight correlation between the data of SPAD and the increment of leaf weight (r=0.76–r=0.88), however, this depends on the variety too. SPAD is an indicator of water supply and is related with the density of stomata, cannot used for the selection of water-exigent varieties but for (drought) tolerant ones. In integrated culture, the (drought) susceptible varieties display (water-soluble) hydrophilic and lipophilic antioxidants (ACWand ACL resp.) the quantity of which may have some role in drought tolerance.

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Performance of sweet cherry cultivars grafted on Colt rootstock
Published June 10, 2018

In this paper growing characteristics and fruit bearing parameters of ‘Lapins’, ‘Kordia’, ‘Sweetheart’ and ‘Regina’ sweet cherry cultivars grafted on vigorous Colt rootstock were evaluated at the University of Debrecen, Pallag Experimental Station. Based on our data five years old trees can be described with homogenous strong gr...owing, but very week yielding (2.1-3.1 kg/tree), as while fruit size varies between 26.2 and 27.2 mm. Producing the examined cultivars on Colt rootstock with high plant density requires higher attention and more interventions (root pruning, sawing the trunk) during the technology.

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Security of growing habits and bud formation of German sour cherry varieties
Published December 4, 2011

Intensive sour cherry production is concerned to find the most productive varieties under special growing conditions. High planting density, adapted to manual picking or on the other hand to mechanical harvesting. Almost as important is the prolongation of the ripening season by enlarging the choice of varieties. Unfortunately, three of our fou...r leading commercial varieties are ripe almost at the same date.
Therefore, new varieties ought to be examined thoroughly. In the Pallag Experimental Station of the Debrecen University, five European varieties have been grown (’Schattenmorelle’, ’PI-SA 12,100’, ’Jade’, ’Gerema’, ’Achat’) and a Hungarian one, ’Debreceni bôtermô’ used as a check for the experiments to compare their growing and yielding habits in 2010. The plantation was three years old, standing on Prunus mahaleb rootstocks, in high density (5 x 2 m) and trained to slender spindle crowns. The results are proving that some of the varieties in
question are suitable to prolong the harvesting season. Growing habits and yields of the varieties related to the variety ’Debreceni bôtermô’ were similar or even better as ’Jade’, ’Gerema’ and ’Achat’. The ’Jade’ excelled with its vitality and ’Gerema’ with its generative character. Further studies are expected to prove the utility of
one of them at least to enlarge the ripening season on the fruit market.

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A review of the bee pollination research on temperate zone crop plants in the past decade: results and the need of further studies
Published August 14, 2002

Intense research was made on the pollination of cultivated crop plants in the temperate zone region during the past decade. Some 400 publications appeared on the subject and some additional 150 papers on the effect of pesticides to the most important pollinating insects, the honeybee and the wild bees. Progress of knowledge is discussed in this... paper based on the most important publications. Most new results relate to field crops and deciduous fruit species and much less to field vegetables and small fruits. Great effort was taken to improve insect pollination of crops grown under cover. All these are connected to the utilization of the honeybee as a pollinating agent and much less to native or managed wild bees. However, a number of questions arose partly from the results of latest pollination research and partly from practical experiences in commercial plant production. These indicate several research tasks to understand and to solve the problems possibly in the near future. The questions concentrate on the effectiveness of bee visits in the pollination of individual crop plants and their different cultivars and on the reliable estimate of the overall amount of bees as well as on the control of bee density during the flowering periods of crops for optimal, controlled pollination in the changing environment of agricultural crop production.

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