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Sugar composition of floral nectar in sour cherry cultivars
109-113.Views:438The composition of floral nectar in sour cherry cultivars studied in 1997 at Újfehértó was in agreement with our previous data, the three most frequent sugar components being glucose, fructose and sucrose. Nectar secreted at night is generally more diluted than nectar produced during the day. None of the nectar samples produced at night reached the threshold value (100 mg/ml) of bee visitation. In the majority of cultivars the difference in concentration between night and day nectar is not too high, but in two cultivars, 'Korai pipacs' and ‘Újfehértói fürtös’ the difference is quite significant. Most sucrose was found in the nectar of cvs. 'Érdi jubileum' and ‘Újfehértói fürtös’, but a high amount of sucrose was measured also in the flowers of 'Korai pipacs' and 'Meteor USA'. Nectar concentration varies from opening of the flower to petal fall to a smaller or greater degree, depending on the given cultivar. From the 9 sour cherry cultivars studied ‘Újfehértói fürtös’ and Tandy 48' had the most attractive nectar for bees. There was no correlation between nectar composition and free fertilisation. On the basis of nectar composition the majority of the sour cherry cultivars studied can be classified into the sucrose-rich category; only one cultivar, 'Érdi jubileum' had a sucrose-dominant secretory product. The composition of nectar in the studied sour cherry cultivars is preferred by bees.
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Review of sweet and sour cherry incompatibility
111-116.Views:301Cherry incompatibility has widely been studied from the beginning of the twentieth century. As a consequence of the valuable results cherry has become a model for incompatibility research of other plant species. This study provides a detailed information about incompatibility of sweet and sour cherry based on several Hungarian and international literature sources from the last 100 years. The study gave details about the traditional and molecular base of incompatibility of sweet and sour cherry.
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Stimulating effect of distilled water
47-49.Views:351It is an early observation that plants in poor soil are developing roots quicker and more abundantly than on rich one. There is a similar correlation between the nutrient status of medium and adventitious root formation.
In order to throw more light on the background of this strange phenomenon we started a systematic experimental program in which the biological effects of distilled water as model factor was investigated.
The experiments proved that the root formation of Pinto bean (Phaseolus vulgaris L.) cuttings with 3 cm long hypocotyls was promoted by distilled water.
The phenomenon above accompanied with slower decline and faster recovery of total and also water-soluble protein content, more intensive efflux of amino acids, greater amount of tryptophane and increased uptake of water compared to those in control hypocotyls. From other data obtained we may suspect that some additional active substance unknown for us also contributes to the stimulation of root initiation in distilled water.
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The effect of Regalis® (prohexadione calcium) on the reduction of fire blight (Erwinia amylovora) severity in apple trees
61-66.Views:366Due to the lack of effective and non-phytotoxic materials for control of the blossom and shoot blight phase of fire blight in pome fruit trees, two novel control strategies have emerged: shoot growth retardation by bioregulators and applying resistance inducer compounds. Prohexadione calcium (ProCa) is the active ingredient of the bioregulator Regalis® registered in several European countries. The reduction of shoot growth elongation is the most obvious effect of ProCa. Furthermore, it causes significant changes in the spectrum of flavonoids and their phenolic precursors, leading to the considerable reduction of susceptibility to fire blight.
In Poland, potted one-year-old apple trees of cvs. Gala Must grafted on M.26 and Sampion on M.9 (in 2001) as well as Gala Must on P.60 (in 2002) were treated with Regalis® at a range of concentration of 250, 150 or 150 + 100 ppm, respectively. The inoculation of shoots was made with the strain No.691 of E. amylovora (107 cfu/ml), on the 7th and 21st'day after treatments with Regalis. In Hungary, during the years of 2002 and 2003 one-year-old container grown apple trees of the cvs. Idared/M.9 and Freedom/M.9 were treated with the prohexadione-Ca, the active ingredient of Regalis® 100, 150 or 200 ppm, two weeks before inoculation with the Ea 1 strain of E. amylovora (107 cfu/m1).
In Poland, the suppression of fire blight in shoots reached up to 80%, depending on concentration and application time of Regalis®. In Hungary, the effect of prohexadione-Ca treatments, determined by the length of necrotic lesion developed, proved to be better than that of streptomycin used for comparison.
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Contributions to the resumption of growth in ecodormant buds of apple
35-40.Views:269The resumption of development in ecodormant buds in terms of establishing a functional vascular connection between the inflorescence primordia and spur tissues in apple trees was investigated. Differentiation of the xylem elements could be observed first in the pedicel of the flower primordium, in the middle of January. Much later (at the beginning of April) there were mature xylem vessels in the wall of the receptacle and, merely a procambial strand for the ovule primordium which was at this time an undifferentiated protrusion of meristematic cells, only. As for phenological development of buds incubated at a temperature of 20 °C, it was the slowest in buds sampled in January, faster in buds sampled in the middle of February and, buds from the middle of March responded very quickly. The function of temperatures needed both for xylem differentiation and for the flower primordium to achieve maturity is pointed out. The nature of frost damage in vessel elements, as well the relationship between chilling requirement and growth features of apple cultivars will be discussed.
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Rootstock effects on fruit drop and quality of 'Arlet' apples
69-75.Views:947The aim of this study is to investigate the effect of different growth inducing rootstocks on fruit drop of apple. This research was conducted for 3 years at Nagykutas, Western Hungary on apple cv. 'Arlet'. For the experiments, 3 different growth inducing rootstocks were choosen: M.9 (weak), MM.106 (moderate) and crabapple seedling (strong). There were 3 fruit shedding periods on the trees grafted M.9 and MM.106 rootstocks, but in the case of crabapple seedling, only 2 were found. The measure of fruit drop was closely related to seed count of fruits; seed number was the lowest, fruit drop was the highest. The lowest seed number was counted in fruits from trees on crabapple seedling. Seasonal changes of leaf:fruit ratio mainly depended on shoot growth and fruit drop. The rise of the curve of leaf:fruit ratio was very important during the first phase of fruit development, in especially at the end of June and in the beginning of July. The cause of this is that first and second periods of fruit drop appeared during this term. The rise of the curve was important in the beginning of June and the end of July on crabapple seedling. Decreasing tendency of quality parameters was found of fruits from trees on M.9, MM.106 and seedling rootstocks, except flesh firmness which was the highest in fruits from trees on crabapple seedling.
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Nutrient demand of stone fruits
19-23.Views:259Effects of nitrogen, phosphorus and potassium fertilization were investigated on the change of nutrient content, vegetative and generative production of apricot, peach and sour cherry trees, as well as on frost hardiness in long term experiments. Nitrogen and phosphorus fertilization increased only the concentration of these elements in cherry leaves without effect on growth and yield. Consequent potassium effect was proved on these stone fruit species. Effect on yield appeared following the first higher crop load.
Potassium supply has positive effect on frost hardiness of apricot and sour cherry flowers and peach flower buds.
In peach, the lime content of soil decreased the yield but it could be compensated by potassium dressing to some extent. Favourable nutrient boundary values were determined for soil and foliage.
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The effect of day and night temperatures on apple skin colour formation
21-25.Views:1091The 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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Fruit drop: I. Specific characteristics and varietal properties of fruit drop
59-67.Views:15224The 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.
