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Antioxidant capacity and total polyphenol content of Lavandula cultivars at different growing areas in Hungary
65-69.Views:318Lavandula species are worldwide grown essential oil producing medicinal plants with considerable economic value. Beside volatile oil, lavender also contains different phenolic compounds which have been less widely studied till now. Cultivation of lavender has become widespread in Hungary in the recent years, however, growers have limited knowledge on the productivity of cultivars available. In our research we were aimed to studying the antioxidant capacity and total polyphenol content of samples collected in two growing areas (Dörgicse and Szomód) from flowers of two L. angustifolia (‘Hidcote’, ‘Munstead’) and two L. × intermedia (‘Grosso’, Grappenhall’) varieties, during the full blooming period of 2017. Antioxidant capacity of the samples was determined by FRAP assay (Benzie and Strain, 1996), while total polyphenol content (TPC) was measured by a modified method of Singleton and Rossi (1965). According to our results, varieties of L. × intermedia showed higher values of antioxidant capacity and of total polyphenol content, than those of L. angustifolia cultivars. Among them, both the antioxidant capacity (179.6 mg AAE/g DW) and total polyphenol content values (152.4 mg GAE/g DW) of ’Grosso’ from Dörgicse were the highest. Concerning FRAP values of all the cultivars investigated, larger variability were found in Dörgicse, than in Szomód. Regarding the effect of growing area, each cultivar represented similar FRAP values in Dörgicse and in Szomód, except for ’Grosso’. However, in the case of TPC values, higher variability was observed between the growing areas, especially in the case of ’Grosso’. In the future our studies on lavender polyphenols will be completed with qualitative evaluation of the values obtained by HPLC analysis.
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Fruit drop: II. Biological background of flower and fruit drop
103-108.Views:294The most important components of fruit drop are: the rootstock, the combination of polliniser varieties, the conditions depending of nutrition, the extent and timing of the administration of fertilisers, the moments of water stress and the timing of agrotechnical interventions. Further adversities may appear as flushes of heat and drought, the rainy spring weather during the blooming period as well as the excessive hot, cool or windy weather impairing pollination, moreover, the appearance of diseases and pests all influence the fate of flowers of growing and become ripe fruits. As generally maintained, dry springs are causing severe fruit drop.
In analysing the endogenous and environmental causes of drop of the generative organs (flowers and fruits), the model of leaf abscission has been used, as a study of the excised, well defined abscission zone (AZ) seemed to be an adequate approach to the question. Comparing the effects active in the abscission of fruit with those of the excised leaf stem differences are observed as well as analogies between the anatomy and the accumulation of ethylene in the respective abscission tissues.
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Temporal changes of the frequency of spring frost damages in the main fruit growing regions in Western Hungary and in East Hungary
81-87.Views:220Most of the risk in Hungarian fruit growing is the damage caused by late spring frosts. The frequency of late frosts seems to increase nowadays. The aim of the study was to check this contention: what is the real probability of the damages. Based on earlier experiences, the physiological LT50 function has been elaborated for new fruit varieties, which are eligible to moderate the danger when being threatened by frost. By means of this technique, the probability of freezing is distinguished between frost susceptible, frost resistant and medium frost resistant fruit species and varieties around their blooming time. The degree of frost damage depends on the duration and severity of the low temperature and not at least on the frost tolerance of the plant. For that purpose, the frequencies of frost damages were studied at two Transdanubian and two Trans-Tisza fruit growing sites by means of a meteorological database for the 60-year-long period 1951–2010. Being aware of the LT50 values changing during the phonological phases of the fruit trees from budding, bloom, fruit set and fruit growth, the number and date of critical (frosty) days could be settled. An important role is attributed to the orographic relief and the height above the sea level of the site, as 20–30 m differences and expositions may become decisive within the same plantation. The spatial distribution of damages is also dependent on the air circulations within the Carpathian basin. At the southern and northern borders of the country, especially valley bottoms represent additional risks of frost. Most spring frost damages are experienced in April 20–22, and cause heavy damages by temperature minima between – 3°C and – 6°C. The severity of damage depends largely on the temperature of the preceding few days. The earlier bloom the heavier damage is expected. The study is emphasising the importance of the varieties. Frost tolerance of some varieties may lower the risk of spring frosts by 40–50%, as experienced on the plantations. The quantifi cation of the risks based on data raised during the last years will be suitable to defi ne the security of yields of each growing site successfully.
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Overwintering capability and spring population size of honeybee colonies (Apis mellifera L.) in Hungary
153-156.Views:107Honeybee races and ecotypes of different genetic background have different population development in spring. Some of them can reach the necessary population size by the beginning of Robinia pseudoacacia (black locust) blooming period. There were significant differences in the spring population development between the colonies of different genetic background. The Italian races (A. m. ligustica) and their cross-breeds over-wintered poorly in Hungary, their spring population was low and they collected small amount of Robinia honey. The Austrian improved Carniolan (A. m. carnica) colonies over-wintered well, they had the largest spring population in both years. There was no significant difference between the size of the spring population of the same colonies of different genetic background in 1995 and 1996. The rate of the population development of the colonies was different in the two examined years. There was strong correlation (r = 0.8) between the spring population size and the Robinia honey yield, and between the mid-April population size and the Robinia honey yield of the colony groups of different genetic background. Spring population size also important in the effective pollination of fruit tree species that bloom earlier than the black locust trees.
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Simultaneousness of reproductive organs of sour cherry cultivars adaptable to Iranian climatic condition
25-31.Views:205Observations were made on simultaneousness of pollen shedding and stigma viability ratio, to clarify the phenology of reproductive organs of nine economically important sour cherry (Prunus cerasus L.) cultivars (‘Érdi bôtermô‘, ‘Debreceni bőtermő‘, ‘Csengődi‘, ‘Kántorjánosi 3‘, ‘Újfehértói fürtös‘, ‘Petri‘, ‘Eva‘, ‘Oblascinszka‘, and ‘Pándy 279’). The main aim was investigation the possible influence of environmental cues in timing and development of phenophases and also responses of different cultivars to seasonal cues. Likely effects of climatic changes on phenological development patterns were also considered. Results showed important aspects of the reproductive biology of sour cherry flowers. The amplitude of the phenophase “beginning of blossoming” between cultivars did not exceed 6 days. There is a maximum 3 day difference in the blooming length of different directions in each cultivar. ‘Pándy 279‘ showed high variability when the position of flowers changed on the tree shoots. ‘Újfehértói fürtös‘ was stable in all four directions of the tree. The pollen shedding period and stigma viability ratio were synchronous. Pollen shedding phenomenon simultaneously occurred with the secretary activities of stigmas in all examined cultivars. Distribution of pollen shedding over the secretary activity of stigmas is almost good. In all five cultivars maximum pollen shedding occurred when the temperature was high during the day. In general the results of this experiment and our previous studies clearly demonstrate that the Pándy groups not recommended for plantation in new orchards of Iran.
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Effect of late spring frost event on nutrition aspects of a sour cherry orchard in East Hungary
93-97.Views:249Similarly to 2007, 2011 was also critical year for fruit growers in Eastern-Hungary. Serious frost damage was observed at late blooming period (6 May (T=-1.6°C)) in this region, which caused approximately 60-65% of fruit loss. The aim of this study is to investigate the effects of a spring frost event on nutrient uptake and status of the trees of a sour cherry plantation at Újfehértó. The symptoms of frost were observed visually. This visual observation was confirmed by SPAD readings. The frost affected the macroand micronutrient contents of leaves. It was found that the frost affected the nutrient uptake negatively, but the effect of it was not significantly sometimes. It can be stated that the nutrient demand of trees can be supplied only under even worse conditions.
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Some biological properties of new sweet cherry cultivars in Bulgaria and their susceptibility to Blumeriella jaapii
95-97.Views:231Investigations were made on 12 sweet cherry cultivars (‘13-S-22-8’, 'Sunburst', `Kozerska'., 'NY 13791', 'Royalton', 'NY 13688', 'Hartland', `Sumerset', 'Pollax', 'Patriotka Krima', 'Castor', and `Lapins') in an experimental orchard of cherry cultivar collection in the Institute of Agriculture at Kyustendil, Bulgaria during the period of 1997-2003. The trees were planted in 1996. All cultivars were grafted on Prunus mahaleb. Four biological properties of the cultivars were assessed such as blooming time, resistance to late spring frost, fruit ripening and fruit mass. Among cultivars, a good resistance to late spring frost was observed on cultivar 'Sunburst'. The fruit mass varied between 4.2 g (cv. 'Patriotka Krima') and 8.5 g (cv. `Sunburst'). The susceptibility of the cherry cultivars to cherry leaf spot caused by Blumeriella jaapii was assessed in mid-September in each year. The estimation of the rate of attack was made according to the grade of Townsend and Neuberger. All cultivars showed symptoms of cherry leaf spot but the degree of susceptibility was different. Cultivar `Patriotka Krima' was the least susceptible, while cultivar `Somerset' was the most susceptible to Blumeriella jaapii.