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Some flower characters, variety features and environmental effects affecting bee pollination of pear (Pyrus communis L.): a review of the results of latest research
59-66.Views:148Intensive research has been implemented on different aspects of the bee pollination of pear in Hungary in the past decade, extending to the following topics: the effect of the opening sequence of the flowers within the inflorescence of pear cultivars on the effectiveness of bee pollination; the nectar production of flowers of pear cultivars; intensity of honeybee visitation and their foraging behaviour at the flowers of pear cultivars; flower constancy of honeybees to pear plantations; competition by weeds in bloom for bee pollination in flowering pear orchards; and some aspects to the bee pollination strategies of pear plantations (the effect of the limitation of bee pollination period on the set and the yield, possible compensation of frost damage of flowers by bee pollination in pear orchards, the optimal size of single cultivar block in pear plantations). The results of these studies are reviewed in this paper and some important aspects that need further studies are outlined.
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Nectar production and pollination in peach
123-126.Views:222Observations were made at two growing sites, Siófok and Szatymaz, in the years 1998 and 1999, on 16 peach varieties. The production of nectar was measured, the foraging behaviour of bees, fruit set and the effect of exclusion of bee visits for different periods were observed systematically.
Production of nectar confirmed earlier data, 9.09 mg per flower in average. There was large variation due to variety and date of observation. Bee visits were relatively abundant. At favourable weather, 1 to 30 visits/flower/day occurred in the average. Artificial hand pollination increased fruit set, substantially. Open pollination yielded superior fruit set than self pollination, without bees. Supplementary bee pollination can be regarded to be beneficial to peach production as well.
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The effect of rootstock on the nectar production of apple cultivar `Idared'
15-25.Views:128Approaches based on the daily rhythm of apple flowers provide a new stage in nectar research, where the synchronous functioning of sexual organs is studied. In the flower biological studies the insect attraction of flowers was also studied. The two most important factors of insect attraction are the pollen- and nectar production of the flowers. From 1993 to 1998 we studied the food, that flower had to offer for the pollinating insects at different times of the day.
Studies were carried out on 'Idared', one of the hybrids of 'Jonathan' apple cultivar. The fruit of 'Idared' is bigger than the fruit of `Jonathan'. It is bright red, transportable, has a bigger productivity and is not subject to Jonathan-spots. Concerning its inner characteristics, it is juicy, the flesh consistency is better than that of 'Jonathan', but its acid/sugar ratio is worse (Sansavini et al. 1981).
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Effect of boron nutrition on nutrient uptake and fruit quality of tart cherry in Eastern Hungary
45-48.Views:251Effect of the foliar boron (B) application on nutrient uptake and fruit quality of tart cherry (Prunus cerasus L.) was investigated from 2008 to 2009 on mature four favourite Hungarian tart cherry cultivars like ‘Oblacsinszka’, ‘Érdi bôtermő’, ‘Újfehértói fürtös’ and ‘Petri’. Tart cherry trees grown in Eastern Hungary (Újfehértó) on an acidic sandy soil with low B content. Trees were treated with B by foliar application (0.5% B) at full bloom and untreated with B served as a control. B sprays strongly affected on B content of inflorescences. However, B sprays had no consistent effect on summer leaf B status. In our experiment stronger year effect was observed at leaf B status than flower B status. The effectiveness of early spring boron applications are limited and mostly affected the flower B status only. Moreover, treatments had inconsistent effect on studied fruit inner parameters. Monosaccharides, vitamin C and organic acid contents of sour cherry were stronger affected by cultivars than applied treatments.
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The expression of the primigenic dominance in the flowering and fruit set of selected apple cultivars on different growth inducing rootstocks
27-31.Views:199Authors investigated the expression of the primigenic dominance in the flowering and fruit from open and self pollination of four apple cultivars ('Gala Royal', 'Golden Smoothee', Pink Lady' and 'Vista Bella') during two consecutive years in Western Hungary on three different growth inducing rootstocks (M. 9, MM. 106 and seedling). There were not significant differences in the effect of the rootstocks on the flowering order in a flower cluster. Significant difference in the fruit set in open pollination was found among individual flowers in a cluster, mostly between the king bloom and the second flower. The rate of the fruit set from self-pollination was very low without any significant difference among individual flowers in the cluster.
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Sex expression of flowers in cultivated sweet and sour cherries
50-52.Views:149During the period of 1968-1972 nine sweet cherry varieties were investigated by the author on mazzard seedling rootstock, moreover cv. Germersdorfi óriás and cv. Münchebergi korai sweet cherry cultivars grafted on mahaleb, cv. Korponai and cv. Sukorói cherries were observed on rootstocks of cv. Cigánymeggy sour cherry seedling, too.
Yet, there are other relations between the different parts of sweet cherry flowers too, which perhaps indicate the effect of rootstocks in Cerasus scions. The flower structure shows feminine character on mahaleb, the effect is intermediate on mazzard, however, the sour cherry rootstock strengthens the male character.
Four sour cherry varieties as cv. Cigánymeggy C. 404. cv. Érdi nagygyümölcsű, cv. Meteor korai and cv. Pándy C. 101 were studied on three rootstocks: mazzard, mahaleb and Cigánymeggy C. 215 seedling rootstocks between 1976 and 1980.
The pistil length, stamen number and relative stamen number diverged significantly on different rootstocks. The results revealed a close negative correlation between the pistil length and stamen number, furthermore noticing that, in the self-fertile cv. Meteor korai and cv. Újfehértói fürtös presented increasing of the relative stamen number, so the fertility decreased, while in the case of self-sterile varieties the change was favourable.
Summing up the results, it is obvious, that the fertility of flowers can be modified by rootstocks and the ecological factors cause sex reversions on different combinations.
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Comparative study of different fertile groups in plums
71-76.Views:165The plum traditional fruit species in Hungary, several local cultivars was born in the different grower's districts. The author that investigated, that are morphological differences between an odds find self-fertile, self sterile (with functional stamens) and male sterile plum cultivars. For it thought about main questions of a scientific debate sown up and the study this way gave reactions totalize. There were in three fertile groups 8-8 type of feature plum cultivars in periods of 1992-2001, respectively 1993-1999. It was founded by author big odds found the troops on the basis of 9 traits between. Pistil length of self sterile cultivars very typical, such as sesquipedalian flower peduncle of the self-fertile plums and the hypoandry of male sterile cultivars. The relative stamen number and the pollen viability as well significant odds gave.
The average fruit mass and sharka infection of self-fertile plums this troops extreme work. According to cultivar's averages the shark symptoms standard the right correlation the singular traits, but those one part of her with each other not shown connection.
The annuity potencies underdeveloped the troops behind and the troops within cultivar's differences had case significance. The results usable the male sterile cultivars and progeny further its investments.
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Freeze Susceptibility of Fruit Buds in 67 Apple cultivars in Hungary
29-35.Views:120Frost damage is one of the most important risks of apple production. Outstanding importance has been attributed to the frost resistance of flower-buds as decisive sites of fruit production. Browning of plants parts and tissues exposed to natural weather adversities are considered as effects of frost. In Hungary, frost damage on flower buds of both the market and new cultivars has not been assessed earlier. Observations referring to the consequences of frost damages of over four critical years, marked by their peculiar winter and spring frost hazards. Parallel observations have been made in four sites of the growing area in the Great-Plain region. 67 apple cultivars have been assessed. Each cultivar was represented by 3 trees, which were sampled at about 1-1.5 m height over ground, where the buds or inflorescences were picked for the purpose to assess the injury. The buds and flowers are cut longitudinally and rated visually according to the extent of browning of the organs and tissues. Susceptibility of different organs of the flower (pistils and anthers) were rated separately. According to our results, most resistant to spring frosts are the following cultivars: 'Gloster', 'Granny Smith' and appreciable tolerance is attributed in 'Gala' and 'Jonathan' with derivatives. Preliminary results that among the scab resistant cultivars, `Baujade', 'Rewena', 'Liberty', `Resi' and 'Renora' are rather frost resistant. Information, lacking hitherto, is obtained upon 'Reka' and 'Reglindis' as for their increased susceptibility.
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Brown rot blossom blight and fruit rot of apricot in Hungary
139-141.Views:261The aim of our two-year study was to assess incidence of brown rot blossom blight and fruit rot caused by Monilinia laxa in 2003 and 2004. Assessments of incidence were made on cv. Bergeron (susceptible to brown rot) in a flatland and a hilly growing area (at Cegléd and Gönc, respectively). In both locations, plant protection was performed according to the integrated fruit production guidelines and small untreated plots were set up for each cultivar in both years. In 2003, when weather conditions were dry and hot, brown rot incidence was low (less than 10%) on both blossoms and fruits. Monilinia laxa did not cause significantly different blossom blight and fruit rot at the hilly (Gönc) area compared to the flatland, not even in untreated plots. However, in 2004, when spring and summer weather conditions were wet and cold, Incidence reached 95% for blossom blight and 33% for fruit rot in the untreated plots. Blossom blight incidence was 1.5-2 times higher in the flatland area compared to the hilly growing area. During the blooming period of apricot, two (at flower bud stage and at full bloom) and three (at flower bud stage, at full bloom and at petal fall) fungicide applications were necessary for the successful control at Gönc and Cegléd, respectively. The difference between the two orchards was due to the fact that blooming started one week later in the hilly region (at Gone) than in the flatland region (at Cegléd), therefore, the critical weather period coincided with blooming in the orchard in the hilly region only partially. Fruit rot incidence was similar in both regions as the amount and distribution of rainfall were similar during the fruit ripening period.
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Path coefficient analysis of environmental factors influencing flight activity of Apis florea F. and seed yield in carrot (Daucus carota L.)
87-92.Views:118Foraging ecology of insect pollinators visiting carrot flowers (Daucus carota L.) was studied in relation to five environmental variables. The dwarf honeybee, Apis florea L., was the most abundant flower visitors and comprised more than 94% of the total flower visiting insects. Commencement of flight activity occurred when a minimum threshold of environmental variables was surpassed while the cessation was governed mainly by decline in values of light intensity and radiation. In between the commencement and cessation, the foraging population correlated significantly and positively with air temperature, light intensity, solar radiation and nectar-sugar concentration and negatively with relative humidity. Path coefficient analysis, however, revealed that direct effect of temperature was high and positive followed by light intensity and solar radiation while the direct effect of relative humidity was high and negative. The direct effect of nectar-sugar concentration was negative and negligible. Evidently, path coefficient analysis gave a more clear picture of effects than did the simple correlation analysis. Apis florea on an average visited 1.14+0.23 and 22.78+2.57 umbels and flowers/min, respectively during different hours of the day. Furthermore, the insect pollinated plots produced significantly more seeds with heavier weights than those isolated from insect visits.
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Floral biology of tree fruit rootstocks
153-161.Views:152The modern nursery industry requires seed sources of a high quality and regular quantity year by year. Besides the seed sources of processed cultivars (Bartlett pear, Shipley, Elberta peach) special seed orchards are planted with selected seed trees producing high quality and genetically determined seed (hybrid seed or inbred lines). Seedlings are still the most common commercial source of rootstocks for stone fruits (almond, apricot, peach, plum, prune and walnut). Although clonal rootstocks are spreading, usage of seedlings is still predominant at stone fruits and nuts. For successful seed production and planning of seed orchard the knowledge on floral biology, flower fertility, pollination, blossom time of trees (selected clone or cultivars) used for seed production is essential. In this field very little systematic research was carried out most of the papers were published in the second half of the 20th century. Our mini review gives an overview on the importance of flower fertility in the mating systems applied in seed orchards, and the research results on floral biology of fruit tree rootstocks propagated by seed (Prunus avium, Prunus mahaleb, Prunus armeniaca, Prunus cerasifera, Prunus insititia, Prunus amygdalus, P persica, P amygdalopersica, Pyrus pyraster, Pyrus communis and Pyrus betulifolia) over the last decades.
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Malus taxa and the progenies of Malus floribunda selected in Hungary, as gene sources of resistance breeding
25-28.Views:119One of our objectives in the apple breeding program of the Department of Fruit Science, beside creating new varieties, is to search for new gene sources. After evaluating the disease resistance of Malus taxa available in Hungary, we put the promising selected individuals through further examinations. Their habit and growth vigor was observed, as well as productivity and fruit characteristics were evaluated. Malus fusca seems to be a new, promising gene source in Hungary among the examined taxa. Beside its optimal canopy, growth vigor and fruit characteristics, it has the advantage to be in distant relationship to Malus x domestica, therefore its resistance is based on a different genetic basis. SBG 1 selection of Malus spectabilis can be recommended as a new gene source for resistance breeding. The range of gene sources can further be widened by selected clones of Malus floriblunda (BA I), Malus x zumi (BA) and Malus baccata (SBG 6). An additional value of Malus taxa chosen by us is that they show resistance not only to apple scab, but to powdery mildew as well, and according to our results, they have optimal habit, acceptable productivity and good fruit quality. Nine hybrids were selected from first Malus progenies which proved to be resistant to apple scab and powdery mildew. These are valuable not only as gene sources of breeding, but as pollenizers or ornamental trees, while their decorative fruits can be used in inside decorations and flower arrangements.
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The effect of nectar production to the gathering behaviour of honeybees and to the foraging activity of wild bees at apple flowers
45-57.Views:163Intensity of bee visitation (honeybees and wild bees), foraging behaviour of honeybees and nectar parameters (nectar production, sugar concentration, sugar content in nectars) were inspected at 18 apple cultivars for three consecutive years. Honeybee visitation was calculated to be some 3.07 bee visits at a single apple flower a day but wild bee activity was very low, only some 0.11 wild bee visits per flower per day.
The nectar production (nectar content) of apple flowers was fairly different according to the cultivars and the nectar production (nectar content) of flowers was negatively correlated with the sugar concentration in nectar. Interestingly, at the majority of the inspected 18 cultivars the nectar production has shown minor or no changes in the morning and at the afternoon. The nectar production (nectar content) of flowers clearly encouraged the total bee activity at the inspected cultivars (r = 0.54). Bees visited abundant nectars with greater sugar concentration most intensely than lees abundant nectars with smaller sugar concentration.
Nectar parameters, however, affected the activity of honeybees with different types of gathering behaviour in different way. More intense activity by pollen gatherer and mixed behaviour honeybees was observed at cultivars producing abundant nectar (pollen gatherers: r = 0.65, mixed behaviour: r = 0.79). The activity of pollen gatherer honeybees and of mixed behaviour bees, on the other hand, was negatively correlated to the sugar concentration in nectar (pollen gatherers: r = -0.51, mixed behaviour: r = -0.73). This can be explained by the fact that their behaviour was much more affected by the amount of pollen than by any nectar parameters. Accordingly, "mixed behaviour honeybees" should probably rather be called as "pollen gatherers with nectar load" instead of "nectar gatherers with pollen load", as widely used in literature. The activity of ineffective side worker nectar gatherers was greatly encouraged by the sugar concentration in nectar (p = 0.63), similarly to the pure (top) nectar gatherer honeybees (r = 0.72). There was a negative relationship between the nectar production (nectar content) of flowers and the activity of these behaviour classes (nectar gatherers: r = -0.47, side workers: r = -0.36).
Concluding the findings we can state that the activity of pollen gatherers and mixed behaviour honeybees is strongly encouraged by greater nectar production (greater nectar content) of apple flowers. Their activity, however, is mostly dependent firstly on the amount of pollen. This is the reason why the sugar concentration is in a negative relationship to the activity of pure pollen gatherers and mixed behaviour bee. On the other hand, pure nectar gatherers and side worker nectar gatherers are greatly encouraged by the sugar concentration of apple nectar the amount of nectar was not a definite influence on their activity.
Side worker honeybees occurred at each cultivar inspected, however, their ratio varied widely among cultivars. So we can draw the conclusion that, in contradiction with earlier believes, side worker nectar gathering is a general phenomenon at apple flowers. The activity of side workers depends first of all on the relative position of stamens and petals; however, low sugar concentration of nectars can probably moderate their activity but probably do not affect pollen gatherers and mixed behaviour bees.
Wild bee visitation was very low; the wild bee species observed (Osmia cornuta, Andrena flavipes, Anthophora acervorum, Bombus terrestris, Bombus lapidarius and Halictus simplex) comprised some 3.44 per cent of the total bee visitation at apple flowers only. Wild bee visitation was in a positive correlation with the nectar production (nectar amount) of flowers (r = 0,4) and with the sugar content of nectar (r = 0.46) but it was negatively correlated with the sugar concentration in nectar (r = -0,27).
Our result calls the attention to the importance of nectar parameters in the effective honeybee pollination of apple plantations. Most effective pollinating activity of honeybees can be expected in plantations with cultivars of high nectar production because this feature seem so encourage the activity of those behaviour classes (pure pollen gatherers and mixed behaviour bees) that are the most effective pollinating agents among honeybees.
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Honeybee (Apis mellifera L.) visitation at the flowers of quince cultivars (Cydonia oblonga Mill.)
95-102.Views:146Studies were made on the bee visitation of 6 quince cultivars and on the foraging behaviour of honeybees at quince flowers for 3 consecutive years. The bee visitation was highly intense because both the plantation and its surrounding was overpopulated by honeybee colonies. Some 5.5 bee visits were counted in average at 50 opening quince flowers in 10 minutes and some 9.7 flowers were visited of the 50 ones observed meanwhile. This equals some 7 bee visits per flower per day per in good weather. Bee visitation, however, was variable and it was greatly different in the three consecutive years with fairly favourable weather. Some cultivars tended to be more and others less visited by honeybees than the others but these differences were not consequent at each occasion. No consequent relationship between the weather and the bee visitation of quince trees could be recognised. It was concluded that .other factors were responsible for the variable nature of the bee activity at quince. Most honeybees tended to collect pollen (51.6% in average for the 3 years) and usually much less gathered for nectar only (19.9%), and the rest of them were mixed behaviour foragers gathering for both (28.5%). There were some slight differences in the foraging behaviour of honeybees at some cultivars but these differences were not always consequent in consecutive years. Also the nectar production of flowers failed to affect the bee visitation and the foraging behaviour of honeybees definitely. For the variable nature of bee visitation and bee behaviour at quince flowers, supplementary pollination is needed to achieve as high set of fruits as high is required to a good crop at quince (at least 20-25% because the flower density is low of this fruit tree species). Since the intensity of bee visitation at the flowers is the only reliable estimate of the necessity of supplementary bee pollination further research is needed to explore the relationship between the number of honeybee visits and the consequent fruit set at quince.
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Inheritance of the characters related to flower formation, blooming and fertilisation in apple
63-65.Views:139On the base of observations performed during a period of 20 years the blooming characters-of apple varieties and their progenies the following statements are actual.
In blooming dynamics there was no difference between paternal and maternal effects. In the assignment to blooming time groups, the paternal effect prevailed whereas in the tendency of flower initiation on long shoots maternal parent was more decisive. Varieties as 'Golden Delicious'. 'Jonathan', 'Red Delicious', 'Rome Beauty' and 'Staymared' and their respective, naturally raised mutants did not differ in blooming characters.
The possibility of predicting the relation to blooming time groups of early (July, August) ripening individuals is low, whereas late (September. October) ripening ones have a good chance to be medium late in blooming time.
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Relationship between flowering, fruit setting and environmental factors on consecutive clusters in greenhouse tomato (Lycopersicon lycopersicum (L) Karsten)
111-116.Views:125The main season of greenhouse tomato begins late winter or early spring in the northern Temperate Zone. During this period decisive environmental factors affect flowering and fruit setting.
In the present experiments, progress and dynamics of greenhouse tomato flowering and fruit set were examined in 1999 and 2001 spring. The beginning and the end of flowering and fruit set, the number of flowers and fruits set in each cluster were recorded. Flowering and fruit set characteristics were analysed with respect to the accumulated PAR and temperature were calculated for each cluster. One flower required 31.3 mol M-2 of accumulated PAR and 38 °C of sum temperature as an average for anthesis. One fruit required 27.9 mol m-2 of accumulated PAR and 33.3 °C of sum temperature as an average for fruit setting.
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Prediction infection risk on the basis of weather-related factors and Erwinia amylovora colonization in apple and pear flowers
39-54.Views:156Current infection risk prediction models utilize environmental parameters and field records, but do not take into account the estimated inoculum potential within the orchard. The object of this study was to survey the accuracy of three simple prediction methods under Hungarian climatic conditions, which could easily be used by the farmers. We also tested whether the accuracy of infection risk predictions can be improved by taking into consideration the incidence and/or rate of flower colonization by Erwinia amylovora.
After preliminary investigations in 1999-2001, data concerning the weather-related infection risk were recorded in 5 apple and 1 pear orchards in 2002, and in 12 apple and I pear orchards in 2003. The weather data were processed by the easy-to-use risk assessment models of the mean temperature prediction line (MTL), Smith's Cougarblight 98C and Billing's integrated system (BIS), and by the MaryblytTM 4.3 computer-assisted model for reference. The population size of E. amylovora in the flower samples was estimated within an order of magnitude by PCR.
For all years and orchards tested, Maryblyt indicated 35 days on which there was an acute infection risk. The same days were indicated by all 3 methods in 23 cases (66%), 8 days were indicated by 2 methods (23%) and 4 days were indicated by 1 method only. A similarly good correlation was found for prediction of the date of the first massive infection risk: in 2003, for instance, there was a perfectly consistent prediction by all 4 models in 9 of the 13 participating orchards. A coincidental forecast was provided by 3 of the 4 models in the other 4 orchards.
The results indicate that any of the risk assessment models could provide an increased accuracy of the actual infection risk prediction if combined with an estimation of the incidence of Erwinia amylovora colonization in the open flowers. We found no convincing differences in the size of the epiphytic population in flowers of cultivars possessing high or low susceptibility to Erwinia amylovora.
We conclude that the easy-to-use methods tested could be used by the fanners to recognize weather-related risks, especially when coupled with an estimation of the proportion of the pathogen-infested flowers. This local prediction would provide rapid information (faster than the regional forecast systems) specifically for a given orchard.
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Fruit drop: The role of inner agents and environmental factors in the drop of flowers and fruits
13-23.Views:397The basic conditions of fruit set (synchronic bloom, transfer of pollen, etc.) still do decide definitely the fate of the flower (Cano-Medrano & Darnell, 1998) in spite of the best weather conditions (Stösser, 2002). 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 (Soltész, 1997). There are also basically genetic agents in action. 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.
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Security of growing habits and bud formation of German sour cherry varieties
45-48.Views:180Intensive 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 four 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. -
Spring frost effects on 30 sweet cherries varieties grown in North Italy
33-37.Views:166After a spring frost occurred in second half of March 2008, with temperatures below 0°C for 8 days consecutively and an absolute minimum of -5.5°C, a lot of observations have been made on the sweet cherry flowers damages. In three different orchards “Italian palmetta” trained on grassing ground soil, the percentage of the flowers killed by frost, was detected and recorded considering the different genotypes and flowers height from the ground. Furthermore, in one orchard only it was possible to find relationship between flowering stage and frost damage. The results clearly confirm our previous works about the highest mortality of the flower in the upper part ( > 1.50 m) of the canopy and in the full bloom open flowers. So, in this area, the easiness of agronomic operations, like pruning and, especially, fruit harvest, due to the crown proximity to the ground, is cancelled by the frequency of spring frost.
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Some structural characteristics of the flowers of apple cultivars with different susceptibilty to fire blight
21-23.Views:112Several morphological characters of the hypanthium (size and form of the surface, the shape of the hypanthium) and anatomical traits (number and pattern of stomata) of apple cultivars (Malus domestica L.) with different susceptibility to fire blight were studied. The size of hypantium surface was calculated by modelling the hypanthium with a truncated cone. Three types of hypanthium surface form have been revealed: straight, convex and a complex "shouldered" one. The angle between the style and the wall of the hypanthium was narrow or wide. The stomata on the hypanthium surface can be arranged in a zone in the middle third of the hypanthium or dispersed more or less evenly. The number of stomata/flower substantially differed among the cultivars examined. The highest stomata number was detected in the flowers of the tolerant cultivar (Freedom)
No single characteristics of the hypanthium could convincingly be correlated with susceptibility to fire blight. We suggest, however, that combination of morphological properties that sustain moist environment in the hypanthium contribute to susceptibility.
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The effect of spring frosts on the nectar production and the bee visitation of fruit trees
86-89.Views:150Fruit tree species suffered very strong spring frosts in 1997 in Hungary. This caused partial or total damages at buds and flowers depending on site and time of blooming. It was demonstrated at a number of experiments that frost and cold weather also strongly affected the nectar production of surviving flowers. No or very little amount of nectar was measured in flowers first of all of early blooming fruit tree species (apricot) but also of pear and apple in some places. In spite of this fact intensive honeybee visitation was detected in the flowers of fruit trees that suffered partial frost damage only at those sites where honeybee colonies were placed in or at the experimental plantations and the lack of sufficient amount of nectar did not affected bee behaviour seriously on fruit flowers. This means that bad nectar production failed to affect bee visitation of fruit trees definitely. The reason for this was the fact that not only fruit trees but another early bee plants (wild plants, too) suffered frost damage. Accordingly, in lack of forage bees intensively searched for food at blooming fruit trees with some living flowers. Consequently, there was an acceptable yield at those plantations where bud and flower damage was not complete. Accordingly, intensive bee visitation (that is moving additional bee colonies to overpopulate fruit orchards with honeybees) can be an effective tool to decrease or eliminate the detrimental effect of spring frost on the yield of fruit trees where bud or fruit damage is not too high.
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Colour stability of the flowers in some modern rose varieties in Hungary
61-66.Views:149A variety trial has been carried out to study the colour changing — colour stability of the flowers of some modern roses, especially of Hungarian varieties. 100 floribundas and polyanthas were observed. Colours of the petal surface were examined at three fenological stages of the flowers: at the bud, at the young open flowers and at the aged open flower stages. The colour difference was described in HLS standard. Our work shows that valuable Hungarian varieties can be found in both studied classes, but more floribundas bred in Hungary had good colour stability than polyanthas. The best Hungarian floribundas were 'Pest' and 'Remenyik Sándor emléke', although 'Regen', `Szent Lász1ó emléke' and 'Szabó Dezső emléke' were quite good. The best Western-European floribunda rose was 'Perneille Poulsen'. Their colour stability was reliable in different situations. Colour changing of the two best varieties was almost unperceivable from the bud to the young petals and from the young to the aged petals. In the polyantha class there was only one perfect variety: the Czech `Cs1 Cerveny Kriz'. The 'Fairy Damsel' was almost excellent as well. The best Hungarian polyanthas were `Domokos Pál Péter emléke' and 'Savaria'.
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Exotic woody plants inclining to escape in the Buda Arboretum under strong urban effect in Budapest
93-97.Views:129The Buda Arboretum of the Szent István University is situated in the western-middle part of the city of Budapest. It contains 1640 taxa of woody plants on an area of 7.5 ha. The sheltered position and the urban micro- and meso-climate is favourable for warm-loving, even subtropical plants, of which many species not simply stay alive, but flower, bear fruits and are spreading by seedlings in suitable spots. These instances call our attention to the possibilities that urban climate offers for landscapers, but also to over 110 species, which can be garden escapes in the future. Full list of plants, which tend to escape in the Arboretum is given in the paper.
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Effect of intensity of bee visitation and the foraging behaviour of honeybees on the fruit set and yield of apple (Malus domestica Borkh.)
31-39.Views:134Based on the results of our experiments, both the relative and the effective intensity of bee visitation were rather different depending on the cultivars as well as the time of the day. While it varied between relatively extreme values (40-80%) in the morning for the varieties examined, there were much smaller differences between the intensity of bee visitation at the afternoon, because the relative bee visitation attained 70-90% at each cultivar. These results showed that the differences arising from intensity of bee visitation of different cultivars should be taken into consideration more carefully in the morning in orchard planning and in estimating the number of honeybee colonies required.
The results showed that the greatest percentage of fruit set and the highest number of viable seeds per fruit were measured on branches of those cultivars that were most frequently visited by pure pollen gatherer bees as well as by bees collecting both nectar and pollen (mixed behaviour). The effect of pure pollen gatherers and of bees with mixed behaviour was highly significant from the statistical point of view on the fruit set and the number of viable seeds per fruit.
Those bees that were sucking nectar only from apple flowers did not proved to be effective pollinators at all. Relationship between their number and the fruit set as well as the number of viable seed per fruit were not significant because the coefficient of correlation was close to nil.
The ratio of side worker nectar gatherers was negatively correlated with the fruit set and the seed content of fruits of apple cultivars examined at both of our experimental sites, at Mosonmagyaróvár and Feketeerdő as well. The presence of side worker nectar gatherers resulted in higher decrease of fruit set and seed content of fruits at Feketeerd6 than at Mosonmagyaróvár, especially in the morning.
The effect of flower visiting intensity by other pollinating insects was found to be fairly variable according to the time of the day. In the morning they had no effect on the fruit set as well as on the seed content of fruits either at Mosonmagyaróvár or at Feketeerdo. However, at the afternoon, when their intensity was greater, the correlation was a bit stronger.