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Effect of life cycle on the production of mullein (Verbascum phlomoides L.)
123-125.Views:156Aim of the present investigations was the optimalization of the production of the annual cultivar `Napfény' of Verlxiscum phlomoides L. Quantitative data on morphology (growth, leaf and flower size, branching) yield and content of active materials (mucilages, flavonoids) were studied at six sowing times.
We established, that sowing time may be one basic factor in the production of the annual variety. The major yield was obtained by sowing either late autumn (end of October) or early spring (middle March). At these plots the fresh mass of the flowers was 257-288 g/plant, the drug mass 28-29 g/plant, by 45-70% more than that of the mean of other treatments.
It was established, that under optimal cultivation conditions the annual form of mullein may reach higher individual yields than the plants of the indigenous wild growing population.
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Evaluation of vermicompost application and stress of dehydration on mullein medicinal plants
69-77.Views:114The use of organic fertilizers is one of the suitable solutions in the organic production of medicinal plants due to its good effect in improving soil properties, reducing environmental effects, and better plant growth. To investigate the effect of vermicompost organic fertilizer application and water stress on some morphological and physiological traits of the Mullein medicinal plant, research was conducted at Isfahan Azad University in the form of split plots in the form of a randomized complete block design with 4 replications. The test factors included the application of vermicompost organic fertilizer at three levels of 0, 4, and 8 kg per square meter of soil and water stress at two levels of normal irrigation and irrigation at the time of 50% of the soil's agricultural capacity as the main treatment in research farm conditions. The results of the experiment showed that the application of vermicompost organic fertilizer and water stress improved the morphological and physiological characteristics of the Mullein medicinal plant compared to the control, i.e. no application of organic fertilizers. The results showed that the highest number of secondary branches, number of flowers of the secondary stem, diameter of flowering stem, the diameter of flower, and fresh weight of shoot in the Mullein medicinal plant were obtained by applying vermicompost organic fertilizer at the rate of 4 and 8 kg of soil. The application of vermicompost organic fertilizer at the rate of 8 kg in the soil increased flavonoids compared to the non-use of vermicompost treatment. However, to improve the vegetative growth and increase the reproductive efficiency of the Mullein plant and reduce production costs, the use of vermicompost organic fertilizer is recommended at the rate of 4 and 8 kg of soil, respectively.
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New sweet cherry cultivars in intensive plantings
13-16.Views:343The study took place in the largest sweet cherry plantation in West Hungary. The purpose has been the identification of those varieties, which will be suitable for intense cultivation, early fruiting and excellent fruit quality, moreover, the selection of the optimal phytotechnical procedures. At the same time, scion-rootstock combinations have been tested also from the point of view of growing intensity and fruiting in high-density plantation. The dense planting is induced to start fruiting early and yield regularly by special methods.Yielding was stimulated by maintaining the balance of vegetative-generative growth by binding the shoots, by summer pruning, by cuts on the trunk and root pruning. Best experiences have been found in yield and quality in the following varieties: Canada Giant, Carmen, Firm Red, Giant Red, Katalin, Kordia, Regina. Dense planting has been feasible also on vigorous rootstock, like P. mahaleb. Dwarfing rootstocks like P-HL-A, Gisela 6, accelerate the formation of flower buds and yielding earlier with fruits of adequate size. ‘Firm Red’ and ‘Giant Red’ excelled with their large fruit (>27 mm diameter) in all combinations, thus being promising under Hungarian conditions.
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Scheduling of ornamental plant production
76-86.Views:130The production of ornamental plants represents an important branch of our horticulture. The growing area is relatively small (round 2800 ha), the production value, however, a rather large. Notwithstanding, its financial balance is inactive because the demand surpasses the supply copiously.
The most popular plants are as follows: carnation, gerbera, rose, bulbous flowers, chrysanthemum, other cutflowers, cutgreens and Gypsophyla — their total production value makes up to Ft 8-9 billion. The area of ornamental nurseries — about 800-900 ha — is to be found mostly on the western part of our country.
Our accession to the EU will have undoubtedly an impact on our ornamental plant production. We must take into account, that in greenhouse production the specialization extends all over the world, field production over a limited region. Our chances will not deteriorate by joining the EU. The buyer — chiefly because of ecological purposes — will prefer the domestic product to the foreign one. By the way, our products will be competitive, as far as quality or price is concerned, with those of western Europe. Last but not least, we may hope a greater saleability of home-bred, special varieties and cultivars, the so-called "hungaricums", both in the domestic as well as export markets. It is anticipated that we will have a good turnover with potted ornamental plants and flower seedlings. Our nursery products will become marketable too.
To exploit the opportunity, of course, the necessary conditions are to be created. First of all, we need development in research, with special regard to breeding, at the same time in education, in extension service, in the training of experts, on a high level. Some tasks can be solved, no doubt by improvement of the organisation within the branch. At the same time the state subsidy is indispensable in order to promote both the technical and the research activities. State subsidy is also necessary to build up more advantageous conditions of sales like in some foreign countries (e.g. the Netherlands).
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Nutrient demand of stone fruits
19-23.Views:143Effects 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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Effect of Foliar Nutrition on Post-Harvest of Onion Seed under Sandy Soil and Saline Irrigation Water Conditions
85-92Views:232Foliar application has been determined to be an effective nutrients delivery strategy in vegetable and fruits. The enhancement of vegetable and fruit yields affected by foliar nutrients application has been recognized in previously conducted studies with perennial tree crops. The efficiency of foliar nutrition is dependent on soil, climate, fertilizer and the amount of nitrogen used. There is no sufficient information concerning cooperation of foliar nutrition with all nutrients form as well as the rates of these nutrients fertilization in vegetable
and fruit crops. Two successive winter seasons of 2008/2009 and 2009/2010 were conducted under sandy soil conditions to study the effect of spraying with 12 commercial compounds on inflorescences diameter, flower stalk length, number of seed stem /plant, weight of 1000 seed, germination percentage, seed yield, moisture content, catalase , peroxidase activity and malondialdehyde content of onion seeds. The plants
sprayed with union Zn, union Mn, union feer, shams k, elga 600, boron, and amino x had the highest vegetative growth parameter, germination percent and enzyme activity. The plants sprayed with union Zn, union feer, shams K, magnesium, caboron, hummer and amino X had the highest seed yield ha-1. The seeds were stored for one year to study the effect of different commercial compounds and storage temperatures on germination, moisture content and change in antioxidant enzymes activities of onion seeds during the storage period. Storage at cold temperature showed higher germination percent, moisture content and lower malondialdehyde content than storage at room temperature. The treatment with union Zn, union feer, union Mn, boron, elga 600, caboron, amica, hummer and amino x had the highest germination percent. -
Fruit drop: I. Specific characteristics and varietal properties of fruit drop
59-67.Views:410The 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.
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The effect of the limitation of insect pollination period on the fruit set and yield of quince cultivars (Cydonia oblonga Mill.)
103-108.Views:267The effect of the partial and/or complete limitation of the insect (bee) pollination period was studied in three consecutive years at 6 quince cultivars. Quince is greatly sensitive to the limitation. Complete limitation of insect pollination resulted in no yield and also a partial limitation of the insect pollination period (exclusion of the bees at the first or at the second half of the blooming) depressed the final set and the yield by 60-70% at least or more, sometimes down to no yield. No real correlation was found between the mean mass of fruits and the fruit set. The mass of fruit seems to be rather a character of the cultivars. A loose but significant correlation was established between the intensity of honeybee visitation and the consequent yield of quince. As much as some 4-5 and 8-10 honeybee visits are needed a day on one flower to achieve the required optimal fruit set that has been declared to be 20-25% for quince in the literature. These are extremely high bee visitation figures, accordingly, no doubt the commercial quince plantations require much higher number of honeybee colonies than other temperate zone fruit tree species to supplementary pollination
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Comparative analysis of sweet cherry cultivars on their ecological and biological indicators
14-33.Views:155Sweet cherries are slightly more demanding than sour cherries. It is grown in warmer areas around the world. The relative ecological values obtained for the varieties obtained by extensive data collection differ slightly from the leading descriptions. Warm and demanding. The woody parts tolerate the cool of the winter quite well, the flower buds are damaged by the spring frosts. Its water demand is medium, in the case of 550 mm of annual rainfall, it adorns well on loose soils with good nutrient supply. Airy ground, neutral soil (pH 5.5-7.5) is optimal, but not suitable for areas with strongly calcareous, stagnant, stagnant groundwater. From the start of ripening, sudden rainfall, stormy winds and birds can cause great damage. Highlighting the world’s leading varieties in the study (Bing, Rainier, Chelan, Van and Burlat) (Iezzoni et al., 1991, Faust & Surányi, 1997) - according to relative ecological and biological values, the most popular cherries are mainly they differed from the other varieties based on TB and KB. Open pollination and with it, the productivity of the varieties exceeded the overall variety average precisely because of the breeding objectives. Certainly, the analysis of historical varieties, the oldest landscape and local varieties based on relative ecological and biological values can help further pomological-ecological research.
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Changes in Some Quality Criteria During Controlled Atmosphere (CA) Storage of Peaches
58-61.Views:120Intensive 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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Growing greenhouse cut flower in hydro-culture
37-39.Views:156The importance of hydro-cultural growing is significantly increasing.We have been dealing with the hydro-cultural growing of cut flowers at the Department of Ornamental Plant Growing and Maintenance of Gardens at the College Faculty of Horticulture at Kecskemét College since 1988.We started our experiments by growing carnation in growing establishment without soil then we introduced other species of cut flowers and potted ornamental plants into our research work.
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Inheritance of blooming time in walnut, with regard to the property of reproductional autoregulation of species
118-122.Views:131A great number of crosses have been made with Hungarian and foreign varieties as partners to breed improved varieties. This species shows a particular trait, namely the autoregulation of fruit set, which affects considerably the productivity of commercial orchards. Thus the inheritance of the blooming time of the male and female flowers has been explored for several years in the progenies.
It has been stated that
- the feature of the partners does not turn up predictably in the progeny,
- it is most important to take into consideration the blooming time class of both, male and female flowers in planning associations of varieties for commercial orchards.
- in years of irregular spring weather the stability of the blooming time of the variety or in other words the deviation of the actual blooming time of variety from its characteristic blooming-time class is also very important.
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Influence of foliar nutrition on apple production
15-18.Views:132On the basis of different experiments the technology of intensive foliar nutrition was studied in apple orchards in the period from 1996 until 2000. Yearly apple nutrition programs based on soil analyses. The foliar nutrition program was prepared in accordance with the soil, fruit analyses and climatic conditions. If needed, certain improvements were made according to the analyses of leaves and precipitation in the current year. The richness of the soil and ratios between individual nutrients gradually improved. The foliar nutrition influenced the yield quantity, quality and flower bud differentiation. The yield was doubled and the mean of five years reached 70 tons per hectare. In spite of high yields there were no problems with alternative bearing. The analyses of soluble solids, firmness, fructose, glucose, sucrose, malic acid, citric acid in the fruits and mineral soil composition indicated that the produced fruits were of high quality despite greater yields.
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Comparison of honeybee behaviour in blooming fruit plantations
147-151.Views:275Field observations were made on the fl ower visiting behaviour of honeybee foragers in commercial fruit plantations of apricot, Japanese plums, sour cherry, apple and pear. The number of inspected cultivars was 18. The intensity of fl ower visiting by honey bees was markedly different when data of different fruit species are compared. Most intense bee activity was registered on the Japanese plums, somewhat less on apricots, the intensity diminished signifi cantly with apples and pears. Our data presented on the honeybee visitation of Japanese plums can be regarded as new fi nding because no information has been available so far on the relative attractiveness of this fruit species compared to European fruit tree species. Japanese plums were somewhat more attractive to honeybees than apricot and much more attractive than sour cherry, apple and pear. The behaviour of honeybees as visiting the blooming trees displayed specifi c differences according to the fruit species (apricot, sour cherry, pear), which coincide largely with earlier results. It is notable that the fl ower visiting behaviour of honeybees on Japanese plums has been found to be fairly similar to the same on European plums.
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The role of meteorological variables of blossoming and ripening within the tendency of qualitative indexes of sour cherry
7-10.Views:244We analyzed the relationship to sour cherry quality parameters of average temperature, maximum temperature, minimum
temperature, night and day-time temperature, precipitation and climatic water balance variables. Three cultivars of sour cherry were included
in the selection: “Debreceni bôtermô”, “Kántorjánosi”, and “Újfehértói fürtös”.We conducted regression analyzes on the three varieties, but
present only those that proved to be the best fit.We couldn’t find any significant differences in the weather tolerance of the varieties. The data
base of sour cherry quality parameters covers the 1998 to 2008 intervals. The researched parameters were the following: dry matter content
(%), sugar content (%), C-vitamin (mg), total acid content (%). Maximum temperature, the difference of night and day-time temperature and
minimum temperature all have a significant correlation with the investigated quality parameters of sour cherry. Minimum temperature shows
a quadratic relationship with sugar content, while night and day-time temperature differences show the same with dry matter content. The
other weather parameters had a linear correlation with the quality parameters of sour cherry. The research results show that an increasing
amount of precipitation causes decreasing tendency in total acid content of sour cherry, so that increasing temperature has a positive influence
on total acid content. Big differences in night and day-time temperature also has positive effects on the dry matter and sugar content of sour
cherry while the amount of precipitation has a negative effect. High minimum temperatures cause decreasing sugar content respiratory energy
losses are significant if dawn temperatures do not drop considerably.A more favourable climatic water balance has a positive effect on vitamin
C content in cases of a large negative water balance, vitamin C content is generally low. -
Incompatibility studies of Hungarian sweet cherry (Prunus avium L.) cultivars by traditional test crossings
43-47.Views:120Cross-incompatibility is a common phenomenon between various sweet cherry (Prunus avium L.) cultivars. Traditionally, choosing cross-compatible cultivar pairs is based on test crossings in the field.
There is a lack of information about fertility relations of novel Hungarian sweet cherry cultivars and selections. We have studied cross-incompatibility in 42 sweet cherry cultivar pairs by test-crossings in the field. Out of those, 3 combinations showed incompatibility and 15 pairs were compatible.
Test-crossing results proved that with the knowledge of S-allele constitution of Hungarian cultivars incompatible cultivar pairs are recognised in practice reliably. However, we assume that in sterility not only the S-gene system, but other factors (e.g. abnormal development of pollen or flower) also occur, therefore, their examination would be needed.
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Field trials with non-bactericide products to control fire blight in apple orchards
55-60.Views:137Recently, novel strategies and chemical agents for prophylactic protection against the bacterial (Erwinia amylovora) disease fire blight are being sought. Resistance-inducing compounds, such as prohexadione-Ca represent promising alternatives. Prohexadione-Ca is the active ingredient of the bioregulator Regalis, currently being introduced in several European countries and overseas. Another product used in this study was Biomit Plussz, a leaf fertiliser providing harmonic supply of nutrient elements, the complete supply is assumed to improve the tolerance against diseases.
Treatments' effects of both of these products were compared to the effectiveness of treatments with antibiotics repeated twice, three or four times a season.
In the years of 2001 and 2002, the effectiveness of both Regalis and Biomit Plussz in reduction of incidence of shoot blight was similar, or proved to be superior to the check treatments consisting of repeated sprayings of antibiotics. Last year (2003) treatments of streptomycin resulted — although within the same magnitude — in a somewhat better control of shoot blight than sprayings with the other compounds.
As regards severity of blossom blight, inconsistent results were recorded concerning both Regalis and Biomit Plussz.
In general, prohexadione-Ca is less efficient for controlling flower infection by E. amylovora as compared to shoot infections, since successful prophylactic treatments are difficult to carry out early in the season. The highest effectiveness in fire blight management can, therefore, be achieved by using prohexadione-Ca (as preventive protection) in combination with streptomycin or other suitable antibiotics (as curative protection).
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Floral attractivity of pear cultivar 'Cinderi'
102-109.Views:148The regularities of primary attractivity have been studied at the pear cultivar `Cinderi' for two years. Nectar quickly evaporates from the totally open nectary surface of pear flowers exposed to environmental effects, and the rhythmicity of nectar secretion can be determined with difficulty. Flowers do not function according to a unified endogenous rhythm, the whole tree becomes continuously attractive for insects, since it attracts insects on more occasions during the day with some of its flowers. During the warm afternoon hours there is usually no measurable nectar production. Pollen shedding is most intensive in the afternoon hours. Pear flowers produce little and diluted nectar, which often does not come up to apicultural expectations. The age of the flower does not significantly affect the quantity and refraction of nectar. The flowers of pear cv. ‘Cinderi' are delayed homogamous.
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Reactions of different plant organs of pear cultivars to Erwinia amylovora infection
17-21.Views:137Research project has been initiated in 1999 with the aim of evaluating the degree of susceptibility/resistance of pear cultivars grown in Hungary to fire blight disease caused by Erwinia amylovora. The recently selected promising cultivars were also examined. Inoculation experiments were conducted in controlled greenhouse conditions because of quarantine regulations in Hungary. Following the disease process, development of symptoms of plant organs (shoots, flower parts, fruits) was observed. Suspension of two E. amylovora strains (Ea 21, Ea 23) isolated from pear was used in a mixture (5x108 cells x m1-1) for the inoculation. Twenty-six pear cultivars were examined and grouped into four categories: low susceptibility, moderately susceptible, susceptible and very susceptible. Most of the cultivars were susceptible or very susceptible while some promising 'Eldorado', 'Harrow Delight' and `Hosui' showed low susceptibility.
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Effect of hail protecting nets on the quality of apples
77-80.Views:249Today, successful fruit growing depends largely on the security of production. Among the technological elements of a secure growing system, the use of hail protection nets serves special attention. Components of security are the regularity, conspicuous large yields with excellent quality, which determine the prices and profitability as well (Szabó et al., 2010). In the European Union, most of the apple growing countries produce higher yields by 10-20% than Hungary. The conditions of better yields are partly due to a more favourable ecological milieu, partly to more developed technologies and serious discipline of the operations. Our own competitiveness could be developed first of all in those moments. As a consequence of global climatic changes, excesses of weather, i.e. hail-storms became more frequent. Different methods of protection against hail are developed abroad but also in Hungary. The examination of effects of the hail protection nets compared with the check without nets has been the purpose of our experiments. The growing system was the intensive one with high planting densities. Fruits of the two subsequent years have been compared as grown with and without hail protective nets. It turned out that in one season when shoot growth was stimulated, the shadowing effect of the net increased in addition the growth and at the same time braked the differentiation of flower buds, which exerted negative effects on yield of the next year. Let alone this phenomenon, the quality of fruits was not influenced by the hail protection net.
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Histological studies on small bulb flower crops
83-85.Views:135Investigations were done in order to obtain more information on the histological structure of bulbs of Allium moly, Allium sphaerocephalon, Muscari armeniacum and corms of Crocus sativus. While starch grain were found in the bulb of Muscari armeniacum, fluid nutrient content were shown in Allium species. Narrow and fleshy scales were found in the bulbs of Muscari. Histological characteristics of Allium moly and Allium sphaerocephalon showed a closer relationship with corms than with the bulbs. To clarify this question, further investigations are needed (Bailey, 1942; Larson, 1980).
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Nectar production of quince (Cydonia oblonga Mill.) cultivars
87-94.Views:308Nectar production of six quince cultivars were measured during three consecutive years. The nectar production of quince can be regarded to be small compared to other temperate zone fruit tree species since quince flowers contained 1.07 ± 0.06 mg of nectar in average. The extreme values, however, ranged between 0.1 and 7.3 mg/flower and this indicated that the nectar production was highly variable. The distribution of the nectar production was definitely skew because low values were definitely much more frequent than the highest ones. Our findings do not corroborate the earlier statements on the high sugar concentration of quince nectar. We found some 21-27% sugar in average, only. The normal distribution of the sugar concentration also indicates that the typical sugar concentration may be between 20-30%. Accordingly, the sugar concentration of quince nectar is rather low compared to other temperate zone fruit tree species (except pear). There was a significant negative correlation between the amount of nectar and its sugar concentration in quince flowers in all of the three years of the study (r= -0.51, n=37, p<0.02 in 1996, r= -0.57, n=28, p<0.1 in 1997, r= -0.35, n=9 I, p<0.001 in 1998). No definite difference was established between the nectar production of quince cultivars. Nevertheless, one cultivar tended to produce less and two other ones produced somewhat more nectar in average than the rest of the 6 cvs investigated but the extreme values of nectar production of cultivars overlapped in most cages.
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Seasonality of weather and phenology of reproductive organs of flower of sour cherry cultivars in Hungarian climatic conditions
75-80.Views:212Sour cherry (Prunus cerasus L.) is one of the most important fruit crop grown in Hungary, The flowering phenology and pollen shedding/stigma viability ratio, in an effort to elucidate the reproductive phenology of nine economically important sour cherry cultivars (Érdi bőtermő, Debreceni bőtermő, Csengődi, Kántorjánosi 3. Pándy 279. Úfehértói fürtös, Petri, Éva, and Oblacsinszka) all widespread in the Hungary, was studied at Újfehertó climatic condition. The main aims were to investigate how possible environmental cues influence timing and development of phenophases and whether different cultivars have different seasonal responses to these cues. Likely effects of climatic changes on phenological development patterns were also considered. Our results revealed 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 maximum 3 days difference in blooming length of different direction 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 tree. The pollen shedding period and stigma viability ratio was well synchronous. Pollen shedding phenomenon occurred in the range limitation of secretary activity of stigmas in all five cultivars. Distribution of pollen shedding over the secretary activity of stigmas is almost good. In all five cultivars maximum pollen shedding occurred about the high temperature part of the day.
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Prolonging the vase life of cut Carnation 'GIOKO' by using different chemicals
65-68.Views:187Cut flowers of Dianthus caryophyllus L. cv. GIOKO were treated with different concentrations of sucrose and in combination with 1methylcyclopropene (1-MCP) to compare the effect of these treatments with floral preservative (`Spring') on the longevity of flowers. Distilled water was used for preparing all solutions. The control flowers were held in distilled water. Clorox at 2 mL- I was added to all treatments containing sucrose and it was also applied as a separate treatment. The vase life of cut carnations was significantly prolonged due to the use of chemical treatments, as compared to the untreated control. The longest vase life (18.33 days) was obtained by using 1-MCP 0.5 g m-3 for 6 h treatment. All concentrations of sucrose had a positive effect on flower diameter. The best treatment in this respect was 1 -MCP with 30 gL-I sucrose. 1-MCP treatment significantly increased the chlorophyll content, as compared to the control or the "Spring" treatment. The highest values in this respect were obtained by 1 -MCP treatment alone or with the lowest level of sucrose. The effect of these treatments on the pH of solutions is discussed.
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Bee pollination and association of apricot varieties
20-24.Views:221Apricot yields are highly variable according to the season. The variation is caused mainly by the adversities during the critical processes of floral biology, i.e. blooming and fertilisation. On the basis of information concerning blooming time and mutual compatibility relations of apricot varieties a system of securing regular and adequate yields has been developed.
Winter frosts of the continental type are well tolerated by most of the apricots, however, after the end of rest period, flower buds are loosing frost tolerance, 'rapidly.
Being one of the fruit species blooming earliest during the early spring, apricot start to bloom in Hungary around the end of March or early April as a mean of many years, but it also happened, exceptionally that apricot started to bloom at February 20 (at Letenye South Hungary). The early season, exposes the floral organs to frost injuries. As a consequence, apricot orchards on the Great Plain produce low yields in 3 years, intermediate yields in other 3 years out of a ten-year-period.
Moreover, weather conditions during the blooming period are often unfavourable for pollination. Cool, windy and rainy weather prevents the flight of insects and on the other hand, warm spells shorten the blooming process, nectarines and stigmata get dry and the female gametes loose viability before effective pollination occurres.
The fertility of individual cultivars are meeting different obstacles. Apricot cultivars differ greatly in the rate of flowers bearing underdeveloped pistils, which may attain even 60% (e.g. Orangered). New commercial cultivars are often self-incompatible. Local varieties of that type in Hungary are the „óriás" varieties (e.g. Ceglédi óriás, Szegedi mammut), and the new hybrid Ceglédi Piroska. Many of the cultivars are variable in their self-fertility (partially self-fertile): Budapest, Harmat, Korai piros, Mandulakajszi.
Inter-incompatibility is also known in apricots. The „óriás " varieties do not fertilise each other. During the growth of fruits, cool spells (2-4 °C) caused severe fruit shed in Ceglédi óriás.
Apricot flowers produce pollen and nectar at average rates related to other fruit species, thus bees are attracted sufficiently. Bee visits are very variable according to growing site and season. Most of the bees are pollen gatherers but sometimes nectar suckers are in majority. Bee pollination is necessary not only for the self-incompatible varieties but also to enhance the yield of self-fertile varieties.
Taking the blooming and fertility relations of the cultivars into account, plantations should not exceed two rows to a particular self-incompatible varieties, and possibly two different polliniser varieties are suggested to be planted as flanking the block in question.
In commercial plantations 2 to 4 bee colonies per hectare are proposed to move for the whole blooming period.