Floral biology and fertility in peaches (Review article)

Results in table beet breeding (Review)

As it well known the decrease of biodiversity is a large problem all over the world. In case of medicinal plants, where the huge majority of drugs are collected from natural ecosystems, the sustainable, utilization of the populations and reservation of their gene-pools has an increased interest.

In Hungary, the major background of 'in situ' reservation of medicinal plant species, their natural plant associations and ecosystems is the official protection by law. Successful examples are known for the controlled utilization of medicinal and aromatic plant species grown in protected areas. Assuring the naturally occuring high degree of biological and chemical diversity of species is a special task in this field: only maintenance of valuable intraspecific races can form the real genetic basis of natural biologically active compounds.

Maintenance of chemotaxonomical gardens and gene bank collections (seed banks, tissue banks) as 'ex situ' methods of reservation is carried out on an extended range in Hungary. As the required information on storage and maintenance of many medicinal and aromatic plant species is yet missing, exhaustive research is carried out at both genebanks in Hungary, which are specialized for medicinal plant reservation (RIMAP- Budakalász, SZIU- Budapest).

Beside the static conservation methods, 'quasi-production systems' are intended to assure an up-to-date and economically possible way of dynamic reservation with sustainable utilization.

During the winter dormancy period of 1998-99, the differentiation process of xylem and the formation of annual and pseudo-annual growth rings was studied in sections of the central stem of Thuja orientalis of different age (1-14 year old), starting from the top (the tip of leader shoot) towards the bottom. In the apical 1-2 cm portion of the one year-old leader shoot, only the protoxylem was formed by the end of vegetation. The protoxylem elements appeared first in 6 bundles than gradually merged into 2 semiquadrangular (triangular) bands (each containing 3 protoxylem bundels) around the pith. In this stem portion, the pith was cross-formed first and became gradually flattened at the lower stem parts, following the generally flattened shape of the stem and the respective facial and marginal position of leaves. A continuous xylem ring (with formation of metaxylem elements) apeared 3-5 cm below the shoot tip. In fact, it was the stem part where a "real" annual ring was formed by the end of vegetation. The first pseudo-annual rings were observed 16 cm below the top. The "regular" annual rings were completely continuous all around the stem, consisted of strongly flattened in radial direction thick-walled latewood tracheids and had a distinct border (demarcation line) at the end of the year. The "pseudo-annual" rings formed incomplete dark rings or semicircular bands within the earlywood. They were composed of tracheids with thick cell walls but somewhat wider radial diameter than those of the "real" annual rings, and the border between their outside margin and the next earlywood was less distinct.

In the xylem of two year old stem portion, the innermost central annual ring appeared not at the transition zone between the current and the former years of growth, but about 2 cm lower. Above that, only the thick-walled bundles of the former years protoxylem were found. Down the stem, the older sections showed similar features: the next annual ring appeared always somewhat lower than the borderzone of the given and the former years growth. The "pseudoannual" rings (or more correctly the growth rings) continued regularly to appear in the lower (older) sections of the stem as well. They were found untill the age of up to 14 years (the bottom of the studied plants). Their number was 3-4 per year first, than (from the 5th annual ring counted from the centre) decreased to 3,2,1, and in the youngest outer part of the xylem there was no pseudo-annual ring at all. The development of pseudo-annual rings was usually more marked on the thicker (more branched) than on the thinner side of stem. Stems older than 14 years were not studied.

The tissue structure of the vegetative organs of strawberry (root, rhizome, stolon, leaf) is discussed in this paper. The authors stated that the root structure described by Muromcev (1969) and Naumann-Seip (1989) develops further from the primary structure. It grows secondarily and the transport tissue becomes continuous having ring shape. In the primary cortex of the rhizome periderm like tissue differentiates, but according to the examinations up to now, it does not take over the role of the exodermis. The exodermis is phloboran filled primary cortex tissue with 3-4 cell rows under the rhizodermis. The development of the transport tissue of the petiole is also a new recognition. In the lower third of the petiole the transport tissue consists of 3 collaterally compound vascular bundles. In the middle third there are 5 bundles because of the separation of the central bundle and in the upper third of the petiole 7 bundles can be observed because of the ramification of the outside bundles. Therefore attention must be taken also in the case of other plants at making sections. There might be confusions in the results of the examinations if the number of bundles increases in the petiole. The tissue structure might vary depending on the origin of the tissue segment.

The palisade parenchyma of the leaf blade has two layers and it is wider than the spongy parenchyma. Among the 5-6-angular cells of the upper epidermis do not develop stomata while in the lower epidermis there are a fairly lot of them.

In this paper we report the establishment methods of a rapidly growing callus culture of Phaseolus vulgaris bean as well as the conditions required for a high level of transient gene expression using Agrobacterium-mediated transformation. A vector is containing both the lindan-resistance gene as a selectable marker, and GUS gene as a screenable marker. By using hypocotyl explant and vertical culture on B5 medium supplemented with 1 mg/1 kinetin- and 2,4-D 2 mg/1 and subcultured every 3-4 weeks, we can recommend to get a good and much callus from bean. This will help in introducing foreign DNA into callus cells. One strain of Agrobacterium carrying plasmid as vector for introducing foreign DNA into plant cells was used. At different concentrations of lindan; 3, 4 and 4.5 mg/I, the transformed Maxidor callus survived and grew over a period of 6 month and subcultured every 3-4 weeks, but the control callus died. Callus were assayed for GUS activity to confirm the expression of the GUS gene using the histochemical assay test. The GUS gene was also correctly expressed in callus cultures grown on 4mg/I lindan-selected medium, the typical blue colour in the histochemical assay using the X-gluc as substrate. But the control, non-transformed callus was not able to grow in the presence of lindan, neither showed a positive reaction in the in vitro assays.

Shoot multiplication responses of rootstocks cvs. M.26, MM.106 and JTE-H to different concentration of BA, BAR and IBA in eight various combinations were tested on MS-medium. The effect of hormones depended on genotype, type of cytokinin and interaction of cytokinin and auxin. Shoot multiplication was significantly enhanced with the use of BAR as cytokinin. High multiplication rate could be achieved in cvs. M.26, MM.106 and JTE-H: 7.7, 6.9 and 9.9 shoots per explant, respectively.

Factors affecting rhizogenesis in vitro and acclimatisation of three rootstocks of cherry, i.e. Mahaleb, Maxma-14 and Weiroot -10 were investigated.

Rooting was easily achieved within 2-4 weeks on MS-based liquid or agar-gelled media containing auxins IBA at conc. 0.49 or 2.45 pM or NAA at conc. of 0.49 pM. On liquid media with 2.45 pM IBA, a maximum rooting efficiency of 95-100% was obtained. However, high concentrations of auxin delayed the time of root initiation for 3-5 days.

Rooted plantlets were transplanted into pots with a mixture of 3:1 (v/v) peat:perlite and acclimatised gradually to field conditions with efficiency of 60%.

This paper gives an outline of micropropagation of Pontederia lanceolata. Pontederia l. is a widely used aquatic plant, therefore there is an increasing demand for them, which can be satisfied only by in vitro culture. Research was carried out to find the best nutrient media conditions for micropropagation and acclimatisation of Pontederia lanceolata.

During 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.

Eighteen pea breeding lines and three check cultivars were tested in two years with and without irrigation. The linear regression can explain only a small part of GEI so the use of regression technique was not possible for interpreting the data. In this case the ecovalence, stability variance and superiority measure stability parameters cannot describe properly the genotype's response. With the AMMI method it is possible to group properly the genotypes according to their response.

Widespread application for herbal medicines based on Hyperici herba has been experienced in the last few years, especially in the treatment of depression syndrome. As the wild origins could not satisfy the market demands neither in quantitative nor in qualitative res­pect, the necessity of the development of intensive growing methods has been raised. In the course of our investigations we intended to clear up the morphological and chemical variability among and within populations of different origin in order to start a new breeding program. According to our data, growth dynamics of populations could be characterised by a logistic curve. According to the time of flowering the populations formed early, middle and late groups. Morphological diversity among populations was measurable in differences of flower length, plant height, different leaf types and plant habit, according to which characteristics groups were distinguished. Generally, the accessions were the most homogenous in plant height (CV: 7-15%), followed by inflorescence-lengths (CV: 11-36%) and the least uniform characteristics proved to be the number of flowering shoots (CV: 14-59%). The greatest morphological heterogeneity was experienced in the accessions of wild origin as it has been expected. In the second vegetation period generally a much better homogeneity was obtained, than in the first year. The most outstanding accessions produced 1.2 t of dry flowers and 4 t of dry flowering shoots, calculating to one hectare area. The individual yields varied on a large scale in each population (CV: 18-70%).

The content of hypericin varied between 1,85 and 9,9 mg/g in 1996, and between 0,18 and 2,70 mg/g in 1997, showing high individual divergences. Flavonoid values -including first of all hyperosid, rutin and quercitrin - reached 17-39 mg/g in the first and 15-20 mg/g in the second year, respectively. Individual and seasonal variation was less than in hypericin. A joint high level of these two compound groups seems to have low frequencies.

The superior population were selected for further breeding.

Present paper describes an investigation concerning seasonal water use and foliage area development of apple trees. Sap flow velocity was measured in the trunks of five years old apple trees cv. `Florina'/M.26 by a thermal dissipation (Granier) method from 20th of May to the end of September in 1998. The development of foliage area was estimated by a method including leaf area measurements, recording of leaves and shoot length. The foliage area reached to 70% of the maximum yearly value at beginning of June. The remaining 30% developed to the end of August. The leaf area specific water use was considerable higher in June and July, than in second part of summer. The trends of ET-FAO and water use curves differed mostly in the late season: the ET-FAO curve falls quite in September compared to August, whereas the value of water use was a similar as in August. This insensitivity of ET-FAO in this period may be a great disadvantage while using the Penman-Monteith equation in irrigation scheduling of apple.

The effect of water supply on availability of macro nutrient elements (N, P, K) by the plants in the soil and their transport in the plants were examined. In a field experiment two grapevine varieties characterized by higher (White Riesling B 7) and lower (Kövidinka K 8) water requirement were compared on the basis of N, P, K concentrations of leaf blades, petioles and berries. A different water supply of the vineyard was achived by striped coverage of the soil with plastic foil to exclude rainfalls from the beginning of May to ripening. Humidity of the soil decreased as the vegetative phase advanced. Soil cover resulted in 25-30% decrease of the water content in the soil at flowering but this difference gradually disappeared till veraison (i.e. the start of intense growth of the berries). The water consumption in the White Riesling B 7 plantation was more intensive. Mobility and availability of N, P, K in the soil was restricted by water exclusion (i.e. plastic soil cover) at flowering. Nitrogen was slightly affected, whereas P and K were in a higher extent. Comparing the transport of nutrient elements in the two varieties, leaf blades of Kövidinka K 8 contained less N and more P and K than White Riesling B 7 at flowering and more N and P and less K at ripening. Water deficiency inhibited K accumulation in the berries of White Riesling B 7, while this effect did not appear in Kövidinka K 8.Water exclusion decreased the yield of White Riesling B 7 already at lower bud loading, the yield of Kövidinka K 8 was affected only at higher bud loading. The higher yields of the treatments in Kövidinka K 8 plantation support the superior performance of this variety under the hot and dry climate of the Hungarian Great Plain.

Samples of 50 wrinkled-seeded pea (Piston sativum cv. ‘Farida') were soaked for 0.5, 1, 4, 8, 24, 48 and 72 hours at temperature of 5, 10, 15 and 20 °C in distilled water before germination. Water absorption, percent of germination, vigorous seedlings and dry weight of normal seedlings were assessed after 8 days. Respiration of short and long seedlings were checked by IRGA, LI-COR 6200 photosyn­thesis system. Most plants had more or less respiration but some of them already had photosynthesis. Differences in the amount of water absorbed were evident after one hour, only. Water amount was increased by increasing soaking temperatures and times. The maximum was achieved after 24 hours. Normal germination percent was not improved at any soaking time and temperature combinations but it was significantly declined at 10 °C with soaking time combinations and at 20 °C for 72 hours. The seedling vigour values were not very different at the higher soaking temperatures, but the treatments at 20 °C temperature with 8 and 24 hour soaking periods are proved to be optimal for seedling vigour. At the low soaking temperature the increase of the soaking period influenced the seedling vigour. Reduction of dry weight percent was noticeable by any soaking time related to temperature and compared with the control.

The effect of sulphur and lead on growth of muskmelon (Cucmis melo L.) sweet ananas was measured under plastic tunnel. Lead (Pb) was applied at the rate of 0, 75, 300, 600 and 1200 pg/g of soil in factorial combination with treatments of 0, 48, 80, 112 and 224 mg S/kg soils. Muskmelon growth was reduced by increasing Pb concentration and/or by removing S from the growth medium. Lead concentration in plant tissues increased linearly with increasing Pb concentration in the growth medium. Increasing S concentration in solution reduced the effects of the 75-1200 pg Pb /g soil treatments. Increasing S concentration in soil increased shoot and root growth at high levels of Pb. Increased levels of S in the growth medium decreased Pb concentration in shoot and root tissues and increased growth of muskmelon. The reduction in Pb toxicity at high S supply may be due to reduced root absorption of Pb.

Common bacterial blight (CBB), caused by Xanthomonas campestris pv. phaseoli (Xcp). is a major disease problem of common bean (Phaseolus vulgaris L.). The inheritance of resistance in Xrl and Xr2 lines to two isolates of Xcp was studied in the F2 and F3 popu­lations from the crosses between these lines and the Masay variety (susceptible to Xcp). Segregation patterns indicated that different single recessive genes presumably in coupling phase linkage determined the resistance to the HUN and EK-1 1 strains of Xcp in both lines. The presence of some minor, modifying genes beside the monogenic genetic background of resistance was also observed. Xrl and Xr2 lines represent valuable new monogenic genetic sources in resistance breeding to CBB.

The Pseudomonas savastanoi pv. phaseolicola (PS) is one of the most significant stressors of bean (Phaseolus vulgaris L.). Chemical and agrotechnical treatments have minor importance, so breeding has great part in the protection against this pathogen. Most of the cultivars are susceptible to PS. The genetic background of resistance in the plant is a complex system. Leaf resistance is a monogenic system, but there are some modifier genes. The pathogen species can be divided into different races.

To understand the functioning of this resistance gene, experiments were carried out using bean varieties with different genotypes and near isogenic lines of bean. Eight lines were tested. Our main objective was to test bean lines with PS with high virulence.

The experiment was made in greenhouse and on field. The virulent bacterium strain has been isolated in Hungary.

The changes of carbohydrates were tested after infection. In homeostasis the level of carbohydrates (especially glucose and fructose) were higher in susceptible lines. In case of artificial and natural infection the decrease of glucose were more significant in susceptible lines than in resistant lines. In the leaf samples from systemic chlorosis the level of this carbohydrate increased.

These changes are connected with the level of resistance, but more experiments are needed to verify this assumption.

Fruit 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.

The duration of effective bee pollination period was limited by caging flowering branches for shorter or longer time in blooming fruit trees in a number of experiments during the past decades. In the case of self-sterile fruit species and cultivars (apples, pears, quinces, some plums, some sour cherries) even partial limitation of the effective duration of bee pollination period significantly reduced the fruit set and the yield. In the case of self-fertile apricots the effect of the total and also the influence of partial limitation of bee pollination period was the same as in the case of the mentioned self-sterile fruits. On the other hand, in the case of another self-fertile fruits (some plums, some sour cherries), the effect of partial limitation of bee pollination period was usually small, but complete (or incomplete but strong) limitation of be pollination usually resulted in a strong reduction of yield. This means that not only self-sterile but also self-fertile fruits clearly depend on insect (bee) pollination. This is because pollen dehiscence of anthers and the receptive period of stigmas do not overlap in time within the individual flowers. Stigmas in self-fertile trees, therefore, need pollen carried by bees from another flowers of the same tree (or compatible pollen from another trees). Accordingly, additional bee pollination (moving bee colonies to the orchards in flower) is needed to all kinds of temperate-zone fruit tree species when bee visitation of plantations is not abundant enough for some reasons.

Under conditions of Hungary, more than 400 varieties of apple, pear and quince varieties have been observed for time of blooming and fertility relations in order to check the possibility of their use for intense plantations in different combinations with polliniser varieties. Low (below 3%) rate of self-fertility occurred at 65% of apple varieties. That partial self-fertility, however, is far from being sufficient to produce acceptable yield, thus allogamous pollination is absolutely necessary. The same is true for the rear and quince varieties grown in Hun­gary, too. The normal development requires the presence of viable seeds in the fruit set, most in quince, therefore, association of the right varie­ties is most important in that species. Apple and pear varieties are assigned according to their blooming time to 4, quince varieties to 3 groups. The yield of all three pomaceous species declines with the growing distance from the potential pollen source. In the intense plantations, the critical (maximum) distance to be observed is 20 m for apple and 15 m for pear and quince. In combining the placement of varieties, also the principles of a variety-specific cultivation are to be considered carefully. The double objectives are satisfied most by the system of Malus­pollinisers developed for intense plantations.

The 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.

Authors studied the autofertility depending on natural self pollination (autogamy) in 59 pear cultivars during 4 seasons at three locations with different ecological conditions (Helvetia, Kecskemet-Kisfai, Keszthely). The aim of the experiments was to determine the autogamous tendencies of varieties hitherto unexplored in the Hungarien gene bank, or to check data found in the literature. A total of 42616 isolated pear flowers produced 1.2% fruits with at least one viable seed in each. The 59 varieties observed did not set fruit by autogamy on either of the three sites during the four years of the study. The triploid (3n=51) varieties were entirely self-sterile. According to the highest autogamous fruit set, during the experimental period, the varieties have been assigned to four groups: (1) Entirely auto-incompatible (0% fruit set), (2) auto-incompatible (0.1 to 0.9%), slightly self fertile (1.1 to 5%) and (4) self fertile (5.1 to 10%). According to the number of viable seeds per fruit resulting from autogamy, the varieties are assigned to three groups as (1) low seed content (less than 3 seeds per fruit), medium (3.1 to 5) and (3) high (more than 5 seeds). Thus, the assessment of the number of seeds per fruit resulting from autogamy is indispensable as a proof of the absence of parthenocarpy.

Regular observations and experiments were performed during a 14 year period on 6 sour cherry varieties. The morphological traits of leaves and fruits were compared, and the phenology of blooming as well as of ripening dates served to start an estimation of the possibilities of mutual pollination and the planning of harvest operations. Experiments involved obligate autogamy, artificially controlled allogamy and open pollination in order to reveal self-fertility, self-sterility or inter-incompatibility relations.

The varietal characters represent, each, different values in the distinction of the items, because of their intra-varietal variability. From that point of view, the most reliable are the data of blooming and ripening time, fruit size and the fertility relations.

Inter-incompatibility was observed between the group of self-fertile, "Pándy type" varieties (`Újfehértói fürtös’, ‘Debreceni bőtermő’, ‘Kántorjánosi’) on one side and the selection of Pándy 7', a self-sterile variety on the other side. Unilateral incompatibility has been detected within the former group of new, self-fertile varieties, the combinations: (`Újfehértói fürtös’ x ‘Debreceni bőtermő’ as well as `Újfehértói fürtös’ x Kántorjánosi’.

Our results prove the close kinship between those three new varieties and the original Pándy variety on the base of being highly similar in their morphology and also of the fact of their inter-incompatibility, though unilateral.

A 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.

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

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

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

During the last three decades, diverse effects of nitrogen application on the performance of apple trees were studied in field and pot experiments at the Experimental Station of University of Horticulture and Food Industry. The basic experiment, using different rates of nitrogen in kg/ha (check, N-50; N-100; N-200; N-400; and N-800), was carried out for a period of 13 years, thus including almost the whole bearing period of Jonathan apple trees on M.9 rootstocks.

The need of nitrogen in apple orchards on M.9 rootstock and soils with moderate humus content can be decreased considerably. Nitrogen application significantly increased leaf nitrogen and magnesium, but depressed leaf phosphorus and potassium content. With increasing doses of nitrogen fruit nitrogen content significantly increased and parallelly phosphorus and potassium content decreased. Even the lowest rate of nitrogen application decreased the red colouration of fruits. A direct negative correlation between nitrogen fertilzation and fruit firmness was not proved. No close and significant correlation between fruit quality parameters and the nitrogen content in leaves, sampled at different dates, was revealed.

Producing high quality apples in mature trees of the cv. 'Golden Delicious' is rather difficult because of the russeting of it's fruits, especially in seasons of high relative humidity and/or wetness.

Earlier experiments proved the possibility to decrease russeting by treatments of GA₄.₇ during a period after petal fall.

Phyl-Gold, a product of Phylaxia Co. (ai. 10 g1^-1 GA₄.₇) was applied to inhibit russet formation in fruit skin of 'Golden Delicious' apples. Four consecutive sprays were carried out (with 10 ppm a.i.) in weekly intervals, starting at petal fall and tank-mixed with the current pesticides of the plant protection program.

Due to the GA₄.₇ application the russet formation decreased at a rate of economical importance. As for the side-effects of treatments, fruit set was reduced slightly in trees treated, however, there was no consequent influence on return bloom.

Direct sowing in 16 cm deep trench covered with perforated plastic sheet (for 3 weeks), transplant using, and uncovered direct sowing (control) was tried on 2 locations, with 2 varieties (very early Kecskeméti korai extra, and middle early Kecskeméti SC-370) in Szarvas on loamy soil, and in Kecskemét on sandy soil in 1996 — after a preliminary trial concerning perforated plastic covered trench sowing in Szarvas, in 1995.

The plant height (weekly), the average leaf number/plant, the total leaf area (once), the total yield, the quality of cobs, and the earliness was measured. The results are:

1. Kecskeméti korai extra during the first 6 week period the transplanted plants were the highest, but from the 7th week the plants which were sown in trench and than were covered with perforated plastic sheet (for 3 weeks) were the highest.
2. SC-370: The transplanted plants were the highest-until the end of plant height development.

The plant height development stopped at the 9th week of the measurement by early, - and stopped at the 10th week by middle early variety. The average leaf number/plant varied between 9,25-10,50 and was not influenced either by variety or by the treatment. The total leaf area was (on 5th of June) the largest by transplanted plants, which was followed by plants that were sown in trench and then were covered with perforated plastic film (for 3 weeks).

2. The highest yield was observed by plants, which Were sown in trench, and then were covered with perforated plastic film (for 3 weeks). Transplanted plants followed it.
3. Quite the total yield (98,3%) of transplanted Kecskeméti korai extra variety plants were harvested on 4th July. 89% of the total yield was picked up of trench sown and then with perforated plastic covered plants. The harvest of uncovered control started on 15th July. The harvest of transplanted SC-370 plants started 19th July, when more than half of the total yield (57%) was picked. The uncovered control was harvested 29th July.
4. The weight and the measure of cobs generally were not influenced by the treatments, but the average weight of the cobs of the transplanted Kecskeméti korai extra plants (0,21-0,18 kg) are less than the, requirement.

GIS utilization in the site selection of a new fruit plantation

The main fields of open ground ornamental plant cultivation in Hungary are: Woody ornamental nursery products (trees, shrubs, conifers) (950 ha cultivation area and 4-6 million plants sold per years^.; Rose bushes (around 140 ha and 2-4 million bushes per year); Perennial plants (20-30 ha and 3-4 million plants per year); Dried flowers (200-250 ha of land and a production value of 5-700.000 HUF per year). The paper is discussing in detail the structure, development and tendencies of ornamental nursery production (with figures in tabulated form) and later gives shorter assessments of the present state and perspectives of the other three fields. Finally, a list is given of the Hungarian professional associations and unions, education and research centres involved in ornamental plant growing and trade.

On the basis of a six-year experiment a method was elaborated for forcing and off-seasons growing of tulips, narcissus and gladioli under frameless plastic cover. The advantages of this cheap energy-saving method are manifested in an improved quality of flowers and essentially in the earlier flowering. With this method mostly first-class flowers can be obtained immediately after the season of forcing in heated constructions with plastic cover, and anticipated outdoor flowering.

The possibilities of applying the method are studied on further ornamental plant species (other bulbous plants, Paeonia lactiflora, annual ornamentals).

Seed certification and EU conform legislative harmonization in Hungary