Susceptibility of progenies of some Ma/us species to apple scab was evaluated. Susceptibility of hybrid families was observed first in greenhouse after artificial inoculations by the suspension of the pathogen, Venturia inaequalis (Cooke) Wint., then in open field. The Hungarian type of Malus floribunda, which proved to be scab resistant in our examinations, has a positive effect on the segregation of progenies to resistant and susceptible individuals as a male parent, not depending on the rate of susceptibility of the other parent. However, the German type of Malus floribunda and Malus prunifolia act as dominant, highly susceptible parents.

Malus x purpurea and Malus baccata, which proved to be highly susceptible to apple scab in open field and in artificial inoculations, transmits its susceptibility only slightly to its progenies as a male parent.

According to our experiments, the inheritance of scab resistance of Malus floribunda cannot be considered as monogenic, as published by other authors.

Scab susceptibility of parents influences the segregation of progenies to resistant or susceptible individuals. The moderately scab susceptible `Idared' as female parent has a statistically proved positive effect on the segregation of its progenies.

More factors indicate the appearance of a new race of Venturia inaequalis (Cke.) Wint.: change of the symptoms in the greenhouse; considerable increase of susceptible individuals after greenhouse inoculation in 1997; more and more progenies of the male parent Malus floribunda became susceptible to scab in open field.

Research 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.

Vegetative propagation by hardwood cuttings is a very simple and cheap method for production of plum rootstocks. The aim of this study was to examine if this propagation technique is suitable for practice of three plum rootstocks and find the time or period when the percent of rooted cuttings is maximal. Based on our results, hardwood cuttings of the rootstocks tested have the rooting potential acceptable for practice, however, for Fehér besztercei in the previous literature leafy cuttings are recommended. Fehér besztercei reached 74.0% rooting, cuttings of Sainte Julien GF 655/2 rooted in as high percentage as 78.3%, and Marianna GF 8-1 had 88.3% rooted cuttings. Rooting potential of hardwood cuttings depends on more factors, one of them can be their dissimilar sensitivity for the diverse environmental circumstances at the different propagating dates, affecting through the internal biochemical changes that can be in relation with the differences in their dormancy.

The cuttings of Marianna GF 8-1 take root easily, but in some years the conditions were less favourable for reaching maximal rooting. For taking cuttings the period from the beginning of October until December was optimal. For Fehér besztercei the optimal date of cutting collection was around the end of October, but in some years the rooting in the middle of December was also high. Sainte Julien GF 655/2 definitely rooted best in October. The treatments with different IBA concentrations in two years affected differently the rooting percentage. The rooting of Marianna GF 8-1 and Sainte Julien GF 655/2 is barely influenced by the different hormone dose in both years. Hardwood cuttings of Fehér besztercei rooted definitely better when treated with 2000 ppm IBA in comparison to untreated ones, while in 2001-2002 there was no difference between 2000 and 4000 ppm.

Field experiment was conducted to study the replant problems of grapevine and apple. Plantings were in three different fields: on virgin soil, on apple replant soil and on vine replant soil. Each field was planted with 60 pieces of grafted vine (variety Bianca on rootstock Berl. X Rip. T.K. 5BB) and 60 pieces of grafted apple (variety Gloster on rootstock MM. 106). Fungicide (BUVICID K with 50% captan agent, 0.5 g/1 1 soil) and nematocide (VYDATE 10 G with 10% oxamil agent, 0.03 g/1 1 soil) treatments were used in the soil in order to identify the causal factor of the problem.

Biological soil test was conducted to test 17 soil samples of 11 wine districts and vine growing fields in plastic pots, under shading net. No root pieces were left in the soil. Two bud-cuttings of the Berl. X Rip. T 5C rootstock varieties were used as test plants. In each case, samples were taken from the vineyard and from the virgin soil. One fourth of the soil from the vineyard was left untreated and the other three part was treated with nematocide, fungicide or heat.

The results of the field experiment suggest that there was no problem growing grapevine after apple and apple after grapevine, but both species had been inhibited growing after itself. The fungicide and nematocide treatments did not succeed in determining the casual factor of the problem. Heat treatment of replant soil (in pot test) was useful in AS and VNS soils.

Results of biological soil test suggest, that grapevine replant problem do not occur in every vineyard. In fifty percent of soils, no significant differences between the treatments for shoot length, weight of cane, length, diameter and wood:ratio of the fourth internode were observed. In one case, difference was not found in any of the measured characters. However, fruiting bodies of Roesleria pallida (Pers.) Sacc. and the mycelium of Rosellinia necatrix Prill. were observed in this sample. In other samples, there was no significant difference between the treatments, but nematode and fungus infection appeared to be involved in increased shoot growth in nematocide and fungicide treated plants (mycelium of Rosellinia necatrix was detected). In other samples, the fungus infection caused significant difference between the virgin, untreated and fungicide treated soils and infection of Rosellinia necatrix was observed.

Earlier results of experiments with paprika grown in soil have shown the high sensitivity of the crop to nutrient supply. According to these findings, yield and also fruit quality are highly affected not only by the nitrogen and potassium level, the concentration of nutrient solution, but also by the nitrogen-potassium ratio. Our preliminary tests have also proved, that the composition of the nutrient solution, first of all, the N/K ratio has a definite effect on the yield quantity and quality. Therefore we have investigated the ratio of the two nutrients with the aim of developing a nutrient solution of optimal composition for white fruited paprika forcing. The most balanced burden of the plants was found when the N/K ratio was 1:1. The highest yield was produced with N/K 1:1.3. Significant yield reduction (30%) was found with the treatment N/K 1:1.9 as compared to the 1:1.3 and 1:1.6.

In our experiments, we have chiefly tested the salt sensitivity of sweet pepper varieties. In cold forcing, 0.3 1/plant nutrient solutions of different NaCI content were given twice weekly. EC of the nutrient solutions containing 0.25% Volldünger Linz complex fertilizer was made up to 6, 10, 14 and 18 mS/cm, respectively, by 2.51/9.17/17.97/26.76 g/m² doses of pharmacopeal NaCI every week. The solution used for the control treatment contained Volldünger only (EC 4.4 mS/cm). Irrigation was made with pure water (EC 0.6 mS/cm) when necessary.

The varieties chosen for the experiments were the following: Feherözön, HRF F₁, Syn. Cecei (of white, conical fruit), Boni (of white, blunt, infolded fruit), Titan F₁ (of pointed, hot fruit) and Pritavit F₁ (of tomato shaped fruit).

In general, the symptoms caused by NaCI treatments (with doses higher than 10 g/m² weekly) have been the following:

• They have reduced the leaf area, the height of the plants, the total and the early yield, the number of fruit set per square meter, the average weight of the fruit (and, in some measure, fruit length, too) and the thousand seed weight.
• They have increased the calcium and the chlorine content of the leaves and fruits and the dry matter content of the fruits.
• They haven't affected the dry matter content of the leaves, the nitrogen, phosphorus and potassium content of the leaves and fruits, and the germinating ability of the seed.
• The effect on stem diameter and on seed production per fruit has been contradictory in some cases.

The effects of the intermediate treatments haven't been explicit in several cases.

The results of the examination of cuticular secretion have indicated the increase of the sodium and chlorine content of the leaves. This can be important in field growing where the rainwater may wash out a part of sodium and chlorine from paprika leaves.

The hot, pointed variety and the tomato shaped paprika haven't shown clearly higher salt tolerance than the varieties of white fruit colour.

By our experiments, we wished to answer the question: may top-dressing with nitrogen and phosphorus fertilizers, respectively, improve the quality of transplants grown in trays on a substrate enriched by 2 kg/m³ of retarded fertilizers?

The experiments started in spring and autumn 2002, in a large volume plastic house. The seedlings were grown in trays. Seed was sown directly into KITE trays of 187 cells (28 cm³ volume per cell, 779 seedlings per square meter). The trays were filled by "loose filling" (without packing) with the following soil mixture: 50% Baltic highmoor peat, 50% 'Nitrite lowmoor peat, 1,5 kg/m³ feed chalk, 2 kg/m³ slow acting chemical fertilizer of phosphorus overweight, 2 kg/m³ superphosphate. The test plant was the vegetable paprika variety `Tizenegyes'.

The trials were made in order to clear up if top-dressing done once or twice improves the quality of the seedlings. For this purpose, perfectly soluble fertilizers of phosphorus or nitrogen surplus were used. 3 I fertilizer solution of 0.2% concentration was given per square meter on every single occasion. The control plots received no top-dressing.

The following parameters were registered: stem diameter, plant height, fresh weight of the top, dry matter content of the top, fresh weight of the root system per plant, dry matter content of the roots.

The experimental results with top-dressing have clearly proved the insufficiency of mixing 2 kg/m³ of retarded fertilizer into the substrate, as usual in raising paprika seedlings in trays, because of the long period of transplant raising. According to our experiments the additional nitrogen fertilization influences positively the development of green parts of plants, while the multiple application of fertilizers with higher phosphorus-content helps to develop a strong root system. We suppose, that the more often applied additional fertilizers, maybe the combination of fertilizers with nitrogen and phosphorus amount could give use even better results.

Foliar boron fertilisation has had positive influence only on carotene content. Results were evaluated with chemical analyses and sensory tests. It has been observed that sensory tests are able to detect bitter flavour and also to measure its interaction with sweet flavour. Sensory tests for evaluation are generally used in the EU, also in the case of fruits and vegetables. With the aid of students and staff having received training and acquired practice, our University has the possibility to complete chemical analyses in such a way that satisfies modern demands, as well as facilitating the sale of the products on foreign markets.

14 combinations of mechanical and also physical (thermal) weed management techniques are compared for organic growing of carrot. Crop of our weed management research is carrot because of its difficulties in weed management (long growing period, poor weed tolerance) and because carrot needs to be important product of organic farming. Herbicide treatment is used as control — cultivator, brush hoe, hand hoeing and hand weeding are mechanical control tools and flame weeder is used for thermal control. Measured parameters are the weed cover, cover of the crop and dry mass of them. Result of the two appraisable years shows contradictory results, which contradiction can be justifiable with different weather conditions of these two vegetation periods. In 2000 brush hoe was significantly the best in interrows but in the year 2001 cultivator combined with hand weeding in rows seemed to show the best result. We can see in this example that agriculture and weed management depends very much on the weather of the year, so that is why it is so difficult to develop a method, which can be generally used for organic weed control of carrot.

The European market demands vegetable products of the highest quality and this commercial quality must be maintained till the goods reach the customer. One of these important quality parameters is the fruit firmness of pepper.

The experiments were aimed at to find out the influence of different growing methods (soil or rockwool-based) and pruning technologies (to 1, 2, 3 or 4 shoots) on the yield and fruit firmness of three pepper varieties (HO F1, Karpia Fl and Pritavit F1) which are common in Hungary. Fruit firmness was measured by the non-destructive impact method.

On the basis of the results, in unheated forcing the pruning to 1, 2 or 3 shoots can be suggested for all three varieties, as well as the utilisation of rockwool in their growing.

The non-destructive impact method has been found suitable for testing the fruit firmness of pepper varieties. In the experiments involving different growing mediums pepper stands were found to show significant differences, however the different pruning methods had no significant influence on fruit firmness.

The importance of ecological farming in Hungary is increasing. The utilisation of organic seed is regulated by national law. In our experiment the effect of two plant conditioning substantial: Biokál and Biomit Plussz were tested on the germination of seed. Our test plant species was garden pea (Pisum sativum L.), the most important vegetable in Hungary. The experiment was carried out in the germination laboratories of the National Institute for Agricultural Quality Control after international rules. The germination, the length of root and shoot were measured. 4 hours soaking of pea seeds in 30% solution of Biokál gave the best result. Our results could help to make the field emergence of organic seed faster and safer.

It gets more and more popular to grow transplants in different trays for the field vegetable growing. The best transplant-growing substrates in the world are made of peat. The peat is applied to provide an optimal supply of plants with water and air. To improve the water regulation and the structure of the mixtures there are often mineral matters used in different amounts. By measuring the physical properties of soil mixtures based on peat, the flexibility can be measured by Stable Micro System type table penetrometer. Our measuring confirmed the increase of bulk and flexibility of different kinds of peat by watering.

The transplant-growing with root balls gets more and more popular and time to time the only method even in high-quality lettuce transplant-growing. To work out the technology of transplant-growing in trays it was needed to define the accurate physical and chemical consistency of applied soils.

The transplant production in trays could become a good method in field-grown lettuce technologies. The production of transplants of good quality with this technology could be realised only by accurate soil mixtures.

The matter of transplant-growing substrates could be a low-moor turf. Its qualities could be positively influenced by adding minerals like bentonite in amount of 5 (or 10) V%.

To ensure enough phosphorus for the demands of transplants we have to add more fertilisers. The best results by lettuce we got by adding 4 kg/m³ superphosphate to the soil mixture.

In this study we carried out experiments with soil samples originated from the Haschberg variety elderberry orchard and wild-growing plants from Szigetcsép Experimental Farm.

During the examinations we wanted to know how the black polyethene foliar soil coverage influences the quality of soil and the distribution of different nitrogen forms.

We studied the individual covered (foliar soil coverage for every plant), the full covered (foliar soil coverage was laid in the rows) and the uncovered threatments.

During the experiments we pointed out that the foliar coverage influences the condition of the soil unfavourably. Because of the coverage there is less air flow in soils, the lack of oxygen leads to degradating of soil life and results humus materials of poor quality.

Our experiments aimed at comparing the yields of the oyster mushroom hybrid Pleurotus HK 35 with those of the species Pleurotus sajor-caju on wheat straw. No data concerning the yields of the "Indian oyster" has so far been published in Hungary. The objective was, on the one hand, to discover what "phoenix" yields could be expected on 100 kg substrate, and on the other hand, to compare the yields with those of Pleurotus HK 35 which plays a dominant role in commercial production. We were also curious to know the amounts of harvest losses with the two mushrooms when picked with cut stems. It would be advisable to make progresses in developing production technology, especially in increasing yields. Considering that in its native place this species is able to provide yields even at temperatures of 22-28 °C, it seems possible that in hot summer months, as a shift from the hybrid HK 35, the production of the "Indian oyster" could be more economical.