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A model of full bloom starting date of some white Vitis vinifera L. varieties grown in Helvecia
21-25.Views:293Grapevine bloom happens between end of May and the middle of June in Hungary. However, climate change in the past decades and the occurring weather anomalies can modi fy this date to a diverse degree. Among the weather factors, the bloom starting dates of grapevine depend mostly on temperature and relative humidity of air. There can be significant differences between North American and East Asian grapevine varieties, and of course, the early and late ripening varieties. ln this approach we investigated the starting dates of bloom between 2000 and 2004 for grapevine varieties grown in Helvecia, as well as the effectiveness of a temperature sum model. The model is based on the widely accepted cumulated heat sum concept, and the optimization was made for the least standard deviation in days as well as on the least average absolute deviation in days and on the least maximum deviation in days. The model is connected directly to a similar model for the budburst date of the same plantings (Hlaszny & ladanyi, 2009). We set the optimum lower base temperature to I 0.45 °C and the upper base temperature to 26 °C. The absolute values of the differences between the observations and the model estimations move between one and six days with an average of 1.81 days
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The effect of rootstock on the tree size of apricot cultivars
57-58.Views:245The apricot is propagated on several kinds of rootstocks in Hungary. The main aspects of selecting rootstocks are as follows: adaptability to environmental circumstances, primarily soil conditions, ensuring the tree size that complies with the cultivation method, and compatibility with the grafted cultivar. At advanced, intensive orchards rootstocks ensuring smaller tree size are privileged. For the establishment of the appropriate cultivation system, it is important to be aware of the expected growing vigour and tree size of certain cultivarrootstock combinations when the orchard is designed. In the course of our experiment the size of 15-year-old trees of 4 apricot cultivars were examined on several rootstocks at an orchard in Siófok. On the basis of the data measured for each cultivar-rootstock combination, it can be stated that trees on wild apricot (P. armeniaca) rootstocks are the largest in size. Trees on prune (P. domestica) rootstock have 10-15% smaller crown volume than the previous combination. Trees on bullace (P. insititia) rootstock have the smallest tree size and their crown volume is 30-50% smaller than that of the trees on P. armeniaca rootstock. Thus, the application of prune and bullace rootstocks is beneficial at intensive apricot orchards as the size of trees can be reduced by their usage. However, their compatibility with the cultivars and their adaptability to the ecological conditions of the production site have to be tested before applying them widely. In the course of our research incompatibility was not experienced for any of the cultivar-rootstock combinations examined. Nevertheless, the drought tolerance of the rootstocks examined showed significant differences. Trees on P. domestica or P. insititia rootstock requires more water than those on P. armeniaca rootstock, therefore, they have to be irrigated.
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Effect of a nanotechnology-based foliar fertilizer on the yield and fruit quality in an apple orchard
29-32.Views:1229Nutrient management is a determining element of the technology in fruit production. Significance of foliar fertilization has been increased continuously over the last years, as it can improve directly the vegetative and generative performance of the trees. In this study we aimed to evaluate the effect of a nanotechnology-based foliar fertilizer (Bistep) with 1, 3, and 5 l/ha dosages on the yield and fruit quality parameters in an apple orchard during 2016 and 2018. According to our results, crop load increased with 29% in the third year of the experiment with the application of 5 l/ha Bistep treatment compared to the control treatments. Fruit weight was also improved in each year, as values of fruit weight in all treatments were higher than the control one (3.0-13.0% growth). Fruit surface color increased with 2-18% due to the foliar fertilizer. During the three years, leaf length was 9.5-9.9 mm on the control trees, as 9.8-10.4 mm was measured on the fertilized ones. In conclusion, yield and fruit quality can be improved in apple orchard using a nanotechnology-based foliar fertilizer.
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Tending operation models for white poplar (Populus alba L.) stands growing under sandy soil conditions
125-127.Views:327Integrated research aimed to intensify the practices of afforestation especially of white poplar and grey poplar woods. A new, simplified tending procedure has been developed to substitute earlier models considering the target diameter by right spacing as a tool to achieve adequat quality of logs. The practice-oriented model may help the qualitative improvement of white poplar growing technology in Hungary as well as in Serbia.
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Flower characters and self-fertilization capacity in relation to the bee pollination at sour cherry cultivars
121-132.Views:839Detailed studies and comparisons were carried out on those flower characters of sour cherry cultivars that may affect bee pollination of flowers. Flower characters of sour cherry are fairly similar to other temperate zone fruit tree species. Their relatively small flowers distinguish the Cigánymeggy-types of cultivars from the flowers of tart cherries cultivars that are conspicuously larger, almost as large as the sweet cherry flowers. The relative position of flower organs was much more variable according to the season than according to the cultivars. So the differences were rather the consequences of seasonal effects than of variety features of sour cherry cultivars. As far as individual cultivars are concerned differences in the nectar production and the sugar concentration are revealed rather between groups of cultivars than between individual cultivars. The pollen production of flowers was extremely changeable in consecutive years. Most honeybees collected nectar at sour cherry flowers; pure pollen gatherers and mixed behaviour bees were half as frequent but differences among the behaviour of honeybees according to cultivars cannot be stated. The fidelity of honeybees to sour cherry is less expressed than to some other fruit tree species. Accordingly, it is very strongly suggested to take the competitive effect other plant species (weeds) flowering in and around the orchard carefully into account when organizing additional bee pollination in sour cherry plantations. Several sour cherry cultivars possess more or less self-fertilization capacity but this is greatly changeable according to the season. It has been proved that self-sterile sour cherry cultivars are sensitive even on the partial restriction of the effective time of bee pollination and it is to be stressed too that even in the case of partly self-fruitful cultivars bee pollination is also vital in yield formation because medium or strong restriction of the effective bee pollination period is of a definite negative effect on their fruit set and yield. In years with unfavourable weather the yield can dramatically be reduced sometimes down to nil. However, very high fruit set is also unfavourable because a negative correlation was detected between the final set and the mean mass of fruits.
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Comparative investigation on Hypericum perforatum L. populations of different origin
56-60.Views:449Widespread 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.
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In vitro sensitivity of Monilinia laxa to fungicides approved in integrated and organic production systems
59-61.Views:524The aim of this study was to test the in vitro sensitivity of two isolates of Monilinia laxa to fungicides approved in integrated and organic production systems. In vitro efficacy of 7 fungicides (Champion 50 WP, Kocide 2000, Nordox 75 WG, Olajos rézkén, Kumulus S, Rézkén, Rézoxiklorid) and another 6 fungicides (Score 25 EC, Efuzin 500 SC, Systane, Folicur Solo, Zato Plusz, Rovral) approved in organic and integrated production systems, respectively, were tested against brown rot of sour cherry. The three isolates showed differences in sensitivity to fungicides. Fungicides (with active ingredients of copper and sulphur) applied in organic production showed relatively high percent growth capacity of M. laxa. Rézkén and Kocide 2000 showed the highest and Kumilus S the lowest efficacy against brown rot. Fungicides applied in integrated production showed relatively low percent growth capacity of M. laxa. Score 25 EC showed the lowest and Rovral and Folicur solso the highest efficacy against M. laxa.
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The future of the apple growing branch in Hungary
91-98.Views:544The present study deals with the actual situation of the Hungarian apple production in order to outline the chances of the future and the trends of the development to be anticipated. The general conclusion is accepted that on the long run Hungarian apple production ought to be reorganised. The conditions of keeping the position on the international market are outlined. The main concern is the aging of the plantations, i.e. 40%of them being more than 25–30 year old, and produce apple being suitable for processing only. Organisation of growers is rudimentary, export markets are limited, and buyer’s market is everywhere dominant and is getting more severe. All those circumstances anticipate the reduction of the apple growing branch from the present 35 000 hectares to 15–20 000 hectares within a period of less than 10 years.
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Review of the molecular background of self-incompatibility in rosaceous fruit trees
7-18.Views:432This review gives a presentation of the gametophytic self-incompatibility system in the roscaeous fruit trees. Studies to discover the pistil (S-ribonucleases) and pollen-part components (F-box molecules) are summarized and models for the self-incompatibility reactions as well as their molecular background are discussed. We describe how mutations within the S-RNase or F-box genes can contribute to the transition from self-incompatibility to the self-compatible phenotype in many fruit tree crops. The current state of the arts is compared to the information obtained in other plant species possessing similar incompatibility system.
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Translocation of diquat dibromide
105-107.Views:258The aims of our work were to answer the following questions: 1. Diquat dibromide at different concentrations is a contact or systemic herbicide? 2. if translocation occurs what is the extent and direction of it. 3. by what concentration it is translocated in hydroponics. It has been stated that diquat dibromide at different dilutions (40-5%) had systemic effect in Robinia pseudo-acacia in the fields. Its translocation has been occurred apically first, and later basipetally. The extent of translocation depended on the concentration. In hydroponics diquat dibromide has crytallized on the leaf surface of Galinsoga parvif lora and all concentrations (40-0.078%) proved lethal. Recognition and application of systemic characteristics of diquat dibromide is reported here for the first time. Improvement of application method is in the focus of our future work.
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Nectar production of quince (Cydonia oblonga Mill.) cultivars
87-94.Views:1253Nectar 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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First results of varios sour cherry cultivar on Oblacsinska as interstocks and Prunus mahaleb rootstocks
87-90.Views:13855At the experiment orchard of the Fruit Research and Extension Institute, Újfehértó, Hungary in spring 2000 a trial was designed included: Erdi bőtermő, Debreceni bőtermő, and Csengődi sour cherry (Prunus avium L) cultivars which were budded at 1999 on Oblacsinska sour cherry (as a dwarf inter stock), which had been budded on Prunus mahaleb seedlings at 1998 with the aim to investigate the dwarfing effects of Oblacsinska sour cherry cultivars on scion cultivars. Trees of each cultivar directly on Prunus mahaleb seedling, severd as controls. Use of Oblacsinska as an interstock reduced the rootstock trunk diameter. Trees of Debreceni bőtermő, and Cseng6di sour cherry cultivars with Oblacsinska interstock were smaller than similar trees grafted directly onto Prunus mahaleb as a rootstock. Trees of Erdi bőtermő grafted on Oblacsinska interstock which buded on Prunus mahaleb were the smallest. Growth of the trees was reduced also by using of the Oblacsinszka as interstock for other examined cultivars.
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Evaluation of crop yield and fruit quality in organic apple production
7-10.Views:4118In this study, crop yield and fruit quality parameters (soluble solid concentration, sugar, total acid, and vitamin C content) of 15 apple cultivars including old, resistant and currently grown cultivars. The highest fruit yield among all 15 cultivars was obtained on CV. Jonagold with 15.5 kg/tree, while the lowest yield was measured on the resistant cultivar Reanda with 8.1 kg/tree. There were no significant differences among the cultivars in fruit diameter ranging from 70 mm in the case of cv. Húsvéti rozmaring to 82 mm for cv. Mutsu. Values of soluble solids concentration of the cultivars varied between 15.5% for cv. Téli Banán and 19.2% for cv. Renora. Sugar content values showed a similar tendency to soluble solids content. The highest and lowest total sugar content was observed on cvs. Jonagold and Renora and cv. Retina with 17% and 12.4%, respectively. Total acid content values ranged between 0.18% and 0.53% for cvs. Jonagold and Remo, respectively. Values of vitamin C content for the 15 apple cultivars varied between 2 mg% and 4 mg% for cv. Retina and cv. Mutsu, respectively.
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Effects of indole-3-butyric acid levels and activated charcoal on rooting of in vitro shoots of apple rootstocks
25-28.Views:603Rooting responses of rootstocks cvs. JTE-F1, M. 26 and MM. 106 were studied to different concentration of IBA in root induction media and to presence of activated charcoal in root elongation media. High rooting rate (>90%) could be achieved in cvs. JTE-H and M. 26, while cv. MM. 106 showed weak rooting ability at each IBA level tested. Increasing IBA content depressed the rooting only in cv. M. 26. Presence of activated charcoal decreased considerable the rooting rate in cv. M. 26 and decreased the number of roots in cvs. JTE-H and M. 26. These cultivars developed longer roots on media containing activated charcoal, while cv. MM. 106 did not showed any reaction for it.
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Some aspects of disease management of cherry leaf spot (Blumeriella jaapii) with special reference to pesticide use
45-49.Views:1036In this review, some aspects of disease management of cherry leaf spot (Blumeriella jaapii) are summarised with special reference to pesticide use. In the first part of the review, we show the non-chemical control approach (e. g. removal of fallen leaves, planting resistant cultivar) against leaf spot. In the second part of the review, the effect of pesticides including fertilizers (urea) and fungicides on cherry leaf spot are discussed. Special attention are given to the fungicides of copper, dodine, captafol, captan, benomil, chlorothalonil, sterol demethylation inhibitors (e.g. fenarimol, fenbuconazole, myclobutanil, tebuconazole), and strobilurins about their effectiveness against cherry leaf spot. In the final part of the review, possibilities of cherry leaf spot control are discussed in integrated and organic cherry orchards.
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What mechanisms are involved in cabbage-clover intercropping and a further proof of the 'host plant quality' hypothesis
47-51.Views:231Over 10 years of field trials show reductions of most of the pests in Brassicas undersown by clover. The pest-reducing effects are due to the 'appropriate / inappropriate landings' hypothesis (Finch, 1996), and the 'host plant quality' hypothesis (Theunissen, 1994). To find out the mechanisms within the 'host plant quality' hypothesis in the most promising intercropping (collards undersown by clover) glasshouse experiments were conducted to see whether intercropping influences the mean relative growth rate, fecundity and time of maturity of Myzus persicae (Sulzer) (Homoptera: Aphididae) a common pest of Brassicas.
The treatment modelling intercropping showed the smallest mean relative growth rate, delayed the maturity and slowed down the growth of cabbages. The treatment modelling monocropping showed the highest mean relative growth rate and the maturity was reached earlier. These results may indicate that intercropping delays the growth of settled aphid populations, giving another proof that in the case of clover undersown cabbages the 'host plant quality' hypothesis is likely to be acting. The differences between treatments where the roots of clover and cabbages were separated and allowed to grow together suggest that the effect is via the roots by competition.
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Farm-scale evaluation of two widely used sanitation practices for reducing primary inoculums of apple scab in organic apple production
15-18.Views:544Effects of two widely used sanitation practices were evaluated at farm-scale level on leaf degradation and primary infection by Venturia inaequalis in an organic apple orchard (Eperjeske) on two apple cultivars (Jonathan and Prima) from 2011 to 2013. The tested sanitation practices were eradication of fallen leaves by collection and disc cultivation. Treatments of eradication of fallen leaves by collection and disc cultivation reduced signifi cantly (P< 0.001) leaf litter density with 70–85 and 40–55%, respectively, compared to untreated plots in both years. Above treatments in the same order reduced spring scab incidence with 40–50, and 10–20%, respectively, compared to untreated plots. Incidence of leaf scab in autumn was not signifi cantly lower (P< 0.05) in the treatments in the years.
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Partial and total rejuvenation pruning of sour cherry trees
11-15.Views:580Sour cherry can be considered as a special fruit species regarding the growing characteristics, as most of the cultivars are characterized by strong balding. With the aging of the tree the inactive (passive) parts of the canopy are increasing steadily, so the productive cropping surface and the yielding capacity decrease significantly. In our experiments partial rejuvenation pruning was carried out in a 12 years old orchard, and total rejuvenation pruning was performed in a 21 years old plantation to regenerate the cropping surface of the trees. Thanks to the latter one the canopy of the sour cherry trees were regenerated during only two years. The yields of the rejuvenated trees in cv. ‘Debreceni bőtermő’ exceeded the yields of the control trees, as in the case of the cvs. ‘Érdi bőtermő’ and ‘Újfehértói fürtös’ approached it. At the same time the total rejuvenation pruning has a positive effect on the fruit size.
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Comparison of Xanthomonas arboricola pv. juglandis isolates from walnut trees grown in Romania and Hungary
65-69.Views:445Among diseases that affect walnut, bacterial blight is considered the most important one in all walnut growing areas both from Hungary and Romania. For the determination of susceptibility/resistance of walnut cultivars in our posterior work planned, 61 bacterial isolates were collected from walnuts showing symptoms of blight, with the purpose of isolating Xanthomonas arboricola pv. juglandis (Xaj). The characteristic Xaj colonies, frequently present as saprophytes in the infected plant tissues, were separated from other bacteria according to their morphology, yellow colour, hydrolysis of starch, and oxidation of glucose. All isolates were tested for pathogenicity by hypersensitive reaction on tobacco leaves (Nicotiana tabacum L.), bean pods (Phaseolus vulgaris L) and unripe nuts (Juglans regia L.). Determination of taxonomy of the selected isolates denotes a possible subdivision (races, biotypes) of Xaj occurring in different geographical areas, API 20NE and API 50CH kits were used. Hungarian and Romanian strains showed a high degree of similarity of carbohydrate utilization but slightly differed from the type strain. All were Cu-sensitive.
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Comparative study of the vegetative and generative organs in pear varieties
21-25.Views:316An assortment of 17 pear varieties was examined in 2006 at Keszthely, Department of Horticulture, Georgicon Faculty of Agriculture, Veszprem University. The selected varieties were planted in 1980, grafted on seedling rootstock and represented the majority of existing pear plantations in Hungary. The main objective was the determination of suitability of the most important varieties for the purpose of intensive growing technologies even when grafted on vigorous seedling rootstock. The most important growing and fruiting characteristics of the varieties have been assessed and evaluated from the point of view of productivity. We stated that the relations of the trunk or the main axis to the lateral branches and fruiting structures are all subject to varietal effects and are valuable indices of the growing character. The quotient of the diameters of trunk and branch should be around 0.3-0.4, and the relative frequency of fruiting structures (Dárda, nyárs, vessző) meaning the ability of branching and regeneration associated with accurate pruning policies are decisive from the point of view of promising success.
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Floral biological studies on pear cultivars in relation to fire blight susceptibility
25-30.Views:416Floral biological characteristics that may influence cultivar susceptibility to fire blight were studied in 10 pear cultivars in two Hungarian orchards from 1999 to 2003. The receptaculo-ovarial, automorphic nectary is usually bigger in tolerant cultivars than in susceptible ones. Nectary stomata are meso- or xeromorphic. Susceptible cultivars tend to have more xeromorphic stomata, where guard cells are located 1-3 cell rows below the epidermis. The size of nectar chambers is usually smaller in susceptible cultivars. Floral nectar, consisting mainly of glucose and fructose, is more abundant and less concentrated if the cultivar is susceptible to fire blight. The amount of chlorogenic acid was higher in the flowers of tolerant cultivars than in susceptible ones.
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Isolation of living sperm cells and in vitro fusion of Torenia fournieri gametes
81-85.Views:195In contrast to most angiosperms, Torenia contains a naked embryo sac and therefore has been considered since many years as an exciting model plant to study the double fertilization process of flowering seed plants. It is thus not surprising that the isolation of protoplasts from the female gametophyte has been reported already 20 years ago by Mol, the isolation of megaspores and megagametophytes has been published by the authors of this manuscript in 1996 and in 1999. The isolation of the male gametophyte and of sperm cells was published by the authors in 2004. The isolation of viable Torenia sperm cells is a crucial part of the elaboration of an in vitro fertilization system. Torenia sperm cells were isolated from in vivo — in vitro cultured pollen tubes. In this system pollen tubes first grow inside a cut style then follow their elongation in a solid isolation medium. The medium contained agarose in order to detain pollen tube contents. Released sperm cells and enzymatically isolated egg cells were collected and handled using glass micropipettes and transmitted to an electrofusion apparatus or polyethylene glycol containing media for fusion probes.
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Preliminary characterization of the self-incompatibility genotypes of European plum (Prunus domestica L.) cultivars
23-26.Views:521European plum is an important fruit crop with complex, hexaploid genome of unknown origin. The characterization of the selfincompatibility (S) locus of 16 European plum cultivars was carried out using the PaConsI-F primer in combination with the EM-PC1consRD primer for the first intron and the EM-PC2consFD and EM-PC3consRD primers for the second intron amplification. Altogether, 18 different alleles were scored indicating high genetic diversity. These alleles were labelled using alphabetical codes from SA to SS. We identified 5 different alleles in 9 cultivars, 4 alleles in 5 cultivars, while 3 alleles were shown in two of the assayed cultivars. A total of 16 different S-genotypes were assigned, and discrimination of all plum cultivars was successful based on their unique S-genotypes. However, further research is required to reliably identify the S-alleles based on their DNA sequence and clarify complete S-genotypes.
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Sunburn incidence of apples is affected by rootstocks and fruit position within the canopy but not by fruit position on the cluster
45-51.Views:1434Authors investigated sunburn incidence of apples on the combinations of three different growth inducing rootstocks (M.9,MM.106 and seedling) and five varieties (‘Smoothee’, ‘Golden Reinders’, ‘Granny Smith’, ‘Gloster’ and ‘Jonagold Jonica’). Symptoms were classified as sunburn browning, sunburn necrosis and photooxidative sunburn. The frequency of symptoms was recorded at various parts of the canopy (N, E,W, S, and lower canopy, upper canopy) and on the cluster (terminal, lateral). Cultivar susceptibility varied between 0.30 and 5.65% on M.9 rootstock, ‘Granny Smith’ seemed to be the most susceptible cultivar whereas relatively low percentage of damaged fruit was observed for ‘Gloster’. On MM.106 and seedling rootstocks, damage level was significantly lower than on M.9. Remarkable differences were not observed in the share of the three sunburn types between cultivars. The most common symptom observed was sunburn browning. Far less fruit was affected by sunburn necrosis and photooxidative sunburn. Photooxidative sunburn symptoms were not found on ‘Granny Smith’ and ‘Gloster’ fruits on MM.106 rootstock. Latter cultivar did not show sunburn necrosis symptoms either. With increasing growing vigor of the rootstocks the share of sunburn browning increased. Fruits with sunburn symptoms were found in a great majority on theW quadrant of the trees. This was true for all cultivars. Remarkable differences in the location within the canopy of affected fruits between the three types of sunburn were not observed. Specific distribution of sunburned fruit was observed along the vertical axis of the canopy, too. Most of the damaged fruit were found in the upper canopy. This is particularly true for trees on vigorous stocks such as MM.106 and seedling. On M.9 rootstock, depending on cultivars 5.9 to 38.9% of sunburned fruit was located in the lower canopy. Most common symptom in the lower canopy was the sunburn browning, however symptoms of sunburn necrosis were not found at lower canopy level. Low rate of photooxidative sunburn was observed such lower canopy conditions. Sunburn incidence was very similar on king or side fruit. Significant differences were not found in the share of each sunburn types between fruit positions on the cluster. This was not influenced by rootstocks either.
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Callus induction on standard type Cymbidium cultivars
108-110.Views:346Tissue cultured Cymbidium PLBs (protocormlike body) were used as starting material to induce embryogenic callus which could serve as objects of genetic transformation. We obtained callus using two methods. The first method was culturing the PLB segments for one month in liquid MS medium in the presence of 0.5 mg/1 benzyladenine and 0.05 mg/1 naphtylacetic acid followed by cultivation on the same composition solid medium with 0.5 g/l activated charcoal for an additional month. Callus formation was observed on 30% of the explants. The second way was to propagate the PLB segments on solid MS medium supplemented with 1 mg/1 thidiazuron. In these cultures we also observed callus formation on 20% of the explants.
