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Anatomical study of the leaves and petioles of scab resistant and susceptible apple cultivars
53-57.Views:401Anatomic studies have been performed on the leaf blade, petiole and annual shoot on six apple cultivars by means of scanning electron as well as light microscope. Four of the cultivars examined are resistant to scab (Florina, Freedom, MR-10, MR-11), whereas two of them are susceptible (Jonathan and Idared). Preliminary results suggest that differences in the width of cross sections of leaf blades, in hairyness, in the shape and size of epidermal cells, moreover, in the cross sections of petioles and shoots are considerable. Some of the anatomical properties seem to be correlated with scab resistance or susceptility of the respective cultivars. Therefore, further studies extending to other cultivars may corroborate our claims to find causal relations between anatomical traits of the leaves and disease, especially scab resistance of apple cultivars.
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Preliminary evaluation of breeding perspectives of Ukrainian sweet cherry cultivars: nutraceutical properties and self-incompatibility
7-11.Views:1201Some traditional sweet cherry cultivars of Ukrainian origin may represent perspective material for Hungarian cherry breeding. A total of eight cultivars analysed represent great diversity in several phenotypic traits including fruit ripening time or fruit flesh colour. Considerable differences in the anthocyanin content may result in different antioxidant capacity of fruits. In the present study, we used ferric reducing antioxidant power (FRAP) and total phenolic content (TPC) assays to characterize fruits’ nutraceutical properties. These values were compared with the respective values measured for eight commercial cultivars grown in Hungary. The average of FRAP and TPC values was higher for the Ukrainian cherries compared with commercial cultivars suggesting they might be included in functional breeding programs. Since, cherry is a self-incompatible species, the determination of S-genotype is required for both breeding and successful cultivar association in commercial orchards. Complete or partial S-genotypes were determined for 5 and 3 cultivars, respectively.
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Effect of intensity of bee visitation and the foraging behaviour of honeybees on the fruit set and yield of apple (Malus domestica Borkh.)
31-39.Views:403Based on the results of our experiments, both the relative and the effective intensity of bee visitation were rather different depending on the cultivars as well as the time of the day. While it varied between relatively extreme values (40-80%) in the morning for the varieties examined, there were much smaller differences between the intensity of bee visitation at the afternoon, because the relative bee visitation attained 70-90% at each cultivar. These results showed that the differences arising from intensity of bee visitation of different cultivars should be taken into consideration more carefully in the morning in orchard planning and in estimating the number of honeybee colonies required.
The results showed that the greatest percentage of fruit set and the highest number of viable seeds per fruit were measured on branches of those cultivars that were most frequently visited by pure pollen gatherer bees as well as by bees collecting both nectar and pollen (mixed behaviour). The effect of pure pollen gatherers and of bees with mixed behaviour was highly significant from the statistical point of view on the fruit set and the number of viable seeds per fruit.
Those bees that were sucking nectar only from apple flowers did not proved to be effective pollinators at all. Relationship between their number and the fruit set as well as the number of viable seed per fruit were not significant because the coefficient of correlation was close to nil.
The ratio of side worker nectar gatherers was negatively correlated with the fruit set and the seed content of fruits of apple cultivars examined at both of our experimental sites, at Mosonmagyaróvár and Feketeerdő as well. The presence of side worker nectar gatherers resulted in higher decrease of fruit set and seed content of fruits at Feketeerd6 than at Mosonmagyaróvár, especially in the morning.
The effect of flower visiting intensity by other pollinating insects was found to be fairly variable according to the time of the day. In the morning they had no effect on the fruit set as well as on the seed content of fruits either at Mosonmagyaróvár or at Feketeerdo. However, at the afternoon, when their intensity was greater, the correlation was a bit stronger.
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Nectar production of quince (Cydonia oblonga Mill.) cultivars
87-94.Views:1502Nectar 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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Simultaneousness of reproductive organs of sour cherry cultivars adaptable to Iranian climatic condition
25-31.Views:1172Observations were made on simultaneousness of pollen shedding and stigma viability ratio, to clarify the phenology of reproductive organs of nine economically important sour cherry (Prunus cerasus L.) cultivars (‘Érdi bôtermô‘, ‘Debreceni bőtermő‘, ‘Csengődi‘, ‘Kántorjánosi 3‘, ‘Újfehértói fürtös‘, ‘Petri‘, ‘Eva‘, ‘Oblascinszka‘, and ‘Pándy 279’). The main aim was investigation the possible influence of environmental cues in timing and development of phenophases and also responses of different cultivars to seasonal cues. Likely effects of climatic changes on phenological development patterns were also considered. Results showed 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 a maximum 3 day difference in the blooming length of different directions 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 the tree. The pollen shedding period and stigma viability ratio were synchronous. Pollen shedding phenomenon simultaneously occurred with the secretary activities of stigmas in all examined cultivars. Distribution of pollen shedding over the secretary activity of stigmas is almost good. In all five cultivars maximum pollen shedding occurred when the temperature was high during the day. In general the results of this experiment and our previous studies clearly demonstrate that the Pándy groups not recommended for plantation in new orchards of Iran.
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Study on the micronutrient content of soil and leaf of an organic apple orchard in Eastern Hungary
7-11.Views:966The aim of our study was to investigate the relationship between micronutrient content of soil and leaf in an organic apple orchard. The experiment was carried out at the Experimental Site of the University of Debrecen, Centre of Agricultural Sciences at Pallag in an apple cultivar collection in Eastern Hungary in 2002-2004. The soil sampling was carried out twice per year, at the beginning and the end of the vegetation period in 2002, 2003 and 2004, respectively. The micronutrient content of leaf of seven apple cultivars (Jonagold, Mutsu, Idared, Red Elstar, Egri piros, Reka, Remo) was studied according to phenological phases of apple (April — September) to investigate the dynamism of plant nutrient uptake.
It was found that results of leaf analysis correlated with the obtained results of soil. According to the data of July, manganese and copper content of leaf is in the 'favourable' but zinc is the 'low' range of nutrient supply category. Moreover, there were significant differences in the micronutrient content of leaf among cultivars. From our results it is evident that more reliable data were obtained for fruit nutrition by determining of micronutrient content of soil and plant and calculate their ratios as well.
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Some structural characteristics of the flowers of apple cultivars with different susceptibilty to fire blight
21-23.Views:328Several morphological characters of the hypanthium (size and form of the surface, the shape of the hypanthium) and anatomical traits (number and pattern of stomata) of apple cultivars (Malus domestica L.) with different susceptibility to fire blight were studied. The size of hypantium surface was calculated by modelling the hypanthium with a truncated cone. Three types of hypanthium surface form have been revealed: straight, convex and a complex "shouldered" one. The angle between the style and the wall of the hypanthium was narrow or wide. The stomata on the hypanthium surface can be arranged in a zone in the middle third of the hypanthium or dispersed more or less evenly. The number of stomata/flower substantially differed among the cultivars examined. The highest stomata number was detected in the flowers of the tolerant cultivar (Freedom)
No single characteristics of the hypanthium could convincingly be correlated with susceptibility to fire blight. We suggest, however, that combination of morphological properties that sustain moist environment in the hypanthium contribute to susceptibility.
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Skin colour and softening synchronization during ripening of three avocado cultivars
126-133.Views:58Skin colour-softening de-synchronization during the early season remains a major quality concern in ‘Hass’ avocado, leading to consumer dissatisfaction and market losses. This study evaluated whether Hass-type cultivars ‘Carmen’ and ‘Maluma’ exhibit de-synchronization between skin colour and mesocarp softening as compared to ‘Hass’ avocado. The study was conducted using fruit harvested from a ZZ2 Moeketsi commercial farm in Tzaneen, Limpopo, South Africa. The ‘Carmen’ and ‘Maluma’ cultivars were harvested in April 2024, while the ‘Hass’ cultivar was harvested in May 2024. The harvested fruits were stored at 5.5 °C for 28 days. After cold storage, fruit were held at ambient temperature to induce ripening. Firmness declined significantly in all cultivars (p < 0.001), with ‘Carmen’ softening earlier and ‘Maluma’ showing a gradual softening pattern. Skin colour changed from green to purple and black; however, colour development was more pronounced and closely aligned with softening in ‘Carmen’ and ‘Maluma’. Chlorophyll and carotenoids decreased, whereas anthocyanin increased during ripening, with a stronger correlation between colour, firmness, and pigment changes in ‘Carmen’ and ‘Maluma’. These results indicate better skin colour-softening synchronisation in ‘Carmen’ and ‘Maluma’, supporting their suitability for early season export programs.
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Determination of the cold tolerance off sour cherry cultivars with frost treatments in climatic chamber
49-54.Views:1090Nowadays, sour cherry buds can be seriously damaged by spring and winter frosts. Unlike other fruit species threatened by high frost damage, sour cherry cultivars have not been assessed for frost tolerance. The aim of .our survey was to establish the relative cold tolerance of the Hungarian cultivars after treatment in a climatic chamber, and to optimize the methodology formerly elaborated for the frost treatment of apricot. Fourteen cultivars of Hungarian sour cherry (Prunus cerasus) were used in the experiments, which spanned the winters of 2005/2006 and 2006/2007. Our data were used to rank cultivars in two groups according to their levels of cold resistance. We also recommend critical temperatures and treatment times for the testing of sour cherry cultivar resistance to cold in climatic chambers.
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Comparative evaluation of different valerian (Valeriana officinalis L.) lines
63-66.Views:304Research project to establish a Hungarian valerian cultivar with acceptable production, biological and chemical properties of five promising Valeriana officinalis L. lines were studied. The populations were not homogeneous especially with regard to leaf shape and colour. Line 'IV/1' showed the strongest vigour, was characterised by the highest root-yield (381.79 g/plant), volatile-oil (0.60 m1/100 g) and valtrat content (1.15%). However, the highest valeric-acid content (0.20%) was measured in another line, 'I/5'. According to our results, the above-mentioned lines (1/5', 'IV/1') could be the basic material of breeding work in the future.
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Disease threshold for cherry leaf spot incidence on commercial sweet cherry cultivars
52-54.Views:717The aim of this study was to demonstrate the 10% threshold level for cherry leaf spot incidence on 23 commercial sweet cherry cultivars in two training systems. Twenty three cherry cultivars were evaluated in the two training systems with a spacing of 4 x 1 m and with a spacing of 2 x 5 m. Results showed that leaves of many cultivars were heavily infected, e.g. cultivars (cvs) ’Biggareau Burlat’, ’Sunburst’, while others showed low disease incidence e.g. cvs ’Celeste’ and ’Blaze Star’. According to the 10 % threshold level, cv ’Celeste’ proved to be the most resistant cultivar to leaf infection, while cv ’Münchebergi korai’ exceeded extremely the 10% threshold level. Leaf spot incidence was affected by training system on most cultivars. Thirteen cultivars had less than 10% infection in the 4 x 1 m spacing (i.e. they did not reach the 10% disease threshold level). At the same time, only 3 cultivars showed less than 10% infection in the 5 x 2 m spacing.
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Response of alternate bearing of “Badamy sefid” Pistachio cultivar to foliar application of some macro and micro elements
109-112.Views:383Response of “Badamy sefid” Pistachio trees to spraying of fertilizer was studied over two years (2006–2007). The boron and zinc fertilizer were used just on swelling time of female flower bud in compare to no fertilization (control). Also nutritional solution combined of nitrogen (400 ppm), phosphorus (P2O5) (380 ppm), potasium (K2O) (520 ppm), Fe (5 ppm), Cu (2 ppm), Zn (2 ppm), Mn (2 ppm) in 1000 liter water per hectare sprayed at first week of May, third week of June and July). The concentration of some macro and micro elements in flower bud and in leaves, also productivity (g/shoot sectional area) mean nut weight, fresh weight of nut per cm2 branch cross sectional area, blanks nuts %, non-split nut %, new shoot growth length after cessation of growth and remained flower bud (%) at the next spring were recorded for the different treatments. The results showed that boron and zinc concentration increased in the bud of sprayed trees in compare to control. Application of nutritional solution decreased the flower bud abscission, also resulted in increased vegetative growth, nut weight, and productivity of trees. In conclusion, spraying of fertilizers in the suitable time to the pistachio trees might be a useful method in decreasing flower bud abscission and mitigating the alternate bearing.
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The role of pruning in the intensification of plum production
83-86.Views:558In an orchard planted in the spring of 1997, four kinds of spacing have been applied (4.0 m x 1.5 m, 4.0 m x 2.0 m, 5.0 m x 2.5 in and 6.0 m x 3.0 m). Four cultivars (‘Cacanska lepotica', Stanley' ‘Bluefre' and ‘President') grafted on Myrobalan rootstock were studied in the experiment aimed to explore the performance of plums under different spacing and training conditions.
It could be stated that the trees grown on vigorous rootstock are prone to be cultivated much more intensely (smaller tree size, higher tree density) by the consequent use of green pruning technique. The most favourable economic combination (yield and labour costs) was found to be: 4.0 in x 2.0 in and 5.0 x 2.5 in (800-1200 tree/hectare), whereas the most adapted was the cultivar: 'Stanley'.
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Susceptibility of some traditional pear cultivars of Hungarian and foreign origin to the pathogenic bacterium Erwinia amylovora
41-45.Views:329Fire blight, a disease caused by the bacterium Erwinia amylovora (Burrill) Winslow et al., has been causing serious damage in Hungarian pear plantations since 1996. A prospective control measure could be the use of resistant cultivars. For that purpose ten pear cultivars have been tested under laboratory and greenhouse conditions for resistance to Erwinia amylovora strains collected in Hungary. Six of these cultivars are Hungarian ones of unknown origin, while four are traditional old varieties. Resistant cultivars should serve as germplasm for future breeding. Inoculations were made with a mixture of different pear isolates of the bacteria collected from various growing regions of Hungary (Ea 21, 23), at a density of 5x108 cells/ml. Susceptibility/resistance has been assessed on the basis of intensity of blight symptoms observed on shoots, flower parts and fruits. Cultivars were assigned to three susceptibility groups (low, moderate and high). Complete resistance was not found among the cultivars tested. The highest level of resistance was found in cultivar 'Kieffer', while the other cultivars displayed either moderate or high susceptibility to infection.
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Evaluation of the vegetative and generative performance of new apple cultivars in the Nyírség region
39-44.Views:491In this paper we examine apple varieties, which are planted expansively in the development apple orchards of the Western- European countries, but about its production characteristics we don’t have or just few practical experiences in Hungary. These varieties can be described with regular and high yields, aesthetic and alluring appearance in their origin places, what ensure profitable producing for the growers. Under the Hungarian climate which tends to be often extreme (hard cold winters, late spring frosts, summer drought, heat stress) these varieties may behave differently, so before the substantial planting it is expedient to carry out variety evaluations to avoid the later failures. The place of our experiments is located in the Nyírség representing adequately the ecological conditions of the surrounding areas, so the gained results can be adapted easily in the biggest apple production site of Hungary. Regarding the vegetative and the generative parameters of the 14 examined varieties (’Gala Venus Fengal’, ’Gala Decarli-Fendeca’, ’Galaval’, ’Jugala’, ’Gala Schnitzer (S) Schniga’, ’Red Cap Valtod (S)’, ’Early Red One’, ’Jeromine’, ’Crimson Crisp (Co-op 39)’, ’Red Topaz’, ’Wilton’s Red Jonaprince’, ’Red Idared’, ’Fuji September Wonder’, club cultivar) we found significant differences. The ratio of the thickness of trunk and the main branches showed that the trees have an optimal canopy structure in accordance with the Zahn principles, so they are in harmonious growing balance. The ‘Gala’ sport trained to slender spindle produced the highest yields, while the ‘Fuji’ and the ‘Red Delicious’ sport trained to super spindle can be described with the lowest values. All the cultivars reached the eating quality (65-70 mm), from which the ’Red Idared’, the ’Red Jonaprince’ and the ’Red Cap’ produced outstanding fruit size (81-85 mm).
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Fire blight (Erwinia amylovora) resistance in apple varieties associated with molecular markers
53-57.Views:527The invasive bacterial disease fire blight, caused by Erwinia amylovora has the potential to destroy fruit tree orchards all over Europe. Effective plant protection methods are lacking in many countries, highlighting the increasing importance placed on identification of germplasm with heritable disease resistance. Recent l y. a promising QTL (quantitative trait locus) was identified on linkage group 7 in the apple cultivar 'Fiesta· which is derived from ·cox's Orange Pippin' . I n the present study, 144 Swedish and foreign apple cultivars were analysed with the SCAR markers AE I 0-375 and GE-8019. which flank-. this QTL. Twenty-nine of the analysed cultivars had both markers. 78 had either AE I 0-375 or GE-8019, and 37 cultivars did not carry an) of the two markers. Seventeen cultivars. 7 with both markers and I 0 not having either of the two markers, were then inocoluted with the bacterium in a 4uaran1i ne greenhouse test. Cultivars carrying both DNA markers were significantly less susceptible than cultivars lacking the markers, P<0.001. Cultivars that were most resistant had both markers and had 'Cox· in their pedigree. Unrelated cultivars with the markers may still lack the QTL.
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Metaxenic pollen effect of scab resistant apple cultivars on the fruit of apple
47-52.Views:431As a part of an apple breeding program, we have examined the pollen effect on the fruit appearance and inner quality of different apple cultivars in the Corvinus University of Budapest Department of Fruit Science. Five apple cultivars ('Golden Reinders', 'Regal Prince', 'Rewena', 'Renora', 'Idared') have been crossed by the pollen of some new and some traditional cultivars in our experiment. The measurements were carried out in the analytic and fruit examining laboratory of the Department of Fruit Science. The diameter, height and stem length were measured by digital caliper. We have also examined the squash ratio, soluble solid- and acidic content. Sugar content was calculated by a schedule released by the International Sugar Committee (ISC). From the sugar- and acidic content, we could also count the Pomona-value.
We have observed interesting effects according to some attributes in some crossing combinations with the help of statistical analysis. Crossing 'Golden Delicious' with 'Freedom', 'Prima', and 'Baujade' have resulted in smaller fruit size than other combinations. No significant differences could be observed on `Golden Reinders' fruits according to metaxenic coloration in the year of the examination. On the other hand the color modifying effect of pollen donating cultivars have manifested on the red fruits of 'Regal Prince' (Gala Must). `Freedom' as a pollen donating cultivar has resulted outstanding value in our consistency measurements. Squash ratio was the highest in combinations pollinated by 'Prima' and `Reglindis'. We have noticed balanced values when measuring inner qualities, only `Reka' has caused lower acidic content. Significant differences have been found in combinations according to the number of frivolous seeds. No frivolous seeds were found in the combinations 'Golden Reinders' x 'Freedom' and 'Idared' x 'Prima'. Almost two frivolous seeds were found in the fruits of the combination 'Renora' x 'Sóvári' in average.
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The fertilization problems of cultivated red- and black currant varieties in Hungary
38-40.Views:297Small fruits have a modest share in the fruit production of Hungarys. Red currant was grown traditionally in home gardens 60-70 years ago. Commercial production was established only in the surroundings of some town. The black currant was unknown until after Wold War II. An important change occured in small fruit production in the 1950s. Socialist countries, which had cheaper labour power, made efforts to meet these demands. In this time we produced 25.000 t.
Presently the country produces 13-15.000 tons currant fruit yearly 60% from this is black currant, which has a better market. It is our own interest to make our currant production more profitable. The currant is the second most widely cultivated soft fruit. Our product is disposed mostly on EU markets.
There was no breeding activity in this field in Hungary earlier. Cultivars used were mostly of foreign origin (W. European; Boskoop Giant, Silvergieter, Wellington XXX, Russian; Altaiskaya Desertnaya, Neosupaiuschaiasya, N. European; Brikltorp, Ojebyn). Besides well-known advantageous this cultivars have also some defects mainly unfavourable—adaptation to climatic conditions, which caused fertilisation problems, reduced the fruit set and uneven growth with decreased yields (Dénes & Porpáczy, 1999). About 140 black currant cultivars were investigated during the last four decades in our variety trials and only four of them were introduced with satisfying yielding capacity (3.5-5.5 t/ha).
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Comparative analysis of sour cherry cultivars on their ecological and biological indicators
7-28.Views:667Sour cherries developed in the northern hemisphere, an alloploid hybrid of dwarf sour cherries (Prunus fruticosa) and bird cherries (P. avium), born in the confluence of the two species. However, the ecological and, above all, cold tolerance of the ancestor of cultivated sour cherries is higher than that of wild cherries (De Candolle, 1894; Rehder, 1954; Terpó, 1974; Iezzoni et al., 1991; Faust & Surányi, 1997). The cultivation limits are in the northern hemisphere 38-44. degree. The Carpathian Basin, the Balkans and Asia Minor are considered to be the main birthplaces for sour cherries. The genetic and morphological diversity of sour cherries is greater than that of the basic species (Iezzoni et al. 1991; Faust & Surányi, 1997). In the study, 472 sour cherry cultivars were compared based on 7 relative ecological indicators and 3 biological values. Compared to other Prunus species, we mostly found less variability in sour cherries - not counting their salt tolerance (SB). The partial similarity between open pollination (OP), frost tolerance (FR) and disease resistance (DR) - partly true in terms of varieties, but also reflected the effects of purposeful breeding and selection. The cultivars together - in comparison, showed balance, but in the highlighting, the differences of the 3 cultivar groups became significant. Indeed, the differences between the species of the former Hungarian cultural flora are clearly different (Surányi, 2004), which is also the case when comparing a large number of apricot (Surányi, 2014), plum (Surányi, 2015) and peach (Surányi, 2020) varieties.
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Comparative anatomical study of leaf tissues of scab resistant and susceptible apple cultivars
43-45.Views:384According to previous studies some anatomical features seem to be connected with resistance or susceptibility to scab caused by Venturia ineaqulis (Cke./Wint.) in case of a given cultivar. Study of leaf anatomy of three scab resistant (‘Prima’, ‘Florina’, MR–12) and two susceptible (‘Watson Jonathan’, ‘Golden Delicious Reinders’) apple cultivars have been made. Preserved preparations made of leaves has been studied by light microscope. Studied parameters were: thickness of leaf blade, thickness of palisade and spongy parenchyma, thickness of epidermal cells, thickness of the cuticle. By measuring leaf thickness and epidermal cell thickness visible differences appeared in certain cultivars, while most conspicuous difference has been shown in thickness of the cuticle.
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The impact of location, row direction, plant density and rootstock on the sunburn damage of apple cultivars
19-30.Views:1341The effect of row direction (N-S, E-W), plant density (conventional and intensive) and rootstock (M9, MM106 and crab apple) on the sensitivity of 41 apple cultivars to sunburn injury was studied at 6 locations (Derecske, Kálmánáaza, Nagykutas, Nagylapos, Siófok, Tornyospálca).
During the observations the cultivars had rootstock-specific properties in respect of sunburn-susceptibility. Accordingly, the injury was decreased in the order: M9, MM106 and seedling rootstocks. The differences in sensitivity depend on the canopy of trees, caused finally by the growing vigour of rootstocks. Accordingly, the highest value of sunburn injury was observed on M9 rootstock, because this rootstock has a dwarfing effect upon the scion cultivars. Thus, vegetative area of these trees grow very slowly and the foliage is not enough compact to protect the fruit from solar radiation. The size and density of the foliage increased in the order: M9, MM 106 and crab apple seedling as rootstock. Moreover, relationships were demonstrated between the diameter of upper part of the crown, the leaf area, the number of fruits per tree and the injury of sunburn.
Authors categorized the cultivars in respect of values of sunburn incidence: 1. „Not sensitive", II. „Moderately sensitive" and HI. „Strongly sensitive" categories were constituted. Generally, Topaz and Gala cultivars showed low damage (or were free from symptoms), in contrast to this, Golden mutants suffered relatively much. The most sensitive cultivar was Jonica on all the three rootstocks. We searched for relationship between the fruit quality parameters and the frequency of sunburn. Significant correlation was found in the cases of fruit size and the extent of cover-colour. The latter is interpreted with the fact that the best coloured fruits are found on the periphery of crown as a consequence of more intense irradiation.
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Continuous and discontinuous nectar secretion in some pear cultivars
77-79.Views:238Hourly nectar secretion was studied in five pear cultivars between 1997-1999. Some cultivars (e.g. ‘Csákvári téli') secreted nectar continuously during the whole day, offering both nectar and pollen for pollinating insects. Discontinuous secretion (e.g. cvs. ‘Viki', `Nyárig tartó 6/19') is less advantageous from the viewpoint of insect attraction. In some cases, however, discontinuity or continuity of nectar secretion varied even within a cultivar (e.g. 'Solymári cukor', ’Jó szürke’) in different years.
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Old Hungarian grapevine cultivars and their relations characterized with microsatellite markers
27-31.Views:551Thirty-one old Hungarian grapevine (Vitis vinifera L.) cultivars were investigated on 7 microsatellite loci to characterize them, to separate the cultivars from synonym names, and to confirm parent-offspring connections. Conculta (group of cultivars or bud sports) members, such as `Goher' and Tajor' representatives, were studied to find a suitable locus for the separation. Synonyms, conculta members, subcultivars and clones of Turmine, which was the most important cultivar of Tokaj, were also analyzed to separate the members of the different taxonomic levels. Pedigree of 'Kiralyleanyka' was examined to find the missing ancestor, because the parent-offspring connection between the natural hybrid and `Koverszolo' is questionable.
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The effect of nectar production to the gathering behaviour of honeybees and to the foraging activity of wild bees at apple flowers
45-57.Views:458Intensity of bee visitation (honeybees and wild bees), foraging behaviour of honeybees and nectar parameters (nectar production, sugar concentration, sugar content in nectars) were inspected at 18 apple cultivars for three consecutive years. Honeybee visitation was calculated to be some 3.07 bee visits at a single apple flower a day but wild bee activity was very low, only some 0.11 wild bee visits per flower per day.
The nectar production (nectar content) of apple flowers was fairly different according to the cultivars and the nectar production (nectar content) of flowers was negatively correlated with the sugar concentration in nectar. Interestingly, at the majority of the inspected 18 cultivars the nectar production has shown minor or no changes in the morning and at the afternoon. The nectar production (nectar content) of flowers clearly encouraged the total bee activity at the inspected cultivars (r = 0.54). Bees visited abundant nectars with greater sugar concentration most intensely than lees abundant nectars with smaller sugar concentration.
Nectar parameters, however, affected the activity of honeybees with different types of gathering behaviour in different way. More intense activity by pollen gatherer and mixed behaviour honeybees was observed at cultivars producing abundant nectar (pollen gatherers: r = 0.65, mixed behaviour: r = 0.79). The activity of pollen gatherer honeybees and of mixed behaviour bees, on the other hand, was negatively correlated to the sugar concentration in nectar (pollen gatherers: r = -0.51, mixed behaviour: r = -0.73). This can be explained by the fact that their behaviour was much more affected by the amount of pollen than by any nectar parameters. Accordingly, "mixed behaviour honeybees" should probably rather be called as "pollen gatherers with nectar load" instead of "nectar gatherers with pollen load", as widely used in literature. The activity of ineffective side worker nectar gatherers was greatly encouraged by the sugar concentration in nectar (p = 0.63), similarly to the pure (top) nectar gatherer honeybees (r = 0.72). There was a negative relationship between the nectar production (nectar content) of flowers and the activity of these behaviour classes (nectar gatherers: r = -0.47, side workers: r = -0.36).
Concluding the findings we can state that the activity of pollen gatherers and mixed behaviour honeybees is strongly encouraged by greater nectar production (greater nectar content) of apple flowers. Their activity, however, is mostly dependent firstly on the amount of pollen. This is the reason why the sugar concentration is in a negative relationship to the activity of pure pollen gatherers and mixed behaviour bee. On the other hand, pure nectar gatherers and side worker nectar gatherers are greatly encouraged by the sugar concentration of apple nectar the amount of nectar was not a definite influence on their activity.
Side worker honeybees occurred at each cultivar inspected, however, their ratio varied widely among cultivars. So we can draw the conclusion that, in contradiction with earlier believes, side worker nectar gathering is a general phenomenon at apple flowers. The activity of side workers depends first of all on the relative position of stamens and petals; however, low sugar concentration of nectars can probably moderate their activity but probably do not affect pollen gatherers and mixed behaviour bees.
Wild bee visitation was very low; the wild bee species observed (Osmia cornuta, Andrena flavipes, Anthophora acervorum, Bombus terrestris, Bombus lapidarius and Halictus simplex) comprised some 3.44 per cent of the total bee visitation at apple flowers only. Wild bee visitation was in a positive correlation with the nectar production (nectar amount) of flowers (r = 0,4) and with the sugar content of nectar (r = 0.46) but it was negatively correlated with the sugar concentration in nectar (r = -0,27).
Our result calls the attention to the importance of nectar parameters in the effective honeybee pollination of apple plantations. Most effective pollinating activity of honeybees can be expected in plantations with cultivars of high nectar production because this feature seem so encourage the activity of those behaviour classes (pure pollen gatherers and mixed behaviour bees) that are the most effective pollinating agents among honeybees.
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Varietal variations in fruit quality parameters in strawberry (Fragaria×ananassa) harvested at different stages of color development
102-114.Views:70Present investigation reports the fruit quality of five strawberry cultivars (‘Rania’, ‘Winter Dawn’, ‘Winter Star’, ‘Camarose’ and ‘Navelia’) harvested at different stages of color development. These cultivars showed significant variations in their chemical composition. The highest and significant values of fruit weight, hue angle and total sugars were recorded in ‘Winter Star’ cultivar at full red stage. Total phenolics and ascorbic acid content were higher in ‘Camarose’ as compared to other cultivars. These parameters and reducing sugar content in strawberry fruits showed a direct relationship with DPPH radical scavenging activity. ‘Winter Star’ exhibited highest anthocyanin content form 25% red to full ripe red stage of fruit color development with most intensive color. Total soluble sugars, reducing sugars, pH, °Brix values increased from green to full red stage whereas titratable acidity showed the reverse trend. These cultivars showed significant differences in their physicochemical and biochemical composition at different stages of ripening in agroclimatic conditions of Punjab area of northwest India.
