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• Severely pollen-limited fruit set in a pear (Pyrus communis) orchard revealed by yield assessments and DNA-based paternity assignment of seedlings

  67-74.

  H. Mattison

  J. Sehic

  H. Nybom

  Views:

  162

  In commercial fruit tree orchards, consistently high yields are necessary for a durable economy. The Swedish pear cultivar 'Carola' has been noted for low setting in some orchards, possibly due to insufficient pollination. In this study, fruit set was evaluated in a research orchard where `Carola' had been planted together with four potential pollinators. Total yield and number of fruits was noted during three and four years, respectively. In 2003, seeds were germinated from the harvested `Carola' fruits, and the paternity of three seedlings from 50 trees was determined with RAPD analysis. 'Clapp's Favourite' had sired 39.6% of the seedlings, closely followed by `Seigneur d'Esperen' (30.7%) and 'Clara Frijs' (26.7%) whereas 'Skanskt sockerparon' only sired 1.1% of the seedlings. The remaining 2.3% appeared to have been derived by selfing. Pollen-limited seed set was indicated at surprisingly short distances; accumulated number of fruits on the `Carola' trees was significantly higher when separated by only 2 m from one of the two most efficient pollinators, 'Clapp's Favourite' or 'Seigneur d'Esperen‘, compared to trees 4—l0 in away in the same row. Number of viable seeds per fruit was also higher in fruits from trees immediately adjacent to the pollinators, suggesting an effect of improved pollination success. The importance of very short inter-cultivar distances for efficient pollen transfer became even more clear when comparisons involved the true pollination distances as determined by RAPD; the accumulated yields decreased linearly from 55 kg at a 2 in distance to only 17 kg at 13 m.

• Variability of the data indicating the fertility of different plum varieties

  51-55.

  Z. Szabó

  J. Nyéki

  Views:

  157

  Self-fertility and fertility at conditions of open pollination in plum varieties is strictly determined by genetic factors. However, rates of fruit set are highly variable according to growing sites as well as to seasons, which may result from a couple of inner and outer conditions, but mainly from the method applied in seizing the facts of fertility in the experiments planned including the number of replications of treatments. During three successive years, 4-16 trees of each of the four plum varieties have been selected and 16-64 branches were tagged either for checking their fertility as pollinated freely or isolated excluding the access of foreign pollen. The data of fruit set have been processed in order to determine the variability of the data, subsequently, the number of replications necessary to make reliable decisions. Both autogamy and open pollination displayed multiple differences between branches and trees studied.

  A number of 20 branches are needed yearly for each variety, the branches should be distributed on 5 trees at least for checking the autogamy, whereas on 10 trees for the results of open pollination. Each variety and treatment should be represented in three seasons, at least because of the different weather conditions.

• Self fertility of pear varieties conditioned by natural self pollination (autogamy)

  110-113.

  J. Nyéki

  M. Soltész

  J. Iváncsics

  Views:

  164

  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.

• Floral biology of tree fruit rootstocks

  153-161.

  K. Hrotkó

  Z. Erdős

  Views:

  152

  The modern nursery industry requires seed sources of a high quality and regular quantity year by year. Besides the seed sources of processed cultivars (Bartlett pear, Shipley, Elberta peach) special seed orchards are planted with selected seed trees producing high quality and genetically determined seed (hybrid seed or inbred lines). Seedlings are still the most common commercial source of rootstocks for stone fruits (almond, apricot, peach, plum, prune and walnut). Although clonal rootstocks are spreading, usage of seedlings is still predominant at stone fruits and nuts. For successful seed production and planning of seed orchard the knowledge on floral biology, flower fertility, pollination, blossom time of trees (selected clone or cultivars) used for seed production is essential. In this field very little systematic research was carried out most of the papers were published in the second half of the 20th century. Our mini review gives an overview on the importance of flower fertility in the mating systems applied in seed orchards, and the research results on floral biology of fruit tree rootstocks propagated by seed (Prunus avium, Prunus mahaleb, Prunus armeniaca, Prunus cerasifera, Prunus insititia, Prunus amygdalus, P persica, P amygdalopersica, Pyrus pyraster, Pyrus communis and Pyrus betulifolia) over the last decades.

• Treatments for improving tree growth, yield and fruit quality and for reducing double fruit and deep suture incidence in “Desert red” peach trees

  7-19.

  M. A. Zayan

  G. B. Mikhael

  S. K. Okba

  Views:

  268

  Five years old “Desert red” peach trees budded on Nemaguard rootstock and grown in sandy soil at commercial orchard Al-Nubaria city, El-Behira Governorate-Egypt were treated with some agricultural treatments involving thinning out pruning, fruit thinning and foliar application of potassium silicate (25% S +10% K2O) at 0.1% and super grow (20% N, 20% P2O5 and 20% K2O) at 0.3% in 2014 and 2015 seasons, to study their effects on yield and fruit quality and the relationship between nutrient balance and yield of “Desert red” peach trees. Beside, testing the influence of used treatments on two physiological disorder, double fruit and deep suture %. Also, economic evaluation of different treatments was done. All obtained data were statistically analyzed using a randomized complete block design. Depending on the obtained results in this study, it could be concluded that application of thinning out pruning 35%, fruit thinning by leaving 15 cm between fruits on one-year old shoot at 20 days after full bloom and foliar application of potassium silicate which sprayed five times during each growing season at fruit set, the second fruit development stage, the beginning of the fruit color change and twice after month from harvest, most profitable treatment for peach trees grown under conditions of this investigation. This treatment gave the best vegetative growth, yield, fruit quality, higher crop value with high net income /fed. from “Desert red” peach trees, in addition, reduced the percentage of double fruit and deep suture by more than 50% in both seasons, therefore, the study recommends this treatment for “Desert red” peach growers.

• Influence of pesticide use on flower formation and fertility of some fruit species

  103-106

  I. J. Holb

  Views:

  210

  This review evaluated previous studies on the effect of pesticide use on flower formation and fertility of some fruit species. The study was divided into two parts. First part of the overview will evaluate the most commonly used fungicides on pollen toxicity and their germination ability under fungicide exposure on different fruit species. Effect of fungicides on fruit set was also critically reviewed. Second part of the study summarised those few studies which determined the effect of some insecticides and acaricides on flower formation and fertility.

• General principles in variety-association for intensive plantations of pomeceous fruits

  96-101.

  M. Soltész

  J. Nyéki

  Z. Szabó

  Views:

  160

  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.

• Honeybee (Apis mellifera L.) visitation at the flowers of quince cultivars (Cydonia oblonga Mill.)

  95-102.

  P. Benedek

  T. Szabó

  J. Nyéki

  Views:

  147

  Studies were made on the bee visitation of 6 quince cultivars and on the foraging behaviour of honeybees at quince flowers for 3 consecutive years. The bee visitation was highly intense because both the plantation and its surrounding was overpopulated by honeybee colonies. Some 5.5 bee visits were counted in average at 50 opening quince flowers in 10 minutes and some 9.7 flowers were visited of the 50 ones observed meanwhile. This equals some 7 bee visits per flower per day per in good weather. Bee visitation, however, was variable and it was greatly different in the three consecutive years with fairly favourable weather. Some cultivars tended to be more and others less visited by honeybees than the others but these differences were not consequent at each occasion. No consequent relationship between the weather and the bee visitation of quince trees could be recognised. It was concluded that .other factors were responsible for the variable nature of the bee activity at quince. Most honeybees tended to collect pollen (51.6% in average for the 3 years) and usually much less gathered for nectar only (19.9%), and the rest of them were mixed behaviour foragers gathering for both (28.5%). There were some slight differences in the foraging behaviour of honeybees at some cultivars but these differences were not always consequent in consecutive years. Also the nectar production of flowers failed to affect the bee visitation and the foraging behaviour of honeybees definitely. For the variable nature of bee visitation and bee behaviour at quince flowers, supplementary pollination is needed to achieve as high set of fruits as high is required to a good crop at quince (at least 20-25% because the flower density is low of this fruit tree species). Since the intensity of bee visitation at the flowers is the only reliable estimate of the necessity of supplementary bee pollination further research is needed to explore the relationship between the number of honeybee visits and the consequent fruit set at quince.

   

• Utilisation of data raised in blooming phenology of fruit trees for the choice of pollinisers of plum and apricot varieties

  35-41.

  Z. Szabó

  J. Nyéki

  M. Soltész

  Views:

  169

  Information concerning the blooming time of stone fruit varieties is, first of all, an important condition of finding suitable pollinisers securing adequate fruit set. For that purpose, varieties are assigned to blooming-time-groups. Depending on the number (3 or 5) of the groups, i.e. the length of intervals separating the groups established, pollenisers are to be chosen for self-incompatible and partially self-fertile varieties belonging to the same blooming-time-group. The mutually most overlapping blooming periods of the respective varieties should be found by raising data of their blooming phenology, i.e. dynamics, which is compared by drawing their phenograms and calculating blooming (V) indices. Variety combinations have to be checked, however, concerning mutual fertility relations of the respective pairs of varieties. That is most important in the case of Japanese plums because of the abundant incompatible combinations. Synchronous blooming has been determined by assigning the varieties to blooming-time-groups, or comparing overlaps of blooming phenograms, or by blooming (V) indices. Synchronous blooming phenology has been studied in European plum varieties (111 varietiy combinations) Japanese plums (156 variety combinations) and apricots (153 variety combinations) under Hungarian conditions, over several seasons. In determining overlaps, the less favourable season has been considered as decisive. Polliniser combinations have been chosen with at least 70% synchronous blooming. Blooming time of varieties is an important part of the variety descriptions. Blooming dates may serve also for the estimations of frost risk or security of yield.

• Fruit bearing shoot characteristics of apricot and sweet cherry cultivars in Hungary

  107-110.

  S. Thurzó

  G. Drén

  M. Dani

  B. Hlevnjak

  V. Hazic

  Z. Szabó

  J. Racskó

  I. J. Holb

  J. Nyéki

  Views:

  256

  : Our study was carried out on 23 apricot and 9 sweet cherry cultivars in February 2005. Fruiting laterals were classified into four groups (0-10 cm, 10-20 cm, 20-40 cm and >40 cm) and then the density and setting of flower buds were evaluated and expressed as bud/cm. The flower bud density of four types of fruit bearing shoots and the changes in the frost resistance were studied. Shoots were collected from a young orchard in Gone (apricot), Siófok (sweet cherry) and Nagykutas (sweet cherry). There were significant differences among the cultivars in the density of flower buds. The number of flower buds/cm shoot length ranged between 0.91 and 2.20 in the average of the different fruit bearing shoot types on apricot. Based on the results, the bud density of shorter shoots is generally higher on apricot, but this is not valid for all cultivars. For cvs. Magyarkajszi and Ceglédi bíborkajszi, the highest flower bud density was detected on shoots of medium length (10-40 cm). There were fivefold and almost twofold (1.85) differences in bud density among cultivars on shoots shorter than 10 cm length and longer than 40 cm length, respectively. The ratio of the bud densities of the different types of shoots also ranged between wide boundaries. For cvs. Bayoto, Toyesi and Toyiba this ratio was 2.5-3.5, while for cv. Magyarkajszi it was 1.3.

  In the average of fruit bearing shoots on sweet cherry, cv. Bigarreau Burlat (1.10 bud/cm) and cv. Germersdorfi 45 (0.61 bud/cm) had the largest and the lowest flower bud density, respectively. Among the fruit bearing shoots, the largest flower bud density was in the group of 0-10 cm fruiting laterals. Among cultivars, cv. Bigarreau Burlat had the largest bud density. In the groups of n- i 0 cm, 10-20 cm, 20-30 cm and 30-40 cm fruiting laterals, the lowest flower bud density was for cv. Linda, cv. Germersdorfi 45, cv. Ferrovia and cv. Sunburst, respectively. On cvs. Van and Bigarreau Burlat, large numbers of double-set flower buds were observed on the fruit bearing shoots longer than 20 cm. Fruit setting differed on the different types of fruit bearing shoots, with the lowest value measured on above 40 cm shoots. The highest fruit setting was observed on cv. Katalin, while the lowest value was measured on cv. Germersdorfi 3.

• Field evaluations of 14 sweet cherry cultivars as pollinators for cv. Regina (Prunus avium, L.)

  75-77.

  S. Thurzó

  M. Grandi

  L. Lagezza

  S. Lugli

  I. J. Holb

  T. Szentpéteri

  P. T. Nagy

  Z. Szabó

  M. Soltész

  J. Nyéki

  S. Sansavini

  Views:

  216

  In this study, the pollen of 14 sweet cherry cultivars (‘Anella’, ‘Duroni 3', 'Badacsony', 'Cristalina', 'Ferbolus', 'Ferrovia',

  'Georgia', 'Hudson', 'Kordia', 'Sam', 'Schneiders’, ‘Spate’, ‘Knorpelkirsche', 'Skeena', 'Summit', 'Sylvia') was used to fertilize the emasculated flowers of sweet cherry cv. 'Regina'. Fruit set was assessed three times during fruit development: 14 May, 30 May and 27 May 2007. We observed full incompatibility among the 14 cultivars for cv. 'Cristalina', which is in the same S-allele group as cv. 'Regina'. After analysis of our data, we have results about fertilization efficiency of the cultivars. Most of the evaluated cultivars are inadequate to fertilize cv. 'Regina' to a sufficient degree. There were two exceptions, cv. 'Sam' and cv. 'Skeena', where percentage of ripened fruits was above 20%. These two cultivars can guarantee such a pollination, which ensures ample quantity of ripened fruits. Results of this study have proved three other cultivars to be quite good pollinators for cv. 'Regina'. In conclusion, ideal pollinators for cv. 'Regina' could be — apart from above-mentioned two cultivars, 'Sam' and 'Skeena' — cvs. 'Sylvia' and 'Bianca', which was suggested by more literature sources.

• The effect of spring frosts on the nectar production and the bee visitation of fruit trees

  86-89.

  P. Benedek

  J. Nyéki

  I. Amtmann

  F. Bakcsa

  J. Iváncsics

  Z. Erdős

  I. Skola

  Views:

  151

  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.

   

• Phyl-Gold: a product to diminish russeting of 'Golden Delicious' apples

  131-133.

  L. Csiszár

  T. Bubán

  F. Takács

  M. Benedictyné Rátz

  L. Oláh

  Views:

  128

  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.

   

• Rootstock effects on fruit drop and quality of 'Arlet' apples

  69-75.

  J. Racskó

  J. Nagy

  J. Nyéki

  Z. Szabó

  L. Budai

  S. Zaheri

  M. Soltész

  Views:

  199

  The aim of this study is to investigate the effect of different growth inducing rootstocks on fruit drop of apple. This research was conducted for 3 years at Nagykutas, Western Hungary on apple cv. 'Arlet'. For the experiments, 3 different growth inducing rootstocks were choosen: M.9 (weak), MM.106 (moderate) and crabapple seedling (strong). There were 3 fruit shedding periods on the trees grafted M.9 and MM.106 rootstocks, but in the case of crabapple seedling, only 2 were found. The measure of fruit drop was closely related to seed count of fruits; seed number was the lowest, fruit drop was the highest. The lowest seed number was counted in fruits from trees on crabapple seedling. Seasonal changes of leaf:fruit ratio mainly depended on shoot growth and fruit drop. The rise of the curve of leaf:fruit ratio was very important during the first phase of fruit development, in especially at the end of June and in the beginning of July. The cause of this is that first and second periods of fruit drop appeared during this term. The rise of the curve was important in the beginning of June and the end of July on crabapple seedling. Decreasing tendency of quality parameters was found of fruits from trees on M.9, MM.106 and seedling rootstocks, except flesh firmness which was the highest in fruits from trees on crabapple seedling.

• Temporal changes of the frequency of spring frost damages in the main fruit growing regions in Western Hungary and in East Hungary

  81-87.

  L. Lakatos

  Cs. Fieszl

  Z. Sun

  J. Zhang

  Z. Szabó

  M. Soltész

  J. Nyéki

  Views:

  220

  Most of the risk in Hungarian fruit growing is the damage caused by late spring frosts. The frequency of late frosts seems to increase nowadays. The aim of the study was to check this contention: what is the real probability of the damages. Based on earlier experiences, the physiological LT50 function has been elaborated for new fruit varieties, which are eligible to moderate the danger when being threatened by frost. By means of this technique, the probability of freezing is distinguished between frost susceptible, frost resistant and medium frost resistant fruit species and varieties around their blooming time. The degree of frost damage depends on the duration and severity of the low temperature and not at least on the frost tolerance of the plant. For that purpose, the frequencies of frost damages were studied at two Transdanubian and two Trans-Tisza fruit growing sites by means of a meteorological database for the 60-year-long period 1951–2010. Being aware of the LT50 values changing during the phonological phases of the fruit trees from budding, bloom, fruit set and fruit growth, the number and date of critical (frosty) days could be settled. An important role is attributed to the orographic relief and the height above the sea level of the site, as 20–30 m differences and expositions may become decisive within the same plantation. The spatial distribution of damages is also dependent on the air circulations within the Carpathian basin. At the southern and northern borders of the country, especially valley bottoms represent additional risks of frost. Most spring frost damages are experienced in April 20–22, and cause heavy damages by temperature minima between – 3°C and – 6°C. The severity of damage depends largely on the temperature of the preceding few days. The earlier bloom the heavier damage is expected. The study is emphasising the importance of the varieties. Frost tolerance of some varieties may lower the risk of spring frosts by 40–50%, as experienced on the plantations. The quantifi cation of the risks based on data raised during the last years will be suitable to defi ne the security of yields of each growing site successfully.

• Effect of the placement of self-incompatible apricot varieties on their yield in commercial plantations

  82-86.

  J. Nyéki

  Z. Szabó

  Views:

  143

  Earlier studies concerning self-, free- and cross- fertilization of apricot varieties grown in Hungary, proved the existence of self-sterile as well as self-fertile varieties within the recommended assortment. The self-sterile and partially self-fertile varieties should be planted in association with polliniser varieties, only. The present paper reports about the yields of trees of the widely grown, self-sterile local variety, Ceglédi óriás (Giant of Cegléd), depending on the distance of adequate polliniser trees. In the univarietal, 27 row-wide block of the relevant variety, an efficient polliniser, Magyar kajszi was planted to the 10th and 19th row. In the close vicinity, another block of polliniser, Rózsakajszi C. 320 was located. The number of fruits set per tree has been counted or estimated in two consecutive years. In both seasons, the yield of the Ceglédi óriás trees diminished with the growing distance from the nearest polliniser trees. Those trees in the center of the block, between the two (10th and 19th) rows of Magyar kajszi bore acceptable yield (40 kg/tree in 1987), however, considerable reduction of the number of the fruits set was stated already in the 4-5th row from the polliniser away. Similar gradient of fruit set was apparent in relation to the neighbouring block of Rózsakajszi C 320. The beneficial effect of the vicinity of polliniser varieties was obvious as far as the distance of the 10th row. Taking into consideration the self-sterility, the early blooming time and the poor fertilization of the variety Ceglédi óriás, a planting design of associating it with at least two polliniser varieties (e.g. Gönci magyar kajszi and Ceglédi bíbor) is highly recommended. On the basis also of earlier results, a proposal has been developed for the association of apricot varieties as recommendations for optimising yields. Blooming time, fertilizing potential, schedule of the picking season and market possibilities have to be considered simultaneously.

• Bud-, flower- and fruit-density in stone fruits

  59-69.

  Z. Szabó

  J. Nyéki

  Views:

  182

  In 164 varieties of five stone fruit species, counts of flower buds, flowers and fruits set have been performed, regularly, between 1982 and 2002. The critical number and sample size has been determined for the purpose to estimate the yielding potential of peach plantations. For a rapid test, 10 shoots per variety are recommended. In sour cherry and peach varieties, the number and ratio of leaf and flower buds has been assessed on bearing shoots of different length.

  The typical flower bud density of 129 peach varieties varies, as a rule, between 0.13 and 1.10 bud/cm. Three groups of flower-bud-densities could be distinguished: low (0-0.40 bud/cm), intermediate (0.41-0.60 bud/cm), high (more than 0.60 bud/cm). About 62% of varieties belong to the intermediate group. Negative correlation has been found between flower density and relative fruit set, whereas positive correlation between flower density and fruit yield.

  The results are utilised in the description and choice of varieties, moreover, in choosing of optimal pruning policies. Varieties of high flower bud densities are recommended to be preferred for growing sites with frequent late frosts. Abundantly yielding varieties of low vegetative vigour are to be pruned more severely than those characterised by low yields, vigorous growth and low flower density. Sour cherry varieties, which are inclined to grow "whips" ought to be stimulated to grow longer shoots (40-50 cm per year), than varieties woid of that tendency (30-40 cm).

• Inheritance of blooming time in walnut, with regard to the property of reproductional autoregulation of species

  118-122.

  P. Szentiványi

  Views:

  129

  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.

   

• Fruit drop: I. Specific characteristics and varietal properties of fruit drop

  59-67.

  J. Racskó

  J. Nagy

  M. Soltész

  J. Nyéki

  Z. Szabó

  Views:

  370

  The basic conditions of fruit set (synchronic bloom, transfer of pollen, etc.) still do decide definitely the fate of the flower in spite of the best weather conditions. Beyond a set quantity of fruits, the tree is unable to bring up larger load. A system of autoregulation works in the background and causes the drop of a fraction of fruits in spite of the accomplished fertilisation and the equality of physiological precedents. This study discuss this physiological process based on the international specific literature. The further development of fruits maintained on the tree depends mainly on the growing conditions (e.g. water, supply of nutrients, weather adversities, pruning, fruit thinning, biotic damages, etc.), which may cause on their own turn fruit drop especially at the time of approaching maturity.

• Possibilities and limits of use plastic constructions in fruit growing technologies

  71-75.

  I. Gonda

  B. Vaszily

  M. Soltész

  Views:

  214

  On the Experimental Station Pallag of Debrecen University different combinations of fruit species and rootstocks have been raised under and without plastic foil cover in 2002. The growth and productivity of the grafts was our objective of comparison. Results revealed substantial differences in fruit set and yield depending on species and varieties. Sweet and sour cherry varieties grew much shorter under the plastic cover, whereas apricots, peaches and plums set fruit much more eagerly compared with the trees outside the plastic cover. Outside the plastic cover, the trees were much more developed at the beginning of their fruiting period. In spite of that, the growing processes were more intense under the foil. The differences are allegedly due to the repeated summer pruning necessary under the restricted space of the foil, on the other hand, due to the root concurrence because of the dense planting. Regarding the inner properties of the fruits, soluble solids, sugar and acids were higher outside, whereas macro- and mezzo-elements (P, K, Ca, Mg) were more abundant in fruits grown under the foil cover. Further efforts to explore those relations with other varieties and rootstocks are justified.

• Floral biology of hazelnut (Review article)

  7-19.

  M. Soltész

  J. Nyéki

  Views:

  212

  Floral biology of hazelnut (Review article)

• Fruit drop: The role of inner agents and environmental factors in the drop of flowers and fruits

  13-23.

  J. Racskó

  G. B. Leite

  J. L. Petri

  S. Zhongfu

  Y. Wang

  Z. Szabó

  M. Soltész

  J. Nyéki

  Views:

  400

  The basic conditions of fruit set (synchronic bloom, transfer of pollen, etc.) still do decide definitely the fate of the flower (Cano-Medrano & Darnell, 1998) in spite of the best weather conditions (Stösser, 2002). Beyond a set quantity of fruits, the tree is unable to bring up larger load. A system of autoregulation works in the background and causes the drop of a fraction of fruits in spite of the accomplished fertilisation and the equality of physiological precedents (Soltész, 1997). There are also basically genetic agents in action. The further development of fruits maintained on the tree depends mainly on the growing conditions (e.g. water, supply of nutrients, weather adversities, pruning, fruit thinning, biotic damages, etc.), which may cause on their own turn fruit drop especially at the time of approaching maturity.

• Inter-incompatibility of self- incompatible apricots and their varietal properties

  79-81.

  Z. Erdős

  Z. Szabó

  J. Nyéki

  Views:

  166

  There are four apricot varieties grown in Hungary derived from local selections known to bear fruits of giant (60 - 100 g) size: Ceglédi óriás, Nagykőrösi óriás, Szegedi mammut and Ligeti óriás. Being morphologically similar, they seem to be closely related to each other. The detailed study of the morphology (of leaves and fruits) and phenology (of blooming and ripening dates) as well as the fertility relations was aimed to find out the degree of kinship between the varieties in question.

  It was stated that the value of morphological traits is variable from the taxonomic point of view. The most important signs of common origin were the time of blooming and the leaf size. Less valuable are the date of m:iurity and the size of fruit because of their variability. In the literature Satin') & Nyeki (1991) published the first proof of inter-incompatible relation between apricot varieties. This should be considered as an argument of close genetic relation between those "giant" varieties of apricots.

  The first three varieties. Ceglédi óriás, Nagykőrösi óriás and Szegedi mammut are closer related in blooming and ripening date, as well as in size of fruit to each other than the variety Ligeti óriás.

   

• Morphological and phenological properties of sour cherry varieties grown in Hungary and their inter-incompatibility relations

  114-117.

  J. Nyéki

  Z. Szabó

  T. Szabó

  M. Soltész

  Views:

  151

  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 critical evaluation of methods used for S-genotyping: from trees to DNA level

  19-29.

  J. Halász

  A. Hegedűs

  Views:

  176

  Fruit setting behaviour of fruit trees remains to be in the focus of plant breeders and growers. Realizing that most species (cherry, apple, pear etc.) are self-incompatible and certain cultivars are cross-incompatible, mutual fertility properties and their reliable determination are of great interest. This review gives a comprehensive description of all known S-genotyping procedures, i.e. the classical fruit set analysis after open field test crosses; pollen tube growth monitoring with fluorescent microscopy; stylar ribonuclease electrophoresis (using different types of isoelectric focusing and 2-dimension polyacrilamide gel electrophoresis); as well as the most recent polymerase chain reaction based DNA-level analyses and DNA sequencing. The review presented not only gives a compilation of the bases of the methods described but also provides a critical evaluation and a comparative characterization of their applicability.