Vol 14, No 3 (2008)

Published May 19, 2008



Test of the utility of apple retrotransposon insertion patterns for molecular identification of 'Jonathan' somatic mutants

Up until today, apple sport mutants proved to be indistinguishable from each other and their progenitors at the molecular level using random amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) marker techniques. This is not surprising, since the genomes of these somatic mutants differ... only in one or a few small regions that affect economically important characteristics, such as improved fruit colour, size, or flavour. In most cases, these genome differences are probably caused by retrotransposons which are able to convert their RNA transcripts to DNA with reverse transcriptase enzyme prior to reinsertion, but unable to leave the genome and infect other cells. Retrotransposon insertions can alter the expression of other genes and/or the structure of encoded proteins. The sequence-specific amplified polymorphism (S-SAP) technique is capable of revealing the genetic distribution of retrotransposable elements over the whole genome. The present study used this approach to try to characterize and distinguish 'Jonathan' somatic mutants via fingerprinting, which is an unsolved problem.

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Metaxenia in apples cv. 'Rewena', 'Relinda', 'Baujade' as influenced by scab resistant pollinizers

Fruit quality of cross pollinated apples (Malus x domestica) influenced by the metaxenic pollen effect of the pollinizer was observed in Hungary. Flowers of three resistant cultivars (`Baujade', `Rewena') were hand pollinated with other resistant apple cultivars. Fruits were harvested on 25 September, 2005. Fruit quality was investigat...ed in the laboratory of the Department of Pomology; Corvinus University of Budapest. Not only size and morphological parameters (diameter, height, stem length), but also refraction and acidic content of the fruits were measured.

According to the statistical analysis significant differences were determined on fruits among the groups as an effect of the pollen provider. In consideration of size parameters (diameter, height, weight) of `Rewena' fruits pollination partner 'Freedom' and 'Prima' caused outstanding results but `Florina' caused flatter fruits. Pollen of `Florina' and `Freedor-,' caused a higher percent refraction in the fruits of `Rewena'. In the case of `Baujade' fruits `Reglindis' — among cultivars we used as pollinizer — caused the biggest fruits medium flesh firmness and harmonic inner content values. `Rajka' caused on one hand smaller fruits and on the other hand higher flesh firmness and inner content values in the case of `Relinda' fruits. According to our data measured pollinizers varied the stem length as well.

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Brown rot blossom blight of pome and stone fruits: symptom, disease cycle, host resistance, and biological control

In this paper, important features of symptoms, biology and biological disease management are summarised for brown rot blossom blight fungi of pome and stone fruit crops (Monilinia laxa, Monilinia fructicola and Monilinia mali). Firstly, European brown rot caused by Monilinia laxa is discussed highlighting the blossom ...epidemiology features, then host susceptibility of the most important stone fruit species including several Hungarian and international cultivars. At the end of this chapter, recent biological control possibilities against Monilinia laxa are also included. Secondly, American brown rot caused by Monilinia fructicola is discussed. Symptoms, biological features of blossom blight and host susceptibility of flowers to Monilinia fructicola are demonstrated. Finally, the symptoms and the biology of the least frequent species, Monilinia mali are shown.

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Role of organosilicone surfactant in apple scab control under scab conducive weather conditions

Fungicides of integrated fruit production (dithianon, captan, and diclofluanid) and an organosilicone surfactant were compared in spray schedules from green tip until summer in order to control apple scab caused by Venturia inaequalis and to evaluate their phytotoxicity on fruit. Sixteen sprays of 1.8 kg ha-1captan, 0.41 ha<...sup>-1 dithianon, and 1.8 kg ha-1 diclolfluanid significantly (P=0.05) reduced the incidence of leaf or fruit scab compared to unsprayed products. All fungicides applied with organosilicone at 0.1% resulted in lower incidence of scab on young and older leaves as well as on harvested fruit, but these were not statistically always better than fungicides applied alone. In case of diclofluanid, the fungicide applied with organosilicone at 0.1% resulted in significantly lower (P = 0.001) incidence of scab on young and older leaves. Diclofluanid applied with organosilicone at 0.1% gave the best scab control on leaf and fruit. Treatments applied with fungicides alone had no significant effect on plant phytotoxicity compared to untreated control. All fungicides applied with organosilicone at 0.1% increased (P = 0.05) fruit damage compared to untreated control or fungicide applied alone, though these were not always significantly different. In case of percentage of fruit russet, treatment of dithianon 0.4 1/ha + 0.1% organosilicone significantly increased fruit russet, while fruit russet index significantly increased in the treatment of diclofluanid 1.8 kg/ha + 0.1% organosilicone compared to untreated control. In sum, application of surfactants can help to increase efficacy of scab fungicides; and consequently, to reduce the risk of fungus infection under high scab disease pressure. This fact may also be helpful in fungicide resistance management and reduced-spray programs with accurate scab warning systems.

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Impact of boron foliar fertilization on annual fluctuation of B in sweet cherry leaves and fruit quality

The goal of the study was to examine response of sweet cherries (Prunus avium L.) to boron (B) fertilization. The experiment was conducted during 2005-2007 in West Hungary on mature cv. `Germersdorfi 3' grafted on Prunus mahaleb rootstock.

Sweet cherry trees planted on a calcareous chernozem soil. Tree...s were foliar-fertilized with B. Foliar B sprays were performed: (1) in the spring, at the stage of white bud, beginning of flowering (B1), and (2) repeated 5 weeks after full bloom (B2). In each of spring spray treatments, B was applied at a rate of 0.15 kg ha-I. Trees untreated with B served as a control.

The results showed that B fertilization had effect on B concentration in leaf tissues, mostly after ripening. B was present significantly higher amount in leaf in treated samples after ripening.

Mean fruit weight was slightly increased by B fertilization. Fruit sensitivity to cracking was not influenced by B fertilization. Nevertheless, from our data it can be conclude that the sensitivity of fruit to cracking is improved when the fruit is riper, the fruit density and fruit weight are higher. The soluble solids varied between 15.0 and 15.9% according to the treatments. Our results for the monosaccharides investigated varied between 5.1 and 7.2 as glucose and fructose as well. Galactose and sucrose was detected very small amount in the unprocessed cherries. Applied B treatments increased sugar contents but decreased organic acid contents in sweet cherry fruits.

It is concluded that under conditions of this experiment, B fertilization can be recommended in sweet cherry culture to improve fruit quality and their appearance.

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Abnormalities of the stigma of sour cherry cultivar

The objective of this study was to evaluate the ratio of blackness of the surface of stigma of sour cherry cultivars. At the full bloom time of sour cherry 100 new opened flowers were marked in the internal (Inside), external (outside), bottom and upper parts of the crown of each cultivars including sour cherry cultivars ‘Érdi bőtermő', `D...ebreceni bőtermő', `Kántorjánosi', 'R. clone', 'Petri', Pándy', and 'D. clone'. The trees were replicated four times. The numbers of flowers with black stigma were counted and the percentage of dead stigma was calculated. In addition, tissues of black stigmata were investigated for blossom pathogens by microscopy. After flowering time the fruit set of the marked flowers counted and then percentage fruit set was calculated. Numbers of counted flowers were between 300 and 980 depending on the four position of the tree. Black color of stigma could be seen only on three cultivars (`Debreceni bőtermő', Érdi bőtermő' and 'Petri') out of seven assessed cultivars. The highest numbers of black colored stigma were found on cultivar ‘Érdi bőtermő' which ranged between incidences of 12 and 21%. Black stigma was never able to produce a fruit set. Microscopic examination revealed no pathogens associated with black stigma. Different part of the tree resulted different amount of black stigma. Black stigma was the largest on the outer part of the tree on cv. 'Érdi bőtermő' but also bottom part of the tree also produced larger number of black stigma on cvs. `Debreceni bőtermő' and ‘Érdi bőtermő'. Though symptoms were not typical to frost damage, we believe that black stigma is probably due to environmental factors during flowering. This might be associated with late spring cold coming from the soil surface as the bottom and outer part of the tree was more suffered from the disease.

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The comparison of several soil cultivation methods in the Tokaj-wine region

Our results show that the different cultivation methods have higher effect on the yield than on the grape quality. In 2007 the weather was extreme dry (from May to August only 195 mm precipitation was recorded) the straw mulch proved to be the best solution regarding the yield and the grape quality. Although no significant differences were obse...rved in the sugar- and titratable acidity content of the must, the ratio of noble rotted berries was higher on the straw mulched plots. Straw mulch could conserve the moisture content of the soil and it seems to be contributed to the conformation of suitable microclimate for Botrytis infection, but for long distance conclusions further examinations need to be investigated. The less yield and ratio of rot was observed in case of barely covered vines and the vegetative growth of the grape was less intensive in case of these vines.

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Role of hydrogen peroxide and Pharmaplant-turbo against cucumber powdery mildew fungus under organic and inorganic production

Cucumber leaves have been sprayed with a solution of hydrogen peroxide (H202) or Pharmaplant-turbo combined with organic or inorganic fertilizers under plasic house. Under the influence of H202, leaves exhibited resistant against Podoshaera fusca fungus, the causal agent of cucumber powdery m...ildew. H202 (15 mM) was able to decrease the disease severity from 90.4% to 12% in two experiments conducted in two seasons. Pharmaplant-turbo (Turbo) is new chemical compound and used as an antifungal compound. Turbo in 1 ml/L was able to decrease the disease severity from 90.4% to 11.5% in the both experiments as well. Both of H202 and Turbo were combined with organic treatment (compost + compost tea + seaweed extracts) which showed significant effect against cucumber powdery mildew fungus and strongly suppressed it as compared to control leaves. Organic treatment produced higher vegetative growth characters and greater early and total yields as compared to inorganic treatment, also organic fruits produced the lower nitrate content and the higher ascorbic acid content as compared to inorganic fruits. Our study have indicated that, H202 and Turbo combined with organic fertilizers play a role in the resistance of cucumber against powdery mildew by decreasing the disease severity. We suggest to give more attention to the direct application of H202 in low concentration and Turbo against powdery mildew diseases and other plant diseases.

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Using compost of grape manufacture and farm wastes as growing media in vegetable ad ornamental nurseries

This work was conducted at private nursery in Kafr El-Sheikh governorate during 2006 and 2007 seasons to investigate the possibility of using grape manufacture waste compost (GMWC) and farm wastes compost (FWC) in ornamental and vegetable nurseries as partially or totally replacement of coconut peat (CP) and vermiculite (V) in the growing mediu...m and also to find out the optimum media of tomato (Lycopersicon esculentum, cv. Castle Rock) and Cockscomb (Celosia plumosa) as comparing to a mixture of CP and V (1:1 v/v). The authors used a ten mixtures as followed: 1- Control (CP+V at 1:1 v/v), 2-GMWC (100 %), 3- GMWC +CP (1:1 v/v), 4- GMWC + V(1:1 v/v),5- GMWC +CP + V (1:1:1 v/v/v), 6- FWC (100 %),7- FWC+ CP (1:1 v/v), 8- FWC+ V (1:1 v/v), 9- FWC+ CP+ V (1:1:1 v/v/v), 10- GMWC+FWC+CP+V (1:1:1:1 v/v/v/v). Data recorded as seedling height, No. of leaves, total pigments, shoot fresh and dry weights, root length and root fresh and dry weights in order to assess the quality of both transplants of tomato and cockscomb. Both seedlings grown in medium contain a mixture of GMWC+CP+V displayed quality traits similar or better as to those of recorded from the control treatment.

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Reproductive biology of Duranta repens L. (Verbenaceae) in relation to its environment

Impact of environmental changes (temperature and RH) on reproductive biology in Duranta repens (Verbenaceae) growing at ten different sites of Agra was studied. It flowers throughout the year, with optimum flowering in September. The flowers are arranged in loose clusters on terminal or axillary racemes. They are either blue or lavende...r in colour, hermaphrodite, actinomorphic and complete. The plants exhibit floral polymorphism (increase and decrease in number of petals and stamens) and considerable variation in extent of pollen fertility, floral density, insect pollinators and fruit-set percentage. The changes in temperature and relative humidity during the entire flowering period, was found associated with the variation in floral structure, pollen fertility and fruit-set percentage. Based on the percentage of fruit-set during different seasons of a year, there were three distinct periods, namely maximum, moderate and minimum periods. The present paper deals with the comparative view of reproductive biology of this ornamental plant in these periods. During the months of August—November when temperature ranges between 13.7-36.6 °C and RH between 79-89% the plant exhibits maximum fruit-set percentage (68-85%). This was associated with maximum flowering, increase in floral size, and increase in visitation rates of pollinators and higher degree of pollen fertility. On the other hand, with temperature reaching to the maximum (15.1-41.5 °C) and reduction in RH (14.1-41.3%), the percentage of fruit-set was reduced to the minimum (21-30%). During this period, number of flowers/plant, floral size, pollen fertility, visitation rates of pollinators were reduced to the minimum. During this period floral polymorphism was also 'recorded.

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Bioactive phenols in leaves of Forsythia species

Nowadays a number of lignans (arctigenin, matairesinol, pinoresinol and phillygenin) have come to the fore in research due to their various biological activities. In this paper the accumulation of these constituents in leaf extracts of Forsythia plants (F. intermedia, F. ovata 'Robusta’ and `Tetragold', F. suspensa, F. v...iridissima) was quantified using a new isolation method, supercritical CO2 fluid extraction. The total phenolic and flavonoid contents, the antioxidant capacity and the aglycone lignan profile were determined in leaf extracts of Forsythia species. Within the phenols, the flavonoids were only present in small quantities, but the amount of aglycone lignans was extremely high. F. ovata `Robusta' had the highest total lignan content (103.8 mg/g) of all the Forsythia species. The main lignan in this species is arctigenin, which normally makes up about 60% of the total lignan content, but in the case of F. ovata `Robusta' this value was 96.1%. Since this arctigenin content is outstanding compared to that of other Forsythia species, it could be promising to develop a fermentation technology for the production of this natural compound.

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Ultrastructural and biochemical aspects of normal and hyperhydric eucalypt

Hyperhydricity was observed throughout in vitro multiplication phase of a Eucalyptus grandis clone. Ultrastructural approach of tissue and cell differentiation, izoenzyme patterns, binding protein (BiP) expression, and pigment content were performed. Hyperhydric tissues showed a reduction in cell wall deposition, reduction of ...membranous organelles, higher cell vacuolation, and more intercellular spaces than its normal counterpart. Additionally, several vesicles were present in hyperhydric cells suggesting the occurrence of organelle autophagy by autophagic vacuole. Lower pigment content, intercellular spaces on the epidermis and the induction of a molecular chaperone (BiP) were observed in hyperhydric phenotype. Evidences of schizolysigenous process of intercellular space formation are compatible with a stress condition. Although plastoglobulli were observed in normal and hyperhydric chloroplasts, they were more evident in the normal ones. Abnormal stomata also reflected a disruptive situation and morphogenesis disturbances which would difficult plant acclimatization. Further observation of the epidermis ultrastructure allows us to conclude that the presence of intercellular spaces on its surface may be constraining the recovery and development of hyperhydric plants. Similarly to BiP, other proteins such as esterase (EST), acid phosphatase (ACP), malate dehydrogenase (MDH) and peroxidase (PDX) are possible to be used as stress markers in in vitro conditions. Our results confirm earlier findings about negative effects of hyperhydricity on in vitro plant morphogenesis and ultrastructure, which in eucalypt is associated with a stressful condition contributing to lower propagation ratios.

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