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General defense system in the plant kingdom
79-84.Views:300The goal of plant breeders is to improve the resistance of crops against virus, bacterium and fungus pathogens was easiest to achieve by selection for phenotypes displaying the hypersensitive reaction. The resistant plant of that type keeps its health by preventing or delaying the systemization of the pathogen by destruction of cells and tissues of variable size or amputation of the contaminated organs. The faster the reaction of the host plant is the more efficient and economical is the defense, since the extent of tissue destruction decreases proportionally with the speed of reaction.
During a breeding program for resistance carried out on several plant species, mainly vegetables over thirty years, also an alternative defense reaction has been experienced, which fundamentally differs from the hypersensitive reaction. In that reaction the cells and tissues of the host plant being exposed to the pathogen do not die, on the contrary they hinder systemization of the pathogen by tissue thickening. An additional significant difference is that on the contrary to hypersensitive reaction this reaction is less host- or pathogen-specific and works excellently even at high temperature (over 40 °C).
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Farm-scale evaluation of two widely used sanitation practices for reducing primary inoculums of apple scab in organic apple production
15-18.Views:696Effects of two widely used sanitation practices were evaluated at farm-scale level on leaf degradation and primary infection by Venturia inaequalis in an organic apple orchard (Eperjeske) on two apple cultivars (Jonathan and Prima) from 2011 to 2013. The tested sanitation practices were eradication of fallen leaves by collection and disc cultivation. Treatments of eradication of fallen leaves by collection and disc cultivation reduced signifi cantly (P< 0.001) leaf litter density with 70–85 and 40–55%, respectively, compared to untreated plots in both years. Above treatments in the same order reduced spring scab incidence with 40–50, and 10–20%, respectively, compared to untreated plots. Incidence of leaf scab in autumn was not signifi cantly lower (P< 0.05) in the treatments in the years.
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Reactions of different plant organs of pear cultivars to Erwinia amylovora infection
17-21.Views:366Research project has been initiated in 1999 with the aim of evaluating the degree of susceptibility/resistance of pear cultivars grown in Hungary to fire blight disease caused by Erwinia amylovora. The recently selected promising cultivars were also examined. Inoculation experiments were conducted in controlled greenhouse conditions because of quarantine regulations in Hungary. Following the disease process, development of symptoms of plant organs (shoots, flower parts, fruits) was observed. Suspension of two E. amylovora strains (Ea 21, Ea 23) isolated from pear was used in a mixture (5x108 cells x m1-1) for the inoculation. Twenty-six pear cultivars were examined and grouped into four categories: low susceptibility, moderately susceptible, susceptible and very susceptible. Most of the cultivars were susceptible or very susceptible while some promising 'Eldorado', 'Harrow Delight' and `Hosui' showed low susceptibility.
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Cost-effective plantlet production and wintering method of virginia fanpetals (Sida hermaphrodita L. Rusby)
137-141.Views:481The main goal of this research was to work out programmable, cost-effective and industrial scale technologies of mass propagation from the seeds of rootstock nurseries of undomesticated American populations of Sidahermaphrodita. During our previou`s seed treatment experiments, it was concluded that around 60% of the Virginia fanpetalsseeds collected during the four cropyears can be considered as high quality, infection-free, normally imbibing and germinating seeds (Kurucz et al., 2013a,b). The experiments performed with the nurse-in-tray method developed by us showed that the summer-autumn nurse-in-tray plantlet production and unprotected wintering of Virginia fanpetals with properly pre-treated and fractioned seeds is a promising new method. No weeds appear between the plants, but only on the side of the cases during plantlet production. The investment cost of the method is minimal. There are no heating costs and this phytotechnique can be easily and properly mechanised. Plantlet production can be performed near the large-scale plots. After exploring the root and shoot system, it was concluded that the nurse-in-tray method is suitable for producing plantlets with hardened and strong roots. Scheduled plantlets can be produced in an industrial scale volume by the time of early spring (March) plantlet planting. The excavateof plantlets can be flexibly adjusted to the needs; they may even grow in the plantlet cases for a whole year. We think that these innovative plantlet production and wintering methods which are suitable for large-scale use will make Virginia fanpetals a proper feedstock for the constant supply of the Biomass Supply Chain both in Hungary and in European countries which are in the same climate zone. The comparative analysis of the costs of this procedure calls for further research.
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The comparison of several soil cultivation methods in the Tokaj-wine region
35-37.Views:391Our 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 observed 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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Detection and identification of phytoplasmas in peach based on woody indexing and molecular methods
35-41.Views:302Symptoms resembling phytoplasma disease have been observed on peach trees in a seed-source plantation of stone fruits in south Hungary quite recently. In this publication we report on the results of woody indexing of symptomatic peach trees on GF 305 indicator in the field and under greenhouse conditions as well as on molecular studies. Phytoplasma infection detected on GF 305 indicators in greenhouse and field indexing was confirmed by PCR. Nested PCR was conducted using universal primer pairs followed by group and subgroup specific primers for the second amplification. RFLP analysis of nested PCR products was performed using Rsal restriction enzyme. Based on the results of molecular studies it can be concluded that phytoplasmas, belonging to the European stone fruit yellows subgroup (16SrX-B) were identified in peach trees. Further studies on symptomatic peach trees originating from different parts of Hungary are in progress.
