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Influence of time of planting on yam performance and pest infestation in humid rainforest of southwestern Nigeria
77-84.Views:29Yams (Dioscorea spp.) are annual or perennial tuber-bearing and climbing plants that belong to the family Dioscoreaceae. Only six principal species are grown for human consumption, while several others are produced for medicinal purposes. This study was designed to determine the influence of time of planting on yam performance and pest infestation in humid rainforest of southwestern Nigeria. The experiment was conducted in Randomized Complete Block Design (RCBD) with three treatments replicated five times. The planting materials are dipped into wood ash and allowed to dry up. The number of yam setts required for this work is 4 pieces, each of white yam sett, seed yam, and 4 pieces of water yam setts for the different planting times. The planting is done in five (5) phases. In each phase 12 heaps are planted, 4 white yams (seed yam), 4 yam setts (white yam) and 4 water yam setts. No significant difference was observed in 50% sprouting both in treatments and replication. There is significant difference in yield both in treatment and block. Yam planted in April (R5) has the highest yield with 3.7 kg, followed by those planted in ending March (R4) with 2.83 kg, followed by those planted in mid-February (R1) with 1.43 kg, then those planted in February ending (R2) with 1.2 kg and those planted in mid-March (R3) with 1.17 kg respectively. The highest level of destruction was witnessed in white seed yam planted in Mid-March and Mid-April as well as white yam sett planted in Mid-February. The lowest level of destruction was found in water yam sett planted in February ending. Shifting planting date can reduce larval survival and pest populations in yam tuber.
Keywords: Dioscorea spp., pest infestation, destruction, sprouting, yam performance.
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General defense system in the plant kingdom III.
45-54.Views:329Our observations regarding the symptoms not fitting into, significantly differing from the hypersensitive defense system, which we noticed during the judgment of several plant species, symptoms provoked on several million plants have constituted a unified entity. They have provided evidence for the existence of a different plant defense system. We called this so far unknown basic response of plants to biotic effects as general defense system. This system defends them from the attack of numerous microbe species in the environment.
The evolutionary intermediate phase between the general and the specific, the two defense systems is the susceptible host—pathogen relation. The vertical resistance system of plants escaping from the susceptible host—pathogen relation, based on specific hypersensitive reaction also suggested the existence of a more original, general defense system and the susceptible host—pathogen relation developed as a result of the collapse of that system.
The evolutionary relation of the two defense systems is proved by the only recessive inheritance of the older general defense system and in the majority of cases dominant hereditary course of the specific defense system. In our experiences, the modifying genes of the recessive general defense system, in most cases, are behind the specific defense systems, which are known to have monogenic dominant hereditary course and react with hypersensitive tissue destruction. This seemingly striking genetic fact is explained by the following: the general defense system less dependent on environmental effects regulates much faster pathophysiological reaction than the specific resistance genes strongly dependant on environmental effects coding dominant hypersensitive reaction.
The general and specific defense reactions, the processes excluding the microbes attacking plants with compacting of cell growth and tissue destruction, which mean two opposite strategies, building on and regulating each other constitute the entity of resistance to plant disease.
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General defense system in the plant kingdom
79-84.Views:286The 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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Stress physiology of palm trees II. The effect of heavy metals and high irradiance on the photosynthesis of palm Trachycarpus fortunei
84-88.Views:312A study was carried out to analyse the individual and combined effects of heavy metal toxicity and high irradiance on the photosynthetic characteristics of young, fully expanded leaves of palm seedling Trachycarpus fortunei under laboratory conditions. Heavy metals were found to inhibit both the light and dark reactions of photosynthesis and the inhibition was more affected in the light than in the dark. Single photoinhibitory conditions caused a 60 % decrease in the electron transport activity after 120 min of light exposure which was completely reversible in the dark. In contrast, the combined effect of high light and heavy metal treatment resulted in a 90 % decrease in the activity, but no reversible recovery in the dark could be detected. This indicated that the simultaneous effect of these two stress factors led to irreversible damages of the photosynthetic machinery and as a consequence caused the general destruction of the plant.
Abbreviations and symbols: Fo: initial chlorophyll fluorescence; Fm: maximum total fluorescence; Fv: variable fluorescence; AFi: intermediate level of fluorescence induction; PSII: photosystem 2.
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Book review
37-39.Views:407Plum is a significant temperate fruit and a very important fruit species in Hungary as well. Cultivation has moved beyond the area boundaries of the Northern Hemisphere many centuries ago. Domestic (European) plum production has been particularly affected by the pandemic-scale destruction of the Sharka virus and worldwide breed changes. According to FAOSTAT (2016) data, world plum production is 12 million tones, with 36% from Eurasian, 63% from Japan and other Asian varieties. The share of American plums is only 1%. Domestication and dissemination of plums is „multi-stepped” because homemade (taste) plums are hybrids of two nature species in the first place, but Japanese plums (hybrids with Chinese plums or Prunus cerasifera) are not uniform; the role of the American plum species is much smaller, though their prospects cannot to predict with certainly. The book consists of 19 chapters, finding a complex way of summing up linguistic, historical, floristic, historical-botanical, cultivation, and morphological and anatomical knowledge.
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Selection of the chance seedlings of `Mézes körte' (Pyrus communis L.) from the gene bank of Keszthely
21-27.Views:811We have concluded the selection tests of the `Mézes körte' seedlings planted in the spring of 2006, with special emphasis on the cotyledonary, foliage leaf and the height of plant. Out of the 75 seeds planted in rows, there were 40-45 pieces growing out, so during the first cotyledonary test we had to calculate with almost 40% decay. On 12th April 2006, we recorded some of the important characteristics of the seedlings in their cotyledonary stage which characteristics were important from the point of view of selection (cotyledonary form, cotyledonary length, cotyledonary thickness, cotyledonary colour, cotyledonary petiole length, cotyledonary petiole thickness, cotyledonary petiole colour). The above morphological characteristics are shown in Table No. 1-6. We have also tested the seedling in foliage leaf state, paying special attention on the development stage of the plants (colour of foliage leaf , height of plant). We have completed statistical calculations of the two above mentioned characteristics. The result of that is summarised in Table No. 8-9. The variation coefficient show smaller value in the case of the foliage leaf number (15-32%), while the wider range of spread of the data referring to the height of the plant is shown by the 33-61% CV values. On charts No 4-9. we present the relationship between the height of the plant and the number of foliage leaf, as well as the differences between the two graphs. Based on the above charts and graphs it can be defined that the 40% destruction of the developing seedlings during the period till the next measurement reached 70-80% level. In spite of this however some seedlings showed strong and balanced growth (A44, B42, C25, D16, E5, E39, F38), the further testing and selection of those is to be completed in the future.
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Detection of natural infection of Quercus spp. by the chestnut blight fungus (Cryphonectria parasitica) in Hungary
54-56.Views:514The chestnut blight fungus Cryphonectria parasitica (Murrill) Barr [syn.: Endothia parasitica (Murr) Anderson] caused almost total destruction of the American chestnut (Castanea dentata) and widely spread on European chestnut (Castanea saliva) in many European countries. In Hungary, because this fungus threatens most of the Hungarian chestnut stands, great efforts have been made to delay its spread. Biological control with Hungarian hypovirulent strains of the pathogen seems to be an effective method for saving the affected chestnut trees. Until 1998 the fungus was detected on Castanea saliva only, then on some trees of young Quercus petrea in mixed chestnut forests, which also showed the typical symptoms of blight (Kőszeg and Zengővárkony). Although blight symptoms are not so serious in Quercus spp. than in Castanea spp., it seems that C. parasitica threatens the young Quercus spp. in Hungary, mainly in heavily infected chestnut forests. This is the first report of C. parasitica cankers on oak in Hungary.
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General defense system in the plant kingdom II.
69-71.Views:262In addition to successes achieved in certain varieties in resistance breeding based on a defense reaction of host plants involving hypersensitive tissue destruction, resistant varieties putting a very strong selection pressure on pathogens have selected more and more aggressive types of pathogens. The never-ending race between plant and pathogen resulting from this can only be controlled by a defense system characterised by a different strategy. In each of the plant species that we bred a defence system was found, which contrary to hypersensitive reaction strives to keep the tissues at all costs and is not pathogen specific. This is implied in the term general defense system.
