Fruit Tree Nurseries Research Articles

New means of mechanization for fruit-tree nurseries in mountain and foothill areas of the North Caucasus

The article describes the present state of mechanization of horticulture and fruit-tree nursery, analyses the mechanization of technological process of parent bushes hilling. Production of planting material for establishing new type orchards depends on the degree of mechanization of technological processes in fruit-tree nurseries, more specifically on the availability of special equipment for work in mountain and foothill areas on stony and heavy soils. At this stage, the urgent task is to increase the efficiency of work of fruit-tree nurseries with simultaneous reduction of labour and power intensity by means of mechanization of production processes based on new technologies and technical tools for cultivation of planting material. The new type orchards, as a rule, are short-growing, high-yielding and require a 5-6 times bigger planting stock compared to old type orchards. Therefore, it is necessary to intensify the production of transplants in fruit-tree nurseries of a new type, and to lay for it the industrial foundation with the use of mechanization means for the care of parent bushes. This intensification is only possible on the basis of application of modern industrial technologies of reproduction of planting material taking into account the landscapes of the Republic of North Ossetia - Alania and the use of high-performance agricultural machinery, tractors and other equipment. The article proposes a technology and a combined unit for parent bushes hilling and row spacing cultivation, as well as a tent for budding of planting stock of fruit and berry crops when establishing the new orchards up to world standards. These devices allow to increase labour productivity under production of planting stock in conditions of mountain and foothill areas.

First report of stubby root nematode, Paratrichodorus teres (Nematoda: Trichodoridae) from Iran

During a survey of plant-parasitic nematodes in fruit tree nurseries in Iran, a species of the genus Paratrichodorus from the family Trichodoridae was found in the rhizosphere of apricot seedlings in Shahrood, central Iran, then subsequently in Karaj orchards. Morphological and morphometric characters of the specimens were in agreement with P. teres. The D2/D3 expansion fragment of the large subunit (LSU) of rRNA gene of the nematode was also sequenced. P. teres is considered an economically important species in agricultural crop, worldwide. This is the first report of the occurrence of P. teres in Iran.

Castanha tipo portuguesa no Brasil

Frutífera originária do Hemisfério Norte, a castanheira pertence à família das Fagaceae. O gênero Castanea apresenta sete espécies, das quais se destacam C. sativa Miller, C. crenata Siebold & Zucc., C. molissima Blume e C. dentata (Marsh.) Borkh. Tais espécies receberam denominações de acordo com o local de origem e säo conhecidas, respectivamente, por castanha-portuguesa (Portugal), castanhajaponesa (Japäo e Coreia do Sul), castanha-chinesa (China) e castanha-americana (América do Norte). Dada sua relevância como uma das mais importantes espécies frutícolas da antiguidade, as castanhas mantêm a tradição de consumo nas festas natalinas e, por conta de suas qualidades nutritivas e por ser um produto versátil, servem o ano todo, em alguns países, como alimento para pessoas e animais. O Núcleo de Produção de Mudas de Säo Bento do Sapucaí mantém uma coleção com algumas cultivares e seleção e, em parceria com a Universidade Federal de Lavras (UFLA), vem estudando essa fruteira, que possui grande potencial para a fruticultura brasileira.

Soil insect pests of cold temperate zones of East Asia, including DPR Korea: A review

Food crops have come under increasing threat from soil insect pests as a result of monotonous use of arable land and the unavailability or ban of soil insecticides. The development of new management strategies is hindered by the limited knowledge of the identity and biology of local soil pests. A literature survey was carried out focusing on the cold temperate zones of East Asia (north-eastern China, far south-eastern Russia, both Koreas). As for DPR Korea, field surveys were added. At least 53 soil insect species appeared to have wide-ranging importance. The highest diversity of soil pests attack maize (at least 29 species), cereals (27), soybean (19), potato (19), other beans (16), peanut (16), fruit tree nurseries (14), followed by cabbage, sorghum, cotton, grassland habitats, and sweet potato. Most belong to the Melolonthidae (21 %), Scarabeidae (15 %), Noctuidae (13 %) or Elateridae (11 %). Genera containing the most species were the melolonthid Holotrichia (at least five species), scarabeid Anomala (5), agromyzid Delia (4) and noctuid Agrotis, melolonthid Maladera, and gryllotalpid Gryllotalpa (each three). Below-ground damaging pests appeared widely problematic across the cold temperate zones, probably due to the limited variety of crops suitable for rotation or strip cropping, and efficient adaptation of pests to the soil environment as a result of long overwintering periods. This review will, as a result of making some of a vast repository of non-English language information available, help to better understand the soil pest community in these regions, and support the development of more effective control methods.

Main Pathogens Affecting the State of Health of Fruit Tree Nurseries in Transylvania Region

Transylvania Region, due to its climatic conditions represents a propitious region for fruit trees nurseries that produce fruit planting material. Prospects for fruit tree nurseries are huge considering the very large areas of sloping lands, often with bound soils for perennial crops, as trees and shrubs. Currently in Transylvania Region, fruit tree nurseries occupy a percentage of 15.78 % reported to the percentage of tree nurseries in Romania.   The main pathogens identified in Transylvania region at apple and pear nurseries: for Apple nurseries: Apple scab (Venturia Inaequalis), Apple Brown Rot (Monilinia fructigena), Apple powdery mildew (Podosphaera leucotricha) and for pear nurseries: Pear scab (Venturia pirina),  Pear leaf spot (Mycosphaerella sentina), Pear blossom blast (Pseudomonas syringae). This paper aims toi dentify the main pathogens in fruit nurseries in Transylvania, in the context of climate change, and to develop a conceptual model of prevention and control of pathogens attack.

Fusarium spp., Cylindrocarpon spp., and Environmental Stress in the Etiology of a Canker Disease of Cold-Stored Fruit and Nut Tree Seedlings in California.

The principal objective of this study was to determine the etiology of a canker disease in dormant stone fruit and apple tree seedlings maintained in refrigerated storage that has significantly impacted California fruit and nut tree nurseries. Signs and symptoms of the disease develop during storage or soon after planting, with subsequent decline and death of young trees. Isolations from both diseased and healthy almond and apple trees and Koch's postulates using stem segments of desiccation-stressed almond trees as hosts implicated Fusarium avenaceum and F. acuminatum as the primary causal agents. F. solani, Ilyonectria robusta, and Cylindrocarpon obtusiusculum were also capable of causing similar symptoms but were less frequently encountered in isolations of diseased tissue. Loss of bark turgidity in excised almond stem segments, as can occur in cold-stored seedlings, correlated with increased susceptibility to F. acuminatum, with maximum canker development occurring after relative bark turgidity dropped below a threshold of approximately 86%. Healthy almond trees, almond scion budwood, and a wheat cover crop used in fields where tree seedlings were grown and maintained until cold storage all possessed asymptomatic infections of F. acuminatum, F. avenaceum, and C. obtusiusculum as determined by activation following overnight freezing, cold storage, or desiccation.

Economic analysis of fruit tree nurseries in Albania

Production of healthy and certified nursery trees is one of the primary conditions for intensive and stable development of the fruit tree sector. In the last decade, fruit tree production in Albania has drastically increased with more than a thousand hectares per year. The nursery production has attempted to follow with the same pace with about 150 nurseries in the country and more than 2 million nursery trees planted and only 9 percent imported. The purpose of this research, conducted from 2008–2009, was to undertake an economic analysis of these nurseries in view of potential subsidies offered by the government. Thirty-six nurseries were interviewed having quite an intensive production of nursery trees located in the Vlora, Fier, Durres and Tirana regions. Twenty nurseries are specialised, producing only one species of fruit trees, 8 nurseries producing two species and other 8 producing three or four species. The data showed that all the nurseries studied are profitable. On average, their net income is 20000 EUR/farm. The ratio between incomes and costs is 1:0.45. Furthermore, farms producing up to two species of nursery trees have better financial indicators than those producing 3 to 4 species. Moreover, the specialised nurseries have lower costs of more than 3 percent for all categories of nursery trees.

Biotech/GM crops in horticulture: plum cv. HoneySweet resistant to Plum pox virus

Commercialisation of Biotech/GM (Biotech) crops started in 1995. Not only field crops, but also horticultural transgenic crops are under development and are beginning to be commercialised. Genetic engineering has the potential to revolutionise fruit tree breeding. The development of transgenic fruit cultivars is in progress. Over the past 20 years an international public sector research team has collaborated in the development of HoneySweet plum which is highly resistant to Plum pox virus (PPV) the most devastating disease of plums and other stone fruits. HoneySweet was deregulated in the USA in 2010. HoneySweet (aka C5) has been evaluated for eleven years (2002–2012) in a regulated field trial in the CzechRepublic for the resistance to PPV, Prune dwarf virus (PDV), and Apple chlorotic leaf spot virus (ACLSV), all of them being serious diseases of plum. Even under the high and permanent infection pressure produced through grafting, PPV has only been detected in HoneySweet trees in several leaves and fruits situated close to the point of inoculum grafting. The lack of infection spread in HoneySweet demonstrates its high level of PPV resistance. Co-infections of PPV with PDV and/or ACLSV had practically no influence on the quantity and quality of HoneySweet fruit which are large, sweet, and of a high eating quality. In many respects, they are superior to the fruits of the well-known cultivar Stanley. Many fruit growers and fruit tree nurseries in the CzechRepublic are supportive of the deregulation of HoneySweet plum to help improve the plum production and control the spread of PPV.

Feathering of ‘Doyenné du Comice’ pear in the nursery using repeat sprays of benzyladenine and gibberellins

This work sets out to examine the effectiveness of a number of cytokinins or products with cytokinin-like activity, with and without additional sprays of gibberellins or leaf plucking, on the production of feathers (sylleptic shoots) on trees of the European pear cultivar ‘Comice’ in a fruit tree nursery. It covers the results from three successive years experimentation. In year 1, unsprayed trees of ‘Comice’/quince C (QC) had an average of 1.6 useful feathers per tree. Three applications of 1000–2000 mg L −1 benzyladenine (BA) followed by three applications of 400 mg L −1 GA 4+7 resulted in over a fourfold increase in the number of feathers and a fivefold increase in the total length of feathers. Thidiazuron (TDZ) applications of 30–40 mg L −1 followed by three applications of 400 mg L −1 GA 4+7 also resulted in an increase in feathering but were not as effective as BA sprays. Both spray treatments resulted in more spines on the trees. In year 2, feathering of ‘Taylor's Gold Comice’/QC was enhanced by three BA sprays at 1500 mg L −1, followed by three sprays of GA 4+7 at 400 mg L −1. Leaf plucking tended to improve feathering in the absence of GA 4+7. BA sprays were more effective than sprays of TDZ at the concentrations used (30 and 60 mg L −1). Sprays of GA 4+7 without the use of cytokinins also stimulated feathering. Thorniness was linked with the use of GA 4+7, not the cytokinins. In year 3, feathering of ‘Comice’/QC was enhanced by combinations of BA and GA (GA 3 or GA 4+7) sprays (four sprays of each applied sequentially) and these resulted in large, well-feathered trees. Thorniness was associated with the use of gibberellins rather than cytokinins. Thorniness was not reduced by the use of GA 3 over the use of GA 4+7; in fact it was made worse. However, GA 3 was more effective at inducing feathering than GA 4+7, so a similar thorniness score and feathering could be achieved by using 200 mg L −1 GA 3 as achieved with 400 mg L −1 GA 4+7. GA 3 is additionally a cheaper product. Sprays of GA without the use of BA also stimulated feathering, although the height of these feathers in the tree were too high for commercial use because these sprays of GA were applied four weeks later than the BA sprays. Therefore, GA sprays applied earlier in the tree development may be sufficient to feather ‘Comice’ in the absence of BA.

Ensuring Seedling Quality through Fruit Tree Nursery Accreditation and Implications for Forest Nursery Accreditation

he fruit tree nursery accreditation scheme implemented by the Philippine Department of Agriculture has been promoted to enhance the supply of high quality fruit tree planting materials and reduce the number of dubious seedling market players. This paper examines the advantages to participating nurseries in the fruit tree nursery accreditation scheme and draws implications for possible formulation of a scheme to accredit forest tree nurseries in the Philippines. Data were collected from interviews with accredited fruit tree nursery operators and the nursery accreditation officer-in-charge in Northern Mindanao province. A major advantage of nursery accreditation is that only accredited fruit tree nursery operators can participate in the bidding process of the government seedling procurement program, which always involves a substantial volume of seedlings. As a form of advertisement, accredited nurseries are posted on the government website thus creating a wide range of market opportunities which results in increased sales. Other advantages enjoyed by accredited fruit tree nurseries include receiving free training in improving seedling production and occasionally receiving high quality propagation materials (scions and seedlings), subsidies for pesticides and fertilizers and free soil tests. Observations of advantages gained by nursery operators adopting certification have encouraged other nursery operators to apply for accreditation. Accreditation by the Department of Agriculture places emphasis on maintaining high genetic quality as well as high physical quality of planting materials. Accrediting forestry nurseries is seen as a potential policy option that can expand the supply of high quality tree seedlings in the Philippines, as has been the experience with fruit tree nursery certification.

EVALUATION OF PYRUS AND QUINCE ROOTSTOCKS FOR HIGH DENSITY PEAR ORCHARDS

High density planting systems are a prerequisite to economise the use of land and labour costs of orchards. Dwarfing rootstocks controlling the vigour of the scion cultivars form the basis for such orchards (Wertheim and Webster, 2005). In the Netherlands, rootstock research is limited to and focussed on testing rootstocks selected abroad. For the Dutch pear growers the main selection criteria for new rootstocks are: 1) control of tree size; 2) production; 3) fruit size; 4) fruit quality; 5) production efficiency; 6) frost resistance. Additional criteria for Dutch fruit tree nurseries exporting trees to other countries are: 1) compatibility with scion cultivars; 2) suitability for growth in calcareous soils; 3) easy propagation. In all trials rootstock performance is compared to Quince MC, the most commonly used rootstocks for pears in the Netherlands. Recently, a number of Pyrus (Pyrus communis) and Quince (Cydonia oblonga) rootstocks have been tested with ‘Conference’ and ‘Doyenne du Comice’ as the scion cultivars. Generally, the production efficiency of the Pyrus rootstocks was much less than for Quince MC. Another disadvantage of the evaluated Pyrus rootstocks was their high sensitivity towards pear decline. Several rootstocks were rejected after examination of the graft union because of suspected compatibility problems. Of the tested Quince rootstocks C 132 shows promise because of its control of tree growth in combination with good fruit size and Eline® because of its reduction of fruit russeting in ‘Conference’

Molecular diagnosis of Puccinia psidii (guava rust) – a quarantine threat to Australian eucalypt and Myrtaceae biodiversity

A species‐specific, nested polymerase chain reaction (PCR)‐based detection assay, using two primer sets designed from the rRNA ITS region, was developed for Puccinia psidii. Detection sensitivities of one urediniospore alone, or one or two urediniospores in the presence of pollen or leaf tissues, respectively, were observed. The assay reliably, accurately and sensitively detected the rust from naturally infected, geographically widespread eucalypt and fruit tree plantation and nursery species from diverse tissues types (e.g. leaves, flowers, fruits, pollen, seeds and woody material) including symptomless or cryptically contaminated plants or plant tissue. Independent testing in Brazil and Australia demonstrated the international inter‐laboratory transferability of the P. psidii assay required for germplasm screening, disease monitoring and quarantine and incursion management, towards which the assay has already been employed.

Manual and Chemical Inducement of Sylleptic Shoots in Apple in the Fruit-tree Nursery

The ability of various treatments to induce sylleptic shoot development of nursery trees of the apple `Jonagold' and `Golden Delicious' on root-stock M.9 was investigated. The leader management techniques were: removal of sub-terminal leaves, removal of sub-terminal leaves with application of 0.25% Paturyl 10 WSC (6-benzyladenine), and treatment with 0.25% Paturyl 10 WSC (two times at 24 days interval); application of 20% Promalin (GA4+7) two times in 9 days interval; and control; starting when scion length was 75 cm. Removal of sub-terminal leaves increased total branch length, but not stimulated the lateral branching. Treatments with Paturyl resulted in the lower tree height, in the higher number of branches, and in the greater branch length. Removal of sub-terminal leaves in combination with Paturyl increased the lateral shoot number even more than treatment only with Paturyl. Promalin increased branching, but had little influence on the total branch length. In addition, Promalin decreased branch crotch angles.

Molecular Differentiation and Detection of Ginseng-Adapted Isolates of the Root Rot Fungus Cylindrocarpon destructans

ABSTRACT The soilborne fungus Cylindrocarpon destructans (teleomorph: Neonectria radicicola) causes root rot in a wide range of plant hosts; the disease is of particular concern in ginseng production, and in conifer and fruit tree nurseries. beta-Tubulin gene and rRNA gene internal transcribed spacer (ITS) sequence data and pathogenicity assays were used to characterize isolates of C. destructans from ginseng and other hosts. The results of these studies demonstrated a high amount of sequence divergence among strains identified as C. destructans or N. radicicola, suggesting the existence of several phylogenetic species in this complex. Accordingly, we propose that the two varieties of N. radicicola be raised to species status. Certain highly aggressive ginseng isolates from Ontario, Korea, and Japan have identical ITS and beta-tubulin sequences, and form a monophyletic clade (designated "clade a"); these strains are identified as C. destructans f. sp. panacis. Other ginseng strains clustered in monophyletic groups with strains from angiosperm and conifers. A subtractive hybridization method was used to isolate genomic DNA sequences with diagnostic potential from the aggressive C. destructans Ontario ginseng isolate 1640. One of these sequences was similar to the rRNA gene intergenic spacer from a Fusarium oxysporum isolate from Pinus ponderosa, and hybridized to DNA from F. oxysporum and all C. destructans isolates tested. Primers were designed that could be used to amplify this sequence specifically from the highly aggressive, ginsengadapted C. destructans isolates from Ontario and Korea and other members of clade a.

Theory of Garden Art by C. C. L. Hirschfeld

79 varied’’ lives of businessmen in the seventeenth and eighteenth centuries. ‘‘The patriarchal family and kinship networks coexisted with possessive individualism. Thecapitalistethossurfacedintraditional families alongside conventional social ambitions.’’ Mr. Grassby’s iconoclasm pursues the ‘‘facts’’ so intently that, with the refreshing candor of an ‘‘independent scholar,’’ he sometimes vindicates the work of his targets. As part of his argument that, ‘‘Marriage in thebusinesscommunitydid not just transfer power over women from father to husband,’’he asserts that ‘‘Companionate marriage’’ flourished during his period of study, a position that vindicates Stone’s Family, Sex and Marriage . His work in ‘‘apprenticeship registers ’’ finds women joining ‘‘the cutlers, pewterers, drapers, glasssellers, girdlers, basketmakers, scriveners, gunmakers, weavers, clockmakers, goldsmiths, carpentersand stationers.’’However,thepercentage of women apprentices was so ‘‘tiny,’’ and the ‘‘disadvantage’’they suffered from ‘‘lack of capital’’so great, that he, like any good gender theorist, concludes , ‘‘Apprenticeship brought women into the economy without changing the patriarchal character of society.’’ Perhaps most revealing, as Mr. Grassby moves through the topics of marriage, family, men in business, and women in business, he repeatedly corroborates the demographic analysis that underlies much of Stone’s recent work. Although a period of scientific advancement and increasing material wealth, 1580–1740 also wasatimeofdemographiccrisis.‘‘In the early eighteenth century 45 percent of . . . [London] aldermen had no male issue .’’ ‘‘Of the 1,226 baronetcies created (1611–1800), 55 percent were extinct by 1800, and only 295 existed by 1928; only fourteen of ninety-three families achieved succession in single direct male line, often through grandsons.’’ Whether we find it in Nancy Armstrong’s comments upon the ‘‘dismantling’’of the ‘‘aristocratic body’’or in Michael McKeon’s upon ‘‘categorial instability,’’ the claim that patrilineal succession failed in early modern England underlies many of the cultural, gender, and literary studies of which Mr. Grassby is so suspicious. That he unwittingly spreads the ‘‘virus’’ of which he is so contemptuous hardly diminishes his achievement. Rather, it betokens the purity of his method. This book is a ‘‘must-read’’foranyhistorian or literary critic who wishes to attempt (or rely upon) generalizations about marriage, family, and property in eighteenth-century England. Its great lesson is that such generalizations always risk being ‘‘anachronistic’’ and must be offered cautiously, charily—even by Mr. Grassby himself. Brian McCrea University of Florida C. C. L. HIRSCHFELD. Theory of Garden Art, ed. and trans. Linda B. Parshall.Penn Studies in Landscape Architecture. Philadelphia : Pennsylvania, 2001. Pp. ix ⫹ 496. $59.95; £42. C. C. L. Hirschfeld’s five-volume Theorie der Gartenkunst (1779–1785), one of the most influential and popular books on landscape design published in the later eighteenth century, has never been available in English. (This may be because it appeared simultaneously in French; because large swatches of the book are lifted from British and French treatises and guidebooks; or because others later plundered his work, making it seem less original that it actually is.) Hirschfeld’s Theory is both a hymn of praise to the new, ‘‘natural’’ English gar- 80 den and a critique, not only of ‘‘artificial’’ French gardens but of many contemporary garden practices: mixing Chinese, Moorish, and Gothic styles; ignoring the contours and character of the landscape; building ostentatious structures too big for their context and function. Throughout he advocates simple, expressive gardens , ‘‘free of empty ornamentations and trivial affectations,’’ and ‘‘naturalness improved by a restrained art.’’ While he acknowledges that ‘‘princes’’ are necessary to build the more elaborate gardens, he often sounds as if he and his readers would be happy with a carefullydesigned and tended quarter acre. Unlike many other eighteenth-century garden theorists, Hirschfeld is remarkably eclectic and non-dogmatic: ‘‘In matters that theory has not yet exactly determined , perhaps cannot determine, people follow established linguistic practice ; and we understand and are understood , without tying ourselves to the precision of logic and the stubbornness of an arbitrary terminology.’’ He was a professor of philosophy and aesthetics at the University at Kiel, but also the director of a fruit tree nursery. His publishedwork reflects this unusual marriage of the theoretical and the pragmatic. He criticizes landscape theorists like Whately for elevating ‘‘pure metaphysics’’ over ‘‘feeling ,’’ as well as for giving very little ‘‘practical guidance.’’ He...

A MULTIPURPOSE MACHINE FOR CUTTING VEGETATIVELY PROPAGATED AND SEEDLING ROOTSTOCKS

A multipurpose machine is developed to work in fruit tree nurseries for production of vegetatively-propagated and seedling rootstocks. It is mounted and aggregated to a wheeled tractor class 1,4 t and works in one row of plants. The machine is operated by one tractor driver. The machine cuts back the rootstocks at 40-60 cm, removes the top soil of the processed row to the zone of cutting, cuts off the rootstock roots, collects the cut rootstocks in a strip, levels the bed and cleans the soil from the mother plants cuts. The multipurpose machine for cutting vegetatively-propagated and seedling rootstocks eliminates the manual work, increases planting material production and its quality by improving the mechanical operations, that determine the stock root development and contributes to the full exposing of mother plant cuts to the sun.

667 Apple Rootstocks for the Next Century

Rootstock breeding programs in the United States, the United Kingdom, Germany, Russia, Poland, the Czech Republic, and Japan have all released apple rootstocks in the recent past that are potentially important to the worldwide apple industry in the next century. Several of these programs are continuing to breed new rootstocks. Each program has focused on different breeding objectives, thus giving a wide range of horticultural characteristics among this new group of rootstocks. All programs have focused on the horticulturally important traits of productivity, dwarfing and precocity but certain programs have also emphasized other characteristics such as propagability, stress tolerance, disease resistance or insect resistance. Commercialization of this new group of rootstocks is proceeding at an extremely fast pace due to the worldwide networking of fruit tree nursery companies and the use of plant patents. This presents a large job for research and extension personnel to properly test rootstocks for adaptability to different growing areas before they are planted on a large scale. The national rootstock testing project (NC-140) composed of researchers from most apple growing states and provinces in the U.S. and Canada is collecting rootstocks from around the world and conducting uniform field trials that give performance data from a wide variety of climates and soils. This information becomes the basis for local rootstock recommendations in North America. This presentation reviews the most promising rootstocks from around the world and summarize the research information from North American and worldwide trials.

Anatomical study of the bud union in „Chip" and „T" budded 'Jonagold' apple trees on MM 106 rootstock

The traditional methods for vegetative propagation of apple and its varieties are the T-budding, and the winter grafting, but this latter way is a difficult and expensive procedure.
 In our experiment carried out in the Fruit Tree Nursery Soroksár, the healing process of chip- and T-budded apple trees 'Jonagold' on MM 106 rootstock was studied.
 The budding (T- and Chip-) was made in the first week of August, samples for microscope examination were taken monthly after this time until leaf fall.
 The investigated part of plants was made soft with 48 % HF (hydrogenfluoride), then cross and longitudinal section were made and examined by microscope.
 Based on analysis of microscope pictures in case of Chip-budding, it was established, that development had started quickly after budding on the rootstock and scion too. But the callus originated almost entirely from the rootstock tissue as new parenchyma cells fills the gap between the two components of graft (scion and stock), becoming interlocked and allowing for some passage of water and nutrients between the stock and the scion. This quantity of callus in case of T budding was under the scion buds larger, than the Chip-budded unions, where the thickness of callus mass is uniformly thick round the chip. The large mass of callus pushes the scion bud outwards from the shoot axis, which later results in a larger shoot-curvature above the bud union.
 Following this process on the Chip-budding it can be observed also, that a continuity of the cambium is established between bud and rootstock. Then the newly formed cambium started typical cambial activity, forming new xylem and phloem.
 Later the callus begins to lignify, and it is completed within about 3 months after budding.

Production Systems of Fruit Tree Nurseries to Control Graft-Transmissible Diseases.

Graft transmissible diseases of fruit crops are very important because of the large production losses and the transmission of pathogens to propagated clones. Virus, viroid and prokaryote organisms have been found as the causal agents of many diseases. However, unidentified pathogens still remain in many fruit crops. ELISA, electrophoreses and PCR can detect the characterized pathogens rapidly, but plant indexing is necessary for undermined pathogens. To obtain pathogen-free plants, a heat-treatment is effective to eliminate various pathogens from infected plants, but usually not viroids. Apical shoot-tip-culture or grafting can eliminate viroids as well as other pathogens, except for capillovirus. Methods combining pre-heat treatment and subsequent shoot-tip culture/grafting have been demonstrated for the elimination of known pathogens. Pathogen-free stock plants are usually preserved in protective screen houses. However, additional propagation and nursery production have been accomplished in fields in Japan. Thus, periodic checks or indexing of the mother stocks are needed. Pre-inoculation of bud-sources with protective mild strains of virus has been proved effective to control citrus stem pitting disease caused by aphid-vectored CTV. Disinfection of cutting tools is recommended to prevent viroid transmission, especially in nursery production.

Abscisic Acid as a Potential Deciduous Fruit Tree Nursery Stock Defoliant

Abscisic acid (ABA) was tested as a defoliant for nursery trees of `Bartlett' pear (Pyrus communis L.) and the apple (Malus×domestica Borkh.) cultivars Imperial Gala, Gibson Golden Delicious, Scarlet Spur Delicious, Law Red Rome, Granny Smith, Braeburn, and Red Fuji. ABA was sprayed once or twice, with 1 intervening week, at 500, 1000, or 2000 ppm. Percentage defoliation was assessed at 1-week intervals for 4 weeks. For all cultivars, two applications of 2000 ppm ABA ranked among the most effective treatments for rapid defoliation; this treatment led to at least 95% defoliation for all cultivars. For many cultivars, however, other treatments caused similar defoliation percentages by digging time. All tested cultivars were effectively defoliated (>80%) by two 1000-ppm applications ABA or one 2000-ppm application. One or two 500-ppm applications effectively defoliated `Bartlett', `Gibson Golden Delicious', and `Law Red Rome'. Nursery managers, therefore, need to consider a range of ABA concentrations and alternative application protocols to obtain optimum benefit from ABA. Although ABA shows promise as a defoliant, it lacks government approval for commercial use.