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Book Eastern Filbert Blight in Hazelnut  Corylus Avellana

Download or read book Eastern Filbert Blight in Hazelnut Corylus Avellana written by Vidyasagar R. Sathuvalli and published by . This book was released on 2011 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: European hazelnut, Corylus avellana L., is the only economically important nut crop in the family Betulaceae. One of the threats to the hazelnut industry in the Pacific Northwest is the fungal disease eastern filbert blight (EFB) caused by the pyrenomycete Anisogramma anomala. Host genetic resistance to EFB identified in the obsolete pollinizer 'Gasaway' has been extensively used in the hazelnut breeding program at Oregon State University. Concern over deployment of a single resistance gene prompted a search for new sources of resistance. Eighty six accessions from ten countries were evaluated for their response to greenhouse inoculation with the pathogen. Nine accessions showed complete resistance. These new sources of EFB resistance have geographically diverse origins and will broaden the genetic base of our EFB-resistant hazelnut germplasm. Map-based cloning of the EFB resistance gene from 'Gasaway' hazelnut was initiated by constructing a BAC library for 'Jefferson' which is heterozygous for resistance. The BAC library was constructed using the cloning enzyme MboI and the vector pECBAC1 (BamHI site). The library consists of 39,936 clones arrayed in 104 384-well microtiter plates with an average insert size of 117 kb and estimated coverage of 12 genome-equivalents. Chromosome walking initiated with eight RAPD markers closely linked to resistance, and extended with two further rounds of walking identified a total of 93 BACs in the resistance region. A high resolution genetic map of the resistance region was created with 51 markers in a mapping population of 1488 seedlings. In parallel, a physical map was constructed. Analysis indicated that the resistance gene is located in a single contig of three BACs (43F13, 66C22 and 85B7). Whole BACs identified in the resistance region (

Book Identifying and Evaluating Eastern Filbert Blight Resistant Hazelnuts  Corylus Spp   in New Jersey

Download or read book Identifying and Evaluating Eastern Filbert Blight Resistant Hazelnuts Corylus Spp in New Jersey written by John Michael Capik and published by . This book was released on 2014 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: Eastern filbert blight (EFB), caused by the fungus Anisogramma anomala (Peck) E. Müller, is a destructive disease of European hazelnut (Corylus avellana). While the wild North American hazelnut, C. americana, only experiences minor symptoms, commercially grown C. avellana is extremely susceptible. Anisogramma anomala, whose range includes much of the U.S. east of the Rocky Mountains, is considered to be the main impediment to commercial hazelnut production in the East. As such, identifying and developing resistant C. avellana germplasm is critical to establishing an industry in this region. To support this goal, several research projects were undertaken. In the first study, 193 clonal hazelnut accessions spanning multiple Corylus species and inter-specific hybrids were examined for their disease response to EFB in New Jersey. In summary, despite the fact that many of the plants were shown to be resistant in Oregon, some accessions developed EFB in New Jersey. These results support previous work that suggests different isolates of the pathogen are present in the eastern U.S., and resistance may not hold up unilaterally. A second study included searching for new sources of resistance to EFB. New hazelnut germplasm was collected from Russia, Poland, and Ukraine and exposed to EFB. After at least five years of exposure, plants were rated for iii the presence of EFB. At completion, 76 trees from 24 seed lots were found to be free of EFB with several trees that also produced excellent quality kernels. The final study was predicated on evaluating known resistant plants for their flowering phenology in New Jersey. Phenological timing of flowering in hazelnuts is critical to ensure complete pollination and high crop yields. Nineteen hazelnut accessions were evaluated compared to daily temperatures over 4 years. Results showed that the accessions followed a similar progression of bloom each year (both staminate and pistillate flowers), which allowed their placement into Early, Mid-, and Late flowering groups. These findings represent the first efforts to report on flowering and bud break phenology in New Jersey, where the winter climate is colder and more variable than that of Oregon and other commercial hazelnut growing regions.

Book Genetic Resistance to Eastern Filbert Blight

Download or read book Genetic Resistance to Eastern Filbert Blight written by Clarice Jean Coyne and published by . This book was released on 1995 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: Eastern filbert blight, caused by Anisogramma anomala (Peck) E. Muller, is a serious threat to hazelnut (Corylus avellana L.) production. Resistant cultivars offer the best control. Screening systems were needed to reliably identify disease, particularly in immune progeny derived from 'Gasaway'. An indirect enzyme-linked immunosorbant assay (ELISA) was developed using polyclonal antibodies obtained from rabbits injected with A. anomala. One-thousand- fold dilutions of the antiserum produced a positive reaction to a 1.7 x 106 dilution of extracts from infected hazelnut but did not react to healthy plants. ELISA was more sensitive and efficient than microscopic detection. Two methods of screening hazelnut for quantitative resistance to eastern filbert blight were compared for their ability to differentiate between genotypes and for correlations between the two protocols. One method utilized a field plot in a randomized block design with inoculated trees planted in the borders as the disease source. The second method was based on exposing three sets of potted clones to high doses of inoculum in 1990 (Pinkerton et al., 1993), 1992-93, and 1993. Disease incidence and proportion of wood cankered as determined by the two methods were significantly correlated in each year of the study. A map of the field plot disease incidence indicates that the inoculum was present throughout the blocks. Additional sources of resistance are desirable. Seedlings of 'Gem' were all susceptible and seedlings of 'Zimmerman' segregated for resistance following greenhouse inoculation. The immunity of 'Gasaway' was confirmed as being conferred by a single dominant gene. Of the species material, clones of C. cornuta var. californica, C. heterophylla, and C. sieboldiana, most C. americana and one C. colurna clone were resistant, as were seedlings of C. cornuta var. cornuta and C americana. C. jacquemontii seedlings were highly susceptible, as were two suspected C. colurna x C avellana hybrids. Five C. americana x C. avellana hybrids were highly resistant. One of C. cornuta var. californica x C. avellana and two of the C. heterophylla x C. avellana hybrids were resistant. These sources of resistance are being used to broaden the genetic base of the breeding program.

Book DNA Markers Linked to Novel Sources of Resistance to Eastern Filbert Blight in European Hazelnut  Corylus Avellana L

Download or read book DNA Markers Linked to Novel Sources of Resistance to Eastern Filbert Blight in European Hazelnut Corylus Avellana L written by Vidyasagar R. Sathuvalli and published by . This book was released on 2007 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: The hundred-year history of the hazelnut industry in the Pacific Northwest is threatened by eastern filbert blight (EFB) caused by the fungus Anisogramma anomala (Peck) E. Müller. Marker-assisted selection (MAS) has been extensively used for 'Gasaway' resistance in the hazelnut breeding program at Oregon State University. Concern over breakdown of this resistance gene offers an incentive to look for new sources of resistance. Three genotypes (OSU 408.040, 'Ratoli' and OSU 759.010) have shown no signs or symptoms of the disease following a series of greenhouse inoculations or exposure of potted trees under structures topped with diseased wood. The objective of this study was to observe segregation for disease response in the offspring of these three novel sources and identify RAPD (Random Amplified Polymorphic DNA) markers linked to resistance. A total of 900 primers was screened for each resistance source using three resistant seedlings, three susceptible seedlings and the parents of a segregating population. The identified RAPD markers were then validated in a second progeny for each resistance source. Selection OSU 408.040, grown from seeds labeled 'Weschcke hybrid' collected at the research farm of the University of Minnesota, transmitted resistance to half of its seedlings. Six RAPD markers (four in repulsion and two in coupling) linked to resistance were identified for the cross OSU 245.098 x OSU 408.040. A linkage map constructed with disease phenotypes, previously identified AFLP markers and newly identified RAPDs spanned a distance of 18 cM. The order of markers was similar in the progeny OSU 474.013 x OSU 408.040. Segregation in two progenies indicated that the Spanish cultivar 'Ratoli' transmits resistance to 50% of its progeny. Four RAPD markers (one in repulsion and three in coupling) were identified for the progeny OSU 665.012 x 'Ratoli'. A linkage map constructed with disease phenotypes, previously identified AFLP markers and newly identified RAPDs spanned a distance of 28 cM. The RAPD marker OPG17-800 is robust, segregates 1:1, and has potential for use in MAS. Selection OSU 759.010 from the Republic of Georgia provides a new source of resistance. Disease scores segregated 3 resistant: 1 susceptible in the progeny OSU 759.010 x SU 653.068, and 1 resistant : 1 susceptible in the progeny OSU 759.010 x SU 665.076. Thirteen RAPD markers (12 in coupling and one in repulsion) linked to resistance were identified and a linkage map was constructed for the first progeny. All markers except OPH12-640 were also present in the second progeny. The markers closely linked to the resistance locus show distorted segregation in both progenies. Segregation ratios suggest simple inheritance for all three sources of resistance, and several RAPDs useful for marker-assisted selection were identified.

Book Plant Breeding Reviews  Volume 45

Download or read book Plant Breeding Reviews Volume 45 written by Irwin Goldman and published by John Wiley & Sons. This book was released on 2021-10-21 with total page 477 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plant Breeding Reviews presents state-of-the-art reviews on plant genetics and the breeding of all types of crops by both traditional means and molecular methods. Many of the crops widely grown today stem from a very narrow genetic base; understanding and preserving crop genetic resources is vital to the security of food systems worldwide. The emphasis of the series is on methodology, a fundamental understanding of crop genetics, and applications to major crops.

Book Investigation of Novel Sources of Genetic Resistance to Eastern Filbert Blight

Download or read book Investigation of Novel Sources of Genetic Resistance to Eastern Filbert Blight written by China F. Lunde and published by . This book was released on 1999 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: To identify novel host genetic resistance to eastern filbert blight, caused by the fungus Anisogramma anomala (Peck) E. Muller, ninety European hazelnut {Corylus avellana L.) varieties and interspecific hybrids (with C. americana Marsh, or C. colurna L.) were screened for response to the eastern filbert blight pathogen after inoculation in a severe greenhouse test. Six varieties were discovered which did not display signs of the pathogen or symptoms of eastern filbert blight: 'Closca Molla', 'Ratoli', 'Yoder #5', 'Potomac', 'Medium Long', and 'Grand Traverse'. Two of these, 'Ratoli' and 'Closca Molla', are minor varieties from Spain and are superior agronomic types to 'Gasaway' which is the principle source of resistance currently being used in the Oregon State University (OSU) breeding program. Further studies are required to ascertain if the genetics of resistance in these newly evaluated varieties is unique. None of the six varieties has the UBC 15200 RAPD marker that segregates with the resistance gene found in 'Gasaway'. Inheritance of resistance to eastern filbert blight also was investigated in 'Zimmerman', a volunteer seedling that was found in 1989 displaying no disease symptoms despite its proximity to a orchard heavily infested with eastern filbert blight. Three progenies were created using 'Zimmerman' as the pollen parent in controlled crosses with three susceptible advanced selections from the OSU breeding program. The 'Zimmerman' progenies were grown from seed, grafted and subjected to the same severe inoculation as for the germplasm survey. The progenies displayed significant deviation from the 1:1 ratio that would be expected if 'Zimmerman' was hetero2ygous for the 'Gasaway' gene. Resistant phenotypes make up about 83% of the populations which indicates that the genetics of resistance in 'Zimmerman' differs at least partially, from that found in 'Gasaway'. The data were congruent with a 3 resistant :1 susceptible ratio which suggests 'Zimmerman' may possess a second, independent resistance gene. Yet, a well-characterized RAPD marker, linked to the resistance gene in 'Gasaway', segregates with the resistant phenotype in all three progeny populations with very little recombination (2 %, 4 %, and 6%). These newly found sources of resistance to eastern filbert blight will aid in the release of resistant cultivars and may increase the stability of genetic resistance to A. anomala.

Book Microsatellite Marker Development  Characterization and Mapping in European Hazelnut  Corylus Avellana L    and Investigation of Novel Sources of Eastern Filbert Blight Resistance in Corylus

Download or read book Microsatellite Marker Development Characterization and Mapping in European Hazelnut Corylus Avellana L and Investigation of Novel Sources of Eastern Filbert Blight Resistance in Corylus written by Gehendra Bhattarai and published by . This book was released on 2015 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: European hazelnut, an important nut crop in Oregon agriculture, is threatened by the fungal disease eastern filbert blight (EFB) caused by Anisogramma anomala (Peck) E. Müller. The hazelnut breeding program at OSU has been working on development of EFB-resistant cultivars. DNA markers allow mapping of traits using segregating progenies and identification of linked markers. The breeding of hazelnuts involves use of DNA markers to genotype individuals and facilitate selection in a procedure known as marker-assisted selection (MAS). This technique is particularly promising in tree crops with a long juvenile phase like the hazelnuts. 'Gasaway' resistance governed by a dominant allele at a single locus was identified and several EFB-resistant cultivars carrying the dominant allele from this source have been released. Infection of 'Gasaway' and some of its offspring by A. anomala isolates has been noted, and indicates an urgent need to investigate new sources of resistance, identify new resistance genes and incorporate them into the breeding effort. New microsatellite markers were developed from the genomic sequence of hazelnut cv. 'Jefferson'. A total of 17,802 simple sequence repeat (SSR) motifs exceeding 15 bp in length and consisting of tri-, tetra-, penta- and hexa- nucleotide repeats were identified in the 'Jefferson' genome. Removal of duplicates, short fragments, repeats at ends, and repeats containing only A's and T's reduced the number of unique fragments to 2,069. Visual inspection of these unique fragments alligned with genome sequences of 7 other accessions in Tablet software identified 489 sequences with variation in number of repeats but with conserved flanking regions. Amplification of a set of 24 diverse accessions and separation on agarose gels led to the development of 366 new polymorphic markers. These were used to genotype 48 diverse accessions using capillary electrophoresis for fragment sizing. An additional 15 parents were also fingerprinted at these new 366 microsatellite loci. Using the mapping population (OSU 252.146 x OSU 414.062), 213 loci were mapped. A dendrogram was constructed which showed a high level of polymorphism in hazelnut. Tightly linked markers were identified for 'Gasaway' resistance and MAS is routinely used. The hazelnut acreage in Oregon is increasing every year with the planting of these new EFB-resistant cultivars. However, concern about disease resistance breakdown prompted an investigation of 12 new EFB resistance sources. Segregating progenies were inoculated by placement of potted trees under an inoculation structure, in the greenhouse, or in the field by tying a diseased branch on each tree. A chi-square goodness-of-fit test was used compare observed with expected segregation ratios. Very few seedlings of Moscow selections N01, N01-06, and N01-07 were resistant and were likely escapes. 'Grand Traverse', C. heterophylla 'Ogyoo', 'Yoder #5', C. americana 'Rush', Moscow N23, N26, N27, and N37 segregated in 1:1 ratio, indicating resistance governed by a single locus and a dominant allele for resistance. 'Uebov' transmitted resistance to only ~15 % of its seedlings. Resistance from 'Uebov', 'Grand Traverse', and C. heterophylla 'Ogyoo' were assigned to LG6 but only 'Uebov' and 'Grand Traverse' were mapped. Resistance from 'Yoder #5', Moscow N27 and C. americana 'Rush' was assigned to LG7. Mapping of the remaining resistance sources will be completed in the future.

Book DNA Markers and Characterization of Novel Sources of Eastern Filbert Blight Resistance in European Hazelnut  Corylus Avellana L

Download or read book DNA Markers and Characterization of Novel Sources of Eastern Filbert Blight Resistance in European Hazelnut Corylus Avellana L written by Brooke C. Peterschmidt and published by . This book was released on 2013 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: European hazelnut is a significant crop in the Pacific Northwest, and the US ranks 4th internationally for hazelnut production. Production in the Pacific Northwest is threatened, however, by the disease eastern filbert blight (EFB) caused by the fungus Anisogramma anomala (Peck) E. Müller. To meet the challenges faced by the hazelnut industry in Oregon and Washington, the breeding program at Oregon State University has focused on developing DNA marker technology and producing EFB resistant cultivars. This study focused on developing new microsatellite markers from hazelnut transcriptome sequences and on disease resistance from three accessions ('Culpla, ' 'Crvenje, ' and OSU 495.072) which showed no disease symptoms following a series of inoculations. DNA markers have been useful in hazelnut breeding for marker-assisted selection, construction of genetic linkage maps, cultivar fingerprinting, and phylogeny studies. Previously developed markers include AFLP, RAPD, ISSR, and microsatellite (SSR) markers developed from enriched libraries and ISSR fragments. This study utilized the transcriptome sequence from 'Jefferson' hazelnut to mine for microsatellites, align with the genomic sequence, design primers, screen for polymorphism, and characterize and map polymorphic markers. A total of 1432 microsatellites were mined from the transcriptome sequence, and the most frequently found motifs were AG (35.8%), AT (13.3%), and AAG (12.7%), and 382 primer pairs were designed. Screening showed that 119 markers were polymorphic, and these were characterized on sets of 50 and 14 accessions. Fifty-three markers that segregated in the mapping population or in three alternate populations were mapped and assigned to linkage groups. A dendrogram showed that accessions clustered mostly according to geographic origin. These results confirm the high level of diversity present in hazelnut, and the markers developed in this study will be useful for further genetics studies in hazelnut. The three EFB resistant parents 'Culpla, ' 'Crvenje, ' and OSU 495.072 were subjected to two inoculation treatments: greenhouse inoculations and exposure under an inoculation structure. The accessions remained free of disease after both treatments. Progeny segregating for resistance were produced. The progeny were inoculated either in the greenhouse or under the structure, and disease response recorded for each individual. DNA was extracted from seedlings, and sets of 32 seedlings from each resistant parent were screened with previously mapped markers using PCR and capillary electrophoresis. All three resistance sources were correlated with marker A614, allowing the resistance loci to be assigned to linkage group (LG) 6. The progeny were then screened with all known microsatellite markers on LG 6, and linkage maps constructed of the marker loci and resistance loci. Markers KG821, LG628, and LG696 are especially close to the resistance loci and will be useful for marker-assisted selection. Although these resistance loci are located in the same region of LG 6 as the 'Gasaway' resistance gene, they are different from 'Gasaway, ' and markers linked to resistance will be useful for introgressing and pyramiding resistance in new cultivars.

Book Pacific Northwest Plant Disease Management Handbook

Download or read book Pacific Northwest Plant Disease Management Handbook written by Jay W. Pscheidt and published by . This book was released on 2007-03 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Identification and Development of PCR based Markers Linked to Eastern Filbert Blight Resistance in Hazelnut

Download or read book Identification and Development of PCR based Markers Linked to Eastern Filbert Blight Resistance in Hazelnut written by Joel W. Davis and published by . This book was released on 1998 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using bulked segregant analysis, five RAPD markers were identified that were linked in coupling to a gene conferring complete resistance to eastern filbert blight caused by Anisogramma anomala (Peck) E. Muller in hazelnut (Corylus avellana L.). Two modified backcross populations were inoculated and scored for resistance to the pathogen and found to segregate in a 1:1 ratio. In the first population, the five markers were linked to the resistance gene at distances of 6.7, 0, 2.0, 2.0, and 2.0 cM. Three of these markers also were linked in coupling in the second population at distances of 6.0, 6.0, and 4.0 cM. Two of these markers were cloned and sequenced, and primers were designed based on the sequence information at the termini of the amplified marker fragments. These primers were used to amplify DNA from both populations and evaluated for their potential use in selecting for resistance among seedlings. One of these cloned markers (SC152800) produced the same polymorphism among both populations and was consistent with the linkage exhibited by the original RAPD marker. These primers were also used to amplify DNA from a collection of germplasm accessions used in the hazelnut breeding program. A fragment of similar size was amplified in all of the resistant germplasm tested, and also in some of the susceptible selections. This marker was shown to have potential for use in marker-assisted selection for breeding hazelnut cultivars resistant to eastern filbert blight.

Book Recent advances in hazelnut  corylus spp

Download or read book Recent advances in hazelnut corylus spp written by Valerio Cristofori and published by Frontiers Media SA. This book was released on 2023-02-08 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Advances in Plant Breeding Strategies  Nut and Beverage Crops

Download or read book Advances in Plant Breeding Strategies Nut and Beverage Crops written by Jameel M. Al-Khayri and published by Springer Nature. This book was released on 2020-01-01 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book examines the development of innovative modern methodologies towards augmenting conventional plant breeding, in individual crops, for the production of new crop varieties under the increasingly limiting environmental and cultivation factors to achieve sustainable agricultural production, enhanced food security, in addition to providing raw materials for innovative industrial products and pharmaceuticals. This Volume 4, subtitled Nut and Beverage Crops, focuses on advances in breeding strategies using both traditional and modern approaches for the improvement of individual plantation crops. Included in Part I, eleven important nut species recognized for their economical and nutritional importance including Almond, Argan, Brazil nut, Cashew nut, Chestnut, Hazelnut, Macadamia, Peanut, Pine nut, Pistachio and Walnut. Part II covers two popular beverage species, coffee and tea. This volume is contributed by 53 internationally reputable scientists from 13 countries. Each chapter comprehensively reviews the modern literature on the subject and reflects the authors own experience.

Book Grow Fruit Naturally

Download or read book Grow Fruit Naturally written by Lee Reich and published by Taunton Press. This book was released on 2012 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: An illustrated guide to planting over thirty fruits using natural methods; with gardening basics; and pruning, pest control, and harvesting tips for each fruit.

Book Wild Crop Relatives  Genomic and Breeding Resources

Download or read book Wild Crop Relatives Genomic and Breeding Resources written by Chittaranjan Kole and published by Springer Science & Business Media. This book was released on 2011-08-27 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wild crop relatives are now playing a significant part in the elucidation and improvement of the genomes of their cultivated counterparts. This work includes comprehensive examinations of the status, origin, distribution, morphology, cytology, genetic diversity and available genetic and genomic resources of numerous wild crop relatives, as well as of their evolution and phylogenetic relationship. Further topics include their role as model plants, genetic erosion and conservation efforts, and their domestication for the purposes of bioenergy, phytomedicines, nutraceuticals and phytoremediation. Wild Crop Relatives: Genomic and Breeding Resources comprises 10 volumes on Cereals, Millets and Grasses, Oilseeds, Legume Crops and Forages, Vegetables, Temperate Fruits, Tropical and Subtropical Fruits, Industrial Crops, Plantation and Ornamental Crops, and Forest Trees. It contains 125 chapters written by nearly 400 well-known authors from about 40 countries.

Book Growing Hybrid Hazelnuts

Download or read book Growing Hybrid Hazelnuts written by Philip Rutter and published by Chelsea Green Publishing. This book was released on 2015 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: Growing Hybrid Hazelnuts is the first comprehensive guide for farmers interested in how to get started growing hybrid hazelnuts, a crop designed from the very outset to address a host of problems with conventional modern agriculture. Once hybrid hazelnuts are established, no plowing, or even cultivation, is necessary. Dramatically improved infiltration rates prevent water from running off of fields, regardless of soil type.

Book Trees II

    Book Details:
  • Author : Y. P. S. Bajaj
  • Publisher : Springer Science & Business Media
  • Release : 2012-12-06
  • ISBN : 364261535X
  • Pages : 636 pages

Download or read book Trees II written by Y. P. S. Bajaj and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'frees contribute a major part of fuel, fodder and fruit, and are an im of bioenergy. They are now needed in large numbers more portant source than ever before for afforestation and social forestry, so that fast-grow ing and multipurpose trees assume great importance. After extensive in discriminate deforestation and rapid depletion of genetic stocks, efforts are now being made to evolve methods for clonal mass propagation of improved and elite trees. Production of short-duration trees with a rapid turnover of biomass, and induction of genetic variability through in vitro manipulation for the production of novel fruit and forest trees, which are high-yielding and resistant to pests and diseases, and trees which display increased photosynthetic efficiency are in demand. These objectives are well within the realm of horticultural and forest biotech nology. Some of the recent advances, such as the regeneration of com plete trees from isolated protoplasts, somatic hybridization, and the Agrobacterium-mediated transformation in various tree species have opened new vistas for the genetic engineering of fruit and forest trees. This book is a continuation of the earlier volume Trees I, and presents 31 chapters on fruit, forest, nut and ornamental trees, such as avocado, pineapple, crabapple, quince, pistachio, walnut, hazelnut, date palm, oil palm, cacao, rubber, maple, sweet-gum, poplars, birches, Chinese tallow, willows, oaks, paper mulberry, rhododendrons, Scots pine, Calabrian pine, Douglas-fir, redwood, ginkgo, cycads and some flowering trees.