bluuebunny/crossref_metadata_2025 huggingface dataset:
Flax
Authors: Green Allan G. , Singh Surinder P. , Chen Yurong , Dribnenki J.C. Paul
Published: April 2009

Flax (Linum usitatissimum) is an ancient crop grown for either its linen fiber (fiber flax) or its highly polyunsaturated seed oil (linseed). In recent times, the whole seed and the extracted oils have also become highly valued nutritional supplements due to their rich content of lignans and ω‐3 fatty acids. Compared to other more major crops, flax is relatively little studied from the genetic, cytogenetic, and molecular genetic perspectives. Nonetheless, significant achievements in improving yield, agronomics, and disease resistance were made during the 1900s using conventional plant breeding and selection techniques. The natural gene pool for flax is limited toL. usitatissimumand its respective annual and biennial progenitors,L. angustifoliumandL. bienne, which significantly limits the opportunity for further genetic improvement. Consequently, mutation breeding techniques were successfully applied in the 1980s to alter the fatty acid composition of the seed and develop a new low‐linolenic form (Linola) that has been used as an alternative to sunflower and safflower oils in polyunsaturated margarine manufacture. More recently, flax has proven to be highly amenable to genetic transformation using Agrobacterium‐mediated approaches. This capability is likely to provide most of the future achievements in flax improvement in the areas of yield, abiotic stress tolerance, disease resistance, herbicide tolerance, insect tolerance, and diversification of product quality.
Safflower
Authors: Babbar Shashi B. , Kaur Amandeep , Walia Neetika
Published: April 2009

The chapter deals with the biology, breeding, and transgene research of safflower (Carthamus tinctoriusL.), an important source of edible oil rich in unsaturated fatty acids. A brief description of its origin, domestication, introduction to other countries, current distribution, and major uses is followed by details about its habit, habitat, taxonomy, cytogenetics, genetic resources, and economic importance. Traditional breeding of this crop has primarily been carried out to improve the oil yield and quality, develop male sterile lines, and incorporate traits for resistance/tolerance to abiotic and biotic stresses. Because of the assiduous and time‐consuming nature of the traditional breeding, efforts have been initiated to improve this crop by biotechnological methods, especially genetic transformation. Most of these studies are preliminary and demonstrative in nature, except two: one leading to the development of genetically transformed safflower capable of synthesizing insulin in its seeds and the other incorporating a gene coding for a specific esterase, capable of hydrolyzing a phototoxic fromAlternaria carthami, a pathogen causing devastating leaf blight disease of safflower. Besides emphasizing the importance and implications of these studies, transgenes, transformation methods, and selection procedures utilized in such studies have been described. The chapter is concluded by discussing some of the future goals of transgene research on safflower, probable environmental risks because of the products so developed, and possible biosafety measures.
Common Bean
Authors: Aragão Francisco J.L. , Faria Josias C. , Del Peloso Maria J. , Melo Leonardo C. , Brondani Rosana P.V.
Published: April 2009

Common bean (Phaseolus vulgaris) is an important source of protein in the diet of more than 300 million people throughout the world. Studies on the domestication and organization processes of the common bean genetic variability was first based on morphological traits and biochemical markers and over the last years, several research groups have made efforts in the development of microsatellite markers for common bean, those are considered the most informative class of markers. Early efforts to transform common beans demonstrated its susceptibility to Agrobacterium, and some transgenic tissues or organs, such as calli, leaves, meristems, cotyledon, and hypocotyl have been achieved. In 1993, it was the first reportedP. vulgaristransformation, presenting molecular evidences of transgenic progeny. Recently, reproducible systems, based onAgrobacteriumand biolistics process, have been developed to achieve transgenic bean plants routinely. Using these systems, some agronomically important genes have been introduced into common bean, such as: the methionine‐rich 2S albumin gene from Brazil nut,bargene that confers resistance to glufosinate ammonium, LEA protein gene, and genes for resistance to theBean golden mosaic virus(BGMV). Herbicide and BGMV‐resistant plants were the first transgenic common bean plants to be evaluated under field conditions.
Lentil
Authors: Oktem Huseyin A. , Akcay Ufuk Celikkol , Bayrac Abdullah Tahir , Kamci Hamdi , Yucel Meral
Published: April 2009

Lentils are annual pulse legume plants and their cultivation by humans is as old as the agriculture itself. Although they are very important as a high protein source for the people of various countries in the world and they are vulnerable to a range of biotic and abiotic stresses, they received very little research attention for the improvement of nutritional and growth characteristics. This chapter summarizes various genetic transformation studies and plant regeneration methods used for the propagation and genetic improvement of this important crop plant.
Tepary Bean
Authors: Terryn Nancy , Van Montagu Marc , Zambre Mukund , Angenon Geert
Published: April 2009

Within the genusPhaseolus,Phaseolus vulgarisor the common bean is the most important grain legume for direct food use. Four otherPhaseolusspecies are also cultivated, although at a lower scale, namelyP. lunatus(lima bean),P. coccinus(scarlet runner bean),P. polyanthus(year‐long bean), andP. acutifolius, the tepary bean; and the tepary bean is the focus of this chapter. The tepary bean is seen by many as one of the most drought‐tolerant annual legume in the world. It is a minor subsistence crop and, hence, is not very important from an economic point of view. Nevertheless, it has some interesting characteristics. On the one hand, its tolerance to drought, high temperatures, and common bacterial blight has inspired breeders to explore the possibilities of crosses with the common bean,P. vulgaris, for its improvement. On the other hand, the tepary bean is the onlyPhaseolusspecies that can easily be transformed with anAgrobacterium‐based system, and for which several classes of transgenic plants have been described, and hence its coverage in this volume.
Vetch
Authors: Ford Rebecca , Maddeppungeng Andi Munasifah , Taylor Paul W.J.
Published: April 2009

Common vetch,Vicia sativaL, is an annual grain legume species and a member of theVicieaetribe. Generally grown as a mix for hay production or grazing, vetch has considerable potential as a grain and forage legume as the seed contains high protein levels. Although the seed has also been used for human consumption, several common accessions contain β‐cyanolalanine and its γ‐glutamyl peptide derivative, which are neurotoxic to monogastric animals. Traditional breeding methods reduced seed toxin levels from 1.15% to between 0.3% and 0.4% of total seed protein, however, due to accumulative effects, much lower or zero levels are required to ensure safe consumption. This may ultimately be achieved through either blocking the neurotoxin production upstream or enabling the currently inactivated downstream biosynthesis of asparagine. Both approaches require the development of a robust and efficient transgenic and regeneration system. The initial steps toward the development of these systems are outlined in this chapter. A regeneration system was developed using somatic embryonic callus derived from epicotyl regions of etiolated seedlings. AnAgrobacterium‐mediated transformation system was also developed, again with best results from using epicotyl‐derived callus.
Pears
Authors: Malnoy Mickael A. , Chevreau Elisabeth , Bell Richard L. , Dolgov Sergey V. , Aldwinckle Herb S.
Published: April 2009

The first report of transformed apple plants in 1996 raised expectations for new pear cultivars that would be better tasting, healthier, and easier to grow. Although, different traits have now been introduced successfully into pear, no transformed cultivars have yet made it to commercial production. Most early reports on transformed pear described “proof of concept” experiments involving the development of regeneration protocols, and the choice of appropriate promoters and selectable markers. More recently the focus has moved onto functional testing of traits of potential commercial interest. Production traits of interest include bacterial, fungal and pest resistance, dwarfing, propagation, stress resistance, and precocity. This review will consider reports of characters introduced into pear that are useful to growers and consumers, and looks toward future trends, targets, and challenges.
Cherries
Authors: Song Guo‐Qing , Lang Gregory A. , Sink Kenneth C. , Dolgov Sergey V.
Published: April 2009

Genetic transformation will be an increasingly important tool for potential improvement of cultivated cherry species (e.g.,Prunus aviumL.,P. cerasusL., and interspecific rootstocks). To understand the best potential applications of genetic engineering and transformation to overcome current genetic barriers to, and/or improve efficiency of, developing improved genotypes for fruit production and rootstock development, the review begins with pertinent background on cherry cultivation, including species history, origins, botanical features, ploidy levels and genetic linkages, and economic and nutritional importance. Traditional breeding objectives, tools, strategies, and achievements to date are discussed, as well as the limitations of conventional breeding, for sweet cherry, sour cherry, and cherry rootstocks. Subsequently, current information on state‐of‐the‐art cherry regeneration and transformation systems is presented. Most cherry species have been recalcitrant to transformation, primarily due toin vitroregeneration difficulties. Consequently, the various regeneration systems that have been attempted are discussed, including descriptions of the biotic and abiotic factors that have been found to influence plant regeneration, such as genotype and explants, culture media, plant growth regulators, and environmental conditions. Current cherry transformation systems are described, including gene delivery systems, explant tissues for transformation, selection regimes, and regeneration of transgenic plants. Based on the perspective of priorities for transgenes, the review concludes with an outline of some targeted traits for future cherry improvement via genetic transformation, including resistance to specific diseases and insects as well as horticultural characteristics.
Grapes
Authors: Bouquet Alain , Torregrosa Laurent , Iocco Pat , Thomas Mark R.
Published: April 2009

Grapevine (Vitis vinifera) is one of the major fruit crops in the world based on hectares cultivated and economic value, essentially due to the production of wine. The premium quality wines are produced from cultivars that enjoy a high level of consumer acceptance and are firmly entrenched in the market place. Transgenic breeding is attractive when compared to conventional breeding, because it offers a means of inserting new characters, such as disease resistance, into the genome of traditional cultivars without changing any of their other characteristics particularly wine typicity and quality. The aim of this review is to provide an outlook on the usefulness of genetic transformation in grapevine, not only to develop genetically modified cultivars for commercial release, but also as a valuable tool to understand the genetics and mechanisms of plant growth, development, and metabolism. Thus, the availability of improved and efficient techniques of transformation is needed to sustain the current development of grapevine genomics. Even if the future development of transgenic cultivars will depend essentially on a general acceptance of GM plant products by the consumers, it will require a complete and reliable assessment of their environmental and health safety, comparing the potential risks to the expected benefits of their use.
Olive
Authors: Rugini Eddo , Gutiérrez‐Pesce Patricia , Muleo Rosario
Published: April 2009

Biochemical and molecular procedures have been developed for olive genotyping, for taxonomy between cultivated and wild olives, for phylogenetic studies of cultivars, and for identification of usable markers linked to the most important agronomic traits, such as size of the tree, flowering induction, apical dominance, productivity, self‐fertility, quantity and quality of oil and secondary products of fruit, biotic and abiotic resistance. These characters could be introgressed into cultivars by conventional breeding or through transgeny. Successful results by classical breeding are difficult to obtain due to the different flower fertility and the long juvenile period of the progenies. The low efficiency of modern genetic improvement techniques suggests that genetic transformation techniques could speed up the development of new genotypes; however, the development of efficient regeneration methods from mature tissue is the limiting factor for applying this technology, in olive. Transgenic olive plants with modified growth habit and putative induced disease resistance are under filed conditions to test their phenotype. Other attempts of genetic improvement such as clonal selection, mutation through γ‐irradiation, protoplast technology, haploid, changes in ploidy level, somaclonal variation, and somatic hybridization are discussed and reviewed.
Almond
Authors: Oliveira M. Margarida , Miguel Célia , Costa Milene S.
Published: April 2009

Almond evolved in the deserts and central slopes of central and southwest Asia (present China and Iran) and was later distributed by many temperate areas all around the word. Almond is a nut fruit of high economical importance, used in various food products and exploited for its oil in pharmaceutical industry and cosmetics. Being very close to peach and otherPrunusspecies, almond can easily hybridize with these close relatives, which may have led to gene exchange in both directions. Self‐fertility and late blooming are among the most important breeding traits. Almond breeding is presently being supported by biotechnology tools, to track the self‐fertility allele in the progeny among other traits that are being mapped. Although there is not an obvious need for genetic engineering tools in almond breeding, engineering strategies have been developed and transgenic plants were regenerated usingAgrobacterium‐mediated gene transfer. This, however, is still only applicable to a couple of genotypes. At present, the most important use of genetic engineering tools in almond seems to be gene functional studies.
Persian Walnut
Authors: T. Britton Monica , Leslie Charles A. , Dandekar Abhaya M. , McGranahan Gale H. , Caboni Emilia
Published: April 2009

Persian walnut (Juglans regiaL.) has been cultivated for nuts and timber for thousands of years. Commercially, the major centers of production are China, the United States, and Europe. Worldwide, walnut production is valued at over $2 billion per year. Walnuts are very high in nutritional content, containing up to 24% protein and up to 70% fats, most of which are polyunsaturated. Several studies have demonstrated the health benefits derived from a diet that includes walnuts. As is true for many heterozygous tree crops, traditional breeding and selection of new walnut cultivars is slow and resource intensive. Therefore, techniques including micropropagation, somatic embryogenesis, and transgenic technology have been developed to speed the incorporation of desirable traits, such as pest and disease resistance, and to clonally propagate select progeny, speeding up the time in which new cultivars can be released to the growers. Transgenic rootstocks will show the greatest promise. However, it is unlikely that transgenic scion cultivars will be commercially available unless there is widespread consumer acceptance.
Grapefruit
Authors: Grosser Jude W. , Gmitter Frederick G. , Orbovic Vladimir , Moore Gloria A. , Graham James H. , Soneji Jaya , Gonzalez‐Ramos Javier , Mirkov T. Erik , Kayim Mukaddes
Published: April 2009

This chapter summarizes the status of genetic transformation research to improve grapefruit. The chapter begins describing the history, origin, distribution and uses of grapefruit, followed by a discussion of the threats to grapefruit production, and finally a review of efforts to date in grapefruit variety improvement.Agrobacterium‐mediated genetic transformation has become the primary method for improving existing cultivars of grapefruit, and extensive protocols for achieving this as well as information regarding the characterization of resulting transgenic plants are provided. The chapter also provides a detailed review of transgenic grapefruit plants produced to date, with focus on transformation with the various transgenes used for specific trait improvement. These include transformation with: virus‐derived genes for citrus tristeza resistance; trifoliate orange derived genes for tristeza resistance; virus‐derived genes for Citrus psororis virus resistance; spinach defensin (SoD2) and bovine lysozyme (BVLZ) antimicrobial genes for citrus canker resistance; and biosynthetic genes from the carotenoid biosynthetic pathway for fruit quality improvement. Finally, preliminary information on the field evaluation of transgenic grapefruit trees in southern Texas is provided.
Banana and Plantain
Authors: Tripathi Leena , Tripathi Jaindra N. , Tenkouano Abdou , Bramel Paula
Published: April 2009

Bananas and plantains (Musaspp.) are the world's fourth most important food crop after rice, wheat, and maize in terms of gross value of production. They are major staple food and source of income for millions of people in tropical and subtropical regions; particularly in Africa, an area where the green revolution has had little influence. The performance of bananas and plantains can be severely affected by diseases and pests. These are predominantly small‐holders' crops; most growers cannot afford costly chemicals to control pests and diseases. The host plant resistance is the most sustainable approach to counteracting pest and disease pressure. Transgenic technology, together with conventional methods can assist in overcoming these problems in developing improved cultivars of banana and plantain. Some successes in genetic engineering ofMusahave been achieved, enabling the transfer of foreign genes into the plant cells. The transgenic approach shows potential for the genetic improvement of bananas using a wide set of transgenes currently available that may confer resistance to pests and diseases. The use of appropriate constructs may allow the production of pest‐ and disease‐resistant plants in a significantly shorter period of time than using conventional breeding; especially if several traits can be introduced at the same time.
Pineapple
Authors: Ko Hian‐Lien , Sanewski Garth M. , Smith Mike K.
Published: April 2009

Pineapple (Ananas comosus(L.) Merr.) is the third most important tropical fruit in world production after banana and citrus. Despite its commercial importance, only recently have reports on successful transformation been reported. This chapter puts these achievements in perspective with the strengths and limitations of both conventional and transgenic breeding, especially with regard to Smooth Cayenne—the cultivar that dominates world trade in processed products. Pineapples can be transformed by either particle bombardment orAgrobacterium‐mediated gene delivery, and an account of transgene design, regeneration procedures, selection methods, and analyses of transgenic plants are given. A full account of biosafety considerations is also documented and should be of use to those researchers planning field trials with transgenic plants. Finally, the future of pineapple transgenic research is considered from both potential new genes that will be required for more profitable, sustainable production and from a consumer perspective. Obstacles in the road ahead are also discussed.
Mango
Authors: Litz Richard E.
Published: April 2009

The mangoMangifera indicaL. has been in cultivation in South and Southeast Asia for several thousand years, and is considered to be the most important fruit crop of Asia. With few exceptions, all cultivars originated as openly pollinated seedling trees. Many of the mango cultivars of India were selected during the 16th century. Currently, the export trade of mangoes is based on New World selections, for example, “Keitt”, “Tommy Atkins”, etc. The major production problems of mangoes include the fruit disease anthracnose, caused byColletotrichum gloeosporioides, and postharvest losses due to the short shelf life of fruit. Embryogenic cultures have been genetically transformed with genes in the antisense that block ethylene biosynthesis.
Eggplant
Authors: Rajam Manchikatla V. , Rotino Giuseppe L. , Sihachakr Darasinh , Souvannavong Vongthip , Mansur Elisabeth , Kumar Polumetla A.
Published: April 2009

Eggplant (Solanum melongenaL.) is one of the important vegetable crops cultivated in various tropical and temperate parts of the world. There is a wide genetic diversity in the cultivated as well as wild species of eggplant. Although, the cultivated eggplant varieties are susceptible to various diseases and pests as well as abiotic stresses, the wild relatives of eggplant are good source of resistance against biotic and abiotic stresses. Therefore, attempts have been made to introgress these agronomically important traits from wild species to cultivated varieties of eggplant, but with limited success. Nevertheless, eggplant is quite amenable for plant regeneration through cell and tissue culture. Haploidisation, somatic hybridization and gene transfer methods have been well established for this crop. The beneficial traits like resistance to bacterial and fungal wilts have successfully been transferred from wild species to cultivated eggplants by protoplast fusion. However, the development of molecular markers and transgenic eggplants with novel traits is in infancy. Eggplant transgenics for insect resistance, abiotic stress tolerance, and parthenocarpy have been accomplished. More work is needed in this direction to produce eggplant transgenics for other agronomic traits, including disease resistance, nematode resistance, quality and shelf‐life of fruits. Modern biotechnological tools like RNA interference (RNAi) are useful to achieve these goals. The initiation of complete genome sequencing of eggplant is required to discover several useful genes, which can be introduced into eggplant and other crop species for genetic improvement. This chapter reviews the various aspects of eggplant biology, particularly the developments in eggplant biotechnology and future projections.
Peppers
Authors: Liu Wing‐Yee , Kim Byung‐Dong , Kang Byoung‐Cheorl , Harn Chee‐Hark , Jahn Molly
Published: April 2009

Peppers (Capsicumspp.) are cultivated in six continents ranking seventh in the harvested area under vegetable crops in the world. Breeding programs for pepper has been well established in Asia and Europe with increasing number of elite F1 hybrid varieties. Traditional pepper breeding has been focusing on traits such as yield, environment adaptation, fruit color and shape, and disease resistance. However, limited genetic resources for breeding and increasing demand for better pepper varieties require new tools for pepper breeding. Two most important biotechnological tools for crop improvement are plant transformation and molecular marker‐assisted breeding. However, due to the difficulties in transformation of peppers, no genetically modified (GM) pepper varieties have been commercialized. Despite continuous efforts, successful reports of pepper transformation are very limited. Even among the successful groups in pepper transformation, the transformation efficiencies have been very low and the transformation was neither consistent nor reproducible. In this review, we will present a general overview of the genusCapsicumand current status of pepper transformation. In addition, we will introduce one of the successful protocols for pepper transformation at the end of this review.
Leafy Vegetables
Authors: Davey Michael R. , Anthony Paul , Power J. Brian , Lowe Kenneth C.
Published: April 2009

Leafy vegetables constitute an important part of a well‐balanced diet. Lettuce, chicory, and spinach are grown extensively as salad crops, with a range of cultivars being generated by conventional plant breeding. Somatic cell technologies, based on the regeneration of shoots from cultured cells and tissues by organogenesis and/or somatic embryogenesis, underpin conventional breeding through procedures such asin vitropollination, microspore culture, embryo rescue, and exposure of somaclonal variation. Gene transfer techniques are most advanced in lettuce. Somatic hybridization through the fusion of isolated protoplasts has been exploited to circumvent sexual incompatibility barriers to introduce genes from wild species into cultivated lettuce. Transformation, based primarily onAgrobacterium‐mediated DNA delivery, has been used to introduce specific traits into leafy vegetables, particularly in lettuce. Such genes include those for resistance to pests, and tolerance to herbicides and environmental conditions including drought, cold, and salinity. Improving the nutritional value and extending shelf life are other prime targets for genetic manipulation. The use of leafy vegetables as “plant factories” to synthesize high value recombinant proteins is an immediate target for transformation at the nuclear and organelle levels in leafy vegetables.
Sugar Beet
Authors: Smigocki Ann , Campbell Larry , Larson Rebecca , Wozniak Chris
Published: April 2009

Sugar beet (Beta vulgarisL.) is a significant industrial crop of the temperate zone that provides about a third of all sugar consumed in the world. World acreage of sugar beet harvested is currently greater than 7.7 million hectares. Market value of this crop is in the billions of US dollars. The increase in world population taken together with the increased demand for alternative energy sources suggests a growing need for increased production of sugar beet not only as a source of food but also as a source of biofuels. This anticipated demand provides the motivation for development of innovative approaches to augment classical breeding techniques for sugar beet improvement. Transgenic sugar beet has the potential to accelerate the development of adapted productive commercial hybrids. In addition to allowing the transfer of desirable genes from other sugar beet species, genes from unrelated organisms could be utilized in sugar beet improvement. Successful introduction of microbial genes that resulted in resistance to broad‐spectrum herbicides has demonstrated the potential of transgenic sugar beet. Discussed are the possibilities for generating transgenic sugar beet with improved disease and pest resistance and the physiological process related to adaptation, yield, and production of new products of economic value.
Stevia
Authors: Singh Hari P. , Dhir Sarwan K. , Dhir Seema
Published: April 2009

Stevia (Stevia rebaudiana(Bertoni)) is a small bush native to Paraguay. Stevia has been traditionally used as a medicinal herb for hundreds of years in various parts of the world. Stevia leaves are a rich source of a natural sweetener “stevioside” which is up to 300 times sweeter than sucrose. Stevia products are primarily known to be used as artificial low‐calorie sweetener while other important characteristics include antimicrobial, antibacterial, antiviral, and antiyeast activity. However, studies have shown that the stevioside content of leaves can vary substantially (5–20%) between individual plants. Such inherent natural variability could be partially explained by self‐incompatible nature of the flowers. Moreover, it is difficult to increase the commercial scale production by conventional means of sexual seed production due to poor seed germination. In addition, limited vegetative propagation is also a major constraint in Stevia production. The worldwide demand for high potency sweeteners is expected to increase in the near future that implicates developing alternative methods for rapid production of plants with high and uniform yields of sweeteners. Various efforts includingin vitroclonal propagation, gene transfer using cutting edge DNA delivery systems, rapid production and high frequency regeneration of transgenic homogenous population plants have been discussed in detail. Maximizing Stevia production through unconventional methods will unleash its potential to become an important nutritional and therapeutic supplement for the growing natural food market in the future.
Potato
Authors: Bradeen James M. , Carputo Domenico , Douches David S.
Published: April 2009

Potato is an ancient New World crop that today ranks among the world's most important food crops. Potato enjoys a long history of improvement through traditional breeding. Breeders target multiple traits, including resistance to biotic and abiotic stresses and tuber quality. Transformation technologies allow the transfer of genes from wild species or the introduction of novel traits while preserving combinations of desirable traits already associated with commercially profitable potato varieties. Transformation approaches are well developed for potato;Agrobacterium‐mediated transformation is the most commonly utilized method. Donor genes have originated fromSolanumspecies, other plant species, bacteria, and viruses. Transgenic approaches have been utilized to improve stress resistance, tuber quality, and industrial utility. Field tests of transgenic potato have been conducted in many parts of the world. Governmental regulations are in place to ensure the safe field release of transgenic potato. Transgenic approaches aimed at improving disease resistance, tolerance to cold sweetening, and nutritional qualities are likely to continue in the future. Transformation technologies that rely only on plant‐derived DNA without the use of a selectable marker and methods for site‐specific introduction of a transgene are important areas of research and may help to address concerns associated with potato transformation.
Sweet Potato
Authors: Dhir Sarwan K. , Singh Hari P. , Dhir Seema
Published: April 2009

The sweet potato,Ipomoea batatas(L.) Lam., is an important root crop supporting millions of people throughout the tropical regions of the world and recognized as world's seventh most important food crop following wheat, rice, maize, potato, barley, and cassava. Sweet potato can produce more edible energy per hectare per day than wheat, rice, or cassava, and possesses potent antioxidant, antidiabetic, and anti‐inflammatory properties while use of starch and other processed goods (e.g., alcohol, etc.) is more localized, and increasingly provides an additional source of cash for poor. Despite the fact that tremendous improvements have been made in sweet potatoes, very little progress has been made in terms of yield when compared to other crops. The major challenges conventional breeding faces are the existence of extensive inherent genetic variability, presence of cross incompatible genes, and low seed set rates. Genetic transformation using tissue culture/biotechnology is an alternative that is looked on to as a promising tool to achieve such goals. Various gene delivery systems have been used to develop transgenic sweet potato concentrating on a specific trait/character, which includesAgrobacterium‐mediated transformation, electroporation, and biolistic approaches. However, the success of transgenic effort can only be achieved by optimizing a successful regeneration protocol and careful consideration of the likely expected effects of transgenic plants on biodiversity of plants, insects, and humans.
Cassava
Authors: Ihemere Uzoma , Sayre Richard T. , Siritunga Dimuth
Published: April 2009

Cassava is the primary staple crop for over 500 million people, primarily living in the tropical regions of the world. Among crops directly eaten by humans, cassava ranks fifth in consumption. Cassava is a shrubby, perennial, root crop native to Brazil. Under ideal conditions, cassava is capable of producing up to 90 ton roots per hectare containing 20–30% starch by fresh weight. Cassava has one of the highest photosynthetic rates for a C3 plant, and the highest rate of sucrose production of any known plant. Due to its high drought tolerance, ability to grow in poor soils, resistance to generalized herbivores, and ability to harvest roots piecemeal for up to 3 years after planting; cassava has become an important food security crop for many subsistence farmers in the tropics. Cassava has shortcomings, however. Roots deteriorate 2–3 days after harvest and roots and leaves harbor cyanogenic glucosides rendering cassava toxic when not properly processed. Since many cultivars do not flower, cassava is propagated by stem cuttings. Because cassava is clonally propagated, it is an ideal crop for improvement through genetic engineering. Efforts are underway to biofortify cassava to provide a more balanced staple food.
Cotton
Authors: Rathore Keerti S. , Sunilkumar Ganesan , Cantrell Roy G. , Reding H. Keith , Hague Steve
Published: April 2009

Lint obtained from cotton plant represents the most important natural fiber that has been used for over seven millennia to meet the clothing requirement of mankind. In addition to the fiber, the plant also provides seed, linters, and hull that are used for food, feed, and several other diverse applications. The cotton plant is susceptible to a large number of pests and pathogens. Traditionally, its cultivation has relied more heavily on the use of toxic pesticides compared to many other crops. Due to the challenges posed by biotic and abiotic stresses during its cultivation and because of the large number of useful products derived from this plant, cotton offers numerous targets that can be modified through the use of modern biotechnological tools. The first generation of genetically engineered cotton plants, offering insect‐ and herbicide‐resistance traits, have gained rapid and wide acceptance in many cotton‐growing countries around the globe. The chapter provides a comprehensive account of transgenic cotton production, including transformation methods, traits introduced, intellectual property rights, and the regulatory issues involved. A brief overview of history, origin, distribution, taxonomy, economic importance, breeding strategies, and achievements is also presented for this crop.
Cocoa
Authors: Maximova Siela N. , Guiltinan Mark J. , Lock Tan C.
Published: April 2009

Theobroma cacao(the chocolate tree) is a tropical tree crop that provides sustainable income to millions of farmers in developing countries and its seeds are the basis for a multi‐billion dollar chocolate industry. Somatic embryogenesis protocols have been developed for cacao, and plants produced with these methods have been field tested and shown to grow normally. Somatic embryos were used as an explant source for co‐cultivation withAgrobacteriumin the development of a reproducible genetic transformation system. The system has been used to study the function of a cacao chitinase gene and to demonstrate its role in plant defense. Further applications of this technology with cacao are reviewed including the possibility of expressing Bt toxin genes effective in controlling the cocoa pod borer insect pest. While there is a very large potential of this technology to help farmers, it is not clear at this time if the technology will ever be utilized with cacao because of market forces and intellectual property issues. However, transgenic approaches to study gene function in cacao are now possible and can contribute to advances in plant breeding by identification of genes involved in disease resistance and other traits of interest.
Tea
Authors: Mondal Tapan K.
Published: April 2009

Tea is not only the most important nonalcoholic beverage drinks worldwide, but also an important “health drink”. It is served as morning drink for a two‐third of world populace daily. Although conventional breeding and propagation contributed significantly in the last several decades for varietal improvement, due to the limitations of conventional breeding, application of biotechnology becomes an alternative approach. Further, its long life cycle, self‐incompatibility, and high inbreeding depression limit its genetic improvement either via the selection of elites from existing natural populations or by the development of biclonal hybrids. With the era of genomics, several genes from tea and its wild genera have been cloned. Thus genetic transformation of tea is important to overcome the limitations of breeding with the assistance of genomics for increasing productivity with lower cost of production, a need of tea industry today. The present report deals with in‐depth progress of various aspects of genetic transformation from tea and related genera, which will be a valuable information for the workers working on various aspects of

Camellia

biotechnology.
Rubber Tree
Authors: Thulaseedharan Arjunan , Jayashree Radha , Kala Radha G. , Rekha Karumankandathil , Sobha Sankaran , Jayasree Parukuttiyamma K. , Kumari Sreedharan S. , Saleena Alikunju , Venkatachalam Perumal
Published: April 2009

Hevea brasiliensis

(Para rubber tree) is the major source of commercial natural rubber (cis‐1,4‐polyisoprene). Rubber produced in specialized cells called laticifers is one of the most important biological molecules used for the manufacture of about 35000 products. Being a cross‐pollinated perennial tree species, genetic improvement through conventional breeding is a rather slow process. Biotechnology would play an important role in the future of the rubber industry. Plant regeneration via somatic embryogenesis using a variety of explant sources like, integumental tissues, immature anther, immature inflorescences, and leaf explants are well standardized. Many genes controlling important agronomic traits and tissue‐specific promoters have been characterized in rubber.

Agrobacterium

and biolistic‐mediated genetic transformation systems are well established in this crop. Thus, the basic technology for genetic manipulation of rubber plant at the cellular and molecular levels is available, making rubber a suitable crop for genetic engineering. In different laboratories, rubber plants were genetically transformed for recombinant protein production with the gene coding for human serum albumin, immunoglobulin single chain variable fragment, and TB antigen gene. Transgenic rubber plants were also produced with
Mn.SOD
gene to confer tolerance against a variety of environmental stresses and tapping panel dryness. Attempts are also going on to enhance the rubber yield through transgenic approaches. Since, the major harvested products are not used as food material, the biosafety concerns are less for the genetically modified rubber plants.
Medicinal Plants
Authors: Saito Kazuki , Muranaka Toshiya , Sudo Hiroshi , Kojoma Mareshige
Published: April 2009

Plants produce a wide variety of secondary metabolites that are used as pharmaceuticals, food additives, and industrial raw materials. Because chemical syntheses of these metabolites are not feasible in many cases, the extraction of useful secondary metabolites from medicinal plants is in great demand. Transgenic medicinal plants offer new opportunities to enhance both the quantity and quality of the compounds. A unique feature of transgenic studies on medicinal plants compared to those on field crops, vegetables, and ornamental plants is the routine use of hairy root technology. Here, we review recent progress in transgenic studies on medicinal plants such as tropane‐ and nicotine‐producing plants (e.g.,Atropa,Datura,Duboisia,Hyoscyamus,Nicotiana, andScopolia), useful terpenoid‐producing plants (e.g.,Artemisia,Eleutherococcus,Glycyrrhiza, andPanax). Furthermore, transgenic studies onGlycyrrhizaspecies for glycyrrhizin, a natural sweetener, andOphiorrhizaspecies for camptothecin, an antineoplastic alkaloid, are described in detail as case studies.
Ornamentals
Authors: Davey Michael R. , Anthony Paul , Prentice Rosemary , Patel Deval , Power J. Brian , Lowe Kenneth C.
Published: April 2009

The trade of ornamental plants generates substantial revenue worldwide, with molecular and somatic cell technologies providing an important and essential underpinning to conventional breeding approaches. Molecular procedures facilitate the identification of novel germplasms for incorporation into breeding programs involving sexual hybridization, while tissue culture‐based techniques are exploited to micropropagate novel germplasms and to provide the basis essential for genetic manipulation. Procedures for the genetic improvement of ornamentals involve exposure of existing genetic variation (somaclonal variation) through cell and tissue culture, somatic hybridization by the fusion of isolated protoplasts, and transformation byAgrobacteriumor particle bombardment (biolistics)‐mediated gene delivery. Targets for genetic manipulation of ornamental plants include modification of stature and floral characteristics and improved tolerance to pests, diseases, and environmental stress.
Poplars
Authors: Joshi Chandrashekhar P. , Busov Victor , Thammannagowda Shivegowda , Tsai Chung‐Jui , Brunner Amy , Meilan Richard
Published: April 2009

In recent years, poplars have provided some of the useful model systems for studying genetic modifications of trees with the eventual goal of improving economically important and environmentally beneficial traits in commercially important tree species. Current problems with the cost and supply of petroleum products have rejuvenated public interest in using poplars as bioenergy crops. While the fast growth, abundant woody biomass and short rotations are some of the attractive features of poplars from the biomass perspective, its small and well characterized genome and ease of crossing, transformation, and cloning have provided some of the important tools for their biotechnological applications. Significant improvements in quantity and composition of lignicellulosic biomass, herbicide tolerance and pest resistance, growth characteristics, and control of flowering in transgenic poplars are some of the examples of successful combinations of basic and applied sciences. The field performances of such transgenic poplar trees are also currently being intensively studied and due to their relatively longer life span compared to herbaceous crops, extended field trials are necessary to evaluate the economical and ecological impact of genetically modified trees for the benefit of society.
Spruce
Authors: Klimaszewska Krystyna , Séguin Armand , Park Yill‐Sung , Arnerup Jenny , Garcia‐Gil Rosario
Published: April 2009

Over the last decade, the production of transgenic conifers, including spruces, has been greatly facilitated by the advancement in somatic embryogenesis whereby embryogenic tissue is transformed through co‐cultivation withAgrobacterium tumefaciensor DNA‐coated microprojectiles. This has facilitated mass propagation of transgenic plants and the development of robust protocols for the genetic transformation of spruce providing, for the first time, the magnitude‐of‐scale required for implementing functional genomics studies in conifers. Presently, forest genomics research focuses on the identification and characterization of gene function that control major traits and attributes in forest trees. Functional genomic research has provided a greater understanding of the roles of specific genes in trees that will lead to the development of selection tools to accurately identify elite trees, which is particularly important in forestry where tree breeding cycles are very long. In this chapter, we first briefly review the biology of the genusPiceaand subsequently expose practical aspects of conventional breeding. We then examine technical issues related to genetic engineering. Finally, we discuss the biosafety issues and considerations related to the deployment of transgenic trees.
Chestnut
Authors: Maynard Charles A. , Powell William A. , Polin‐McGuigan Linda D. , Viéitez Ana M. , Ballester Antonio , Corredoira Elena , Merkle Scott A. , Andrade Gisele M.
Published: April 2009

Castanea sativa, European chestnut, the only native chestnut species in Europe, was derived from the Turkish Mediterranean gene pool.Castanea dentata, American chestnut, is the largest chestnut species native to North America. Although European and American chestnuts are both susceptible toCryphonectria parasitica, the causal agent of chestnut blight, the former is still a commercially viable species. The American chestnut, however, has been essentially eliminated as both a nut crop and a timber species. European and American chestnuts have been the focus of attention of professional and amateur plant breeders for more than a century. They have been selected for various traits, moved from numerous points of origin, hybridized, and redistributed across the landscape. This comes after centuries of domestication by native peoples of both continents. The American Chestnut Foundation is carrying out the largest and most active breeding program based on backcross breeding between the American chestnut and the blight‐resistant Chinese chestnut (Castanea mollissima). A comparison is made between backcross breeding and genetic engineering in terms of numbers of unknown genes introduced and speed of introducing additional genes. Research to develop transformation systems for American and European chestnut has followed similar paths. For both species, the preferred target tissue is somatic embryos derived from immature zygotic embryos. The selectable marker genebar, with the herbicide Finale® (active ingredient phosphinothricin), in combination with scorable markergfp, has proved to be effective in selecting for transformation events in American chestnut. ThenptIIselectable maker gene with kanamycin in combination with the scorable markerguswas used to transform European chestnut. Transgenic whole plants have been recovered for both species. The first two transgenic American chestnuts were planted in the field on June 7, 2006 in Syracuse, New York, USA. These trees contain the oxalate oxidase (OxO) gene originating from wheat, which has been shown to enhance pathogen resistance in several crop species including soybean, peanut, and sunflower.
Casuarinaceae
Authors: Diouf Diaga , Sy Mame‐Ourèye , Gherbi Hassen , Bogusz Didier , Franche Claudine
Published: April 2009

The woody dicotyledonous familyCasuarinaceaeincludes more than 90 species of trees and shrubs that can fix atmospheric nitrogen when nodulated by the soil actinomyceteFrankia.Casuarinaceaeoriginates from Australia, the islands of Pacific and Southeast Asia, and several species have been planted extensively in tropical and subtropical areas of the world for multiple uses, including fuelwood, windbreaks, soil improvement, and coastal dune stabilization. Improving the yield and adaptability of Casuarina trees to biotic and abiotic stresses is an important task. The approaches developed include the selection of species and provenances, conventional plant breeding of host plants with superior performance, and techniques based on tissue culture and vegetative propagation. More recently, some biotechnological tools have been developed that pave the way for genetic engineering of these valuable tropical trees. Transgenic plants of the two speciesCasuarina glaucaandAllocasuarina verticillatahave been obtained using the biological vectorsAgrobacterium tumefaciensandAgrobacterium rhizogenes. Furthermore, the expression conferred by different constitutive or tissue‐specific promoters has been studied in transgenicCasuarinaceaetrees, making it possible to introduce and control the expression of valuable traits in these tropical trees.