Y. P. S. Bajaj – författare

Production of food to meet the demands of an ever-increasing human population in the world is the major task and challenge to agriculture today. The conventional methods of plant breeding alone can no longer cope with the situation. The success of any crop improvement program depends on the extent of genetic variability in the base population, but due to denuding of forests and agricultural land, the naturally occurring pool of germplasm is being depleted. An urgent need is therefore ap­ parent to create new variability and increase the genetic base of agricul­ tural crops. Agricultural biotechnology has progressed to a stage in the produc­ tion of plants where specific characteristics to improve their yield, ap­ pearance, disease-resistance, nutritional quality and adaptation to ad­ verse soil conditions can be built into the seed. This concept of built-in quality implies a continuous scientific endeavour to improve plant char­ acters using a wide range of possibilities, and it also implies a scrutiny of the materials and methods available in the world today.

This volume presents 31 chapters on biotechnology of treesand deals with the importance, distribution, conventionalpropagation, micropropagation, review of tissue culturestudies, and recent advances in the in vitro culture andgenetic manipulation of forest, fruit and ornamental trees.

This richly illustrated volume describes how somatic hybrids can contribute to the improvement of crops. It comprises 24 chapters dealing with interspecific and intergeneric somatic hybridization and cybridization, providing valuable tools for plant breeders.

The incorporation of haploids in breeding programs is one of the latest techniques used for crop improvement. The present volume comprises 30 chapters by international experts and informs on the methods involved, such as in vitro production of haploids by culture of anthers, studies of pollen embryogenesis, genetic analysis of haploids. It also discusses the genetic stability of haploid cell cultures as well as the practical importance of haploids in breeding for the release of new varieties. Results of experiments with wheat, barley, maize, rice, rubber, poplar, apple, litchi, Digitalis, Hyoscyamus, Arabidopsis, asparagus, sugarbeet, cabbage, pepper, carrot, strawberry, Gerbera, sunflower, tomato, alfalfa, winged bean, sugarcane, and Solanum are presented.

This volume contains 37 chapters contributed by international experts. It deals with various aspects of the biotechnology of wheat, including in vitro methods, somatic embryogenesis, micropropagation, wide hybridization and embryo culture, production of haploids and the release of varieties, somaclonal variation and mutations, nutritional improvement, protoplast culture, transient gene expression, and the cryopreservation of germoplasm. Special emphasis has been laid on in vitro production of haploids, somaclonal variation, and wide hybridization. These methods have been sufficiently refined and can now be used by plant breeders to generate genetic variability - a prerequisite for future wheat improvement programmes.

After the 1986 and 1989 volumes, this is the third volume on biotechnology for propagation of trees. Comprising 28 chapters contributed by international experts the book deals with fruit, ornamental, and forest trees, such as Black cherry, Sour cherry, Pomegranate, Loquat, Ficus, Yellow poplar, Horse chestnut, Judas tree, Linden tree, Saskatoons, Taiwan sassafras, Plane-tree, Rattans, Bamboos, Engelmann spruce, White spruce, Larches, Hinoki cypress, Western redcedar, and various types of pines, i.e. Jack, Carribean, Eldarica, Slash, Egg-cone, Maritime, Ponderosa, Eastern white, Loblolly pine. Trees III is an excellent reference book for scientists, educators, and students of forestry, botany, genetics, and horticulture, who are interested in tree biotechnology.

Presenting the state of the art of tissue culture and in vitro propagation of vegetable and tuber crops, medicinal and aromatic plants, fibre and oilseed crops, and grasses, this book complements the previous two volumes on High-Tech and Micropropagation, which concentrated on special techniques (Vol.17) and trees and bushes of commercial value (Vol.18). The specific plants covered here include asparagus, lettuce, horse radish, cucumber, potato, cassava, sweet potato, artichoke, yams, cardamom, fennel, celery, thyme, leek, mentha, turmeric, lavender, agave, yucca, cotton, jute, sunflower, ryegrass, zoysiagrass, and various species of Aconitum, Artemisia, Camelia, Centaurium, Digitalis, Dioscorea, Glehnia, Levisticum, Parthenium, and Pinella. The book is of use to advanced students, teachers and research workers in the field of pharmacy, horticulture, plant breeding and plant biotechnology in general, and also to individuals interested in industrial micropropagation.

In continuation from the previous three volumes 17, 18, and 19 on High-Tech and Micropropagation this volume presents 29 chapters on the propagation of ornamental plants through modern biotechnological methods. The species covered include Alstromeria, Antirrhinum, Begonia, Chrysanthemum, Cornus, Euphorbia, Gardenia, Gladiolus, Hyacinthus, Impatiens, Iris, Lycoris, Nematanthus, Paeonia, Pelargonium, Phalaenopsis, Rhododendron, Ruscus, Saintpaulia, Senecio, Syringa, orchids, cacti, roses, and Boston ferns. In addition, one chapter is devoted to micropropagation of virus-free ornamentals in the CIS. Throughout the book, detailed protocols as well as a comprehensive review of the literature are provided. Advanced students, teachers, and researchers in the fields of floriculture, horticulture, and plant biotechnology in general, and also those interested in industrial or commercial micropropagation will find a wealth of useful information in the book.

27 chapter cover the distribution, economic importance,conventional propagation, micropropagation, tissue culture,and in vitro production of important medicinal andpharmaceutical compounds in various species of Ajuga,Allium, Ambrosia, Artemisia, Aspilia, Atractylodes,Callitris, Choisya, Cinnamomum, Coluria, Cucumis, Drosera,Daucus, Eustoma, Fagopyrum, Hibiscus, Levisticum,Onobrychis, Orthosiphon, Quercus, Sanguinaria, Solanum,Sophora, Stauntonia, Tanecetum, Vetiveria, and Vitis.Like the previous volumes 4, 7, 15, and 21 in theMedicinal and Aromatic Plants series, the volume istailored to the need of advanced students, teachers,and research scientists in the area of plant biotechnologyandbioengineering, pharmacy, botany and biochemistry.

Forty chapters deal with various aspects of tissue culture, in vitro manipulation, and other biotechnological approaches to the improvement of maize. They are arranged in eight sections: - In Vitro Technology, Callus Cultures and Regeneration of Plants, Somatic Embryogenesis. - Wide Hybridization, Embryo, Ovule, and Inflorescence Culture, in Vitro Fertilization. - Production of Haploids and Double Haploids, Anther and Pollen Culture. - Protoplast Culture, Genetic Transformation. - Somaclonal Variation and Mutations. - Molecular Biology and Physiological Studies. - Proteins and Nutritional Improvement. Pollen Storage, Cryopreservation of Germplasm.

Fantasies and dreams have their rightful place in science, and sometimes they turn into reality. Regeneration of hybrid plants through protoplast fusion is one such dream come true. In the early 1970s I shared the pioneering excitement in the field of protoplast technology at the Second International Congress of Plant Tissue Culture held in Strasbourg, France. Subsequently, I participated in three international conferences devoted to plant protoplasts, in Salamanca, Spain (1972), Versailles, France (1972), and Nottingham, England (1975). At Versailles Dr. P.S. Carlson presented his work on the successful regeneration of somatic hybrids between Nicotiana glauca and Nicotiana langsdorfii. The enthusi- asm shown by the participants was sufficient indication of the bright future of somatic hybridization. On my return from Versailles, I gathered my thoughts and prepared a concept paper on Potentials of Protoplast Culture Work in Agriculture which was published in Euphytica (Bajaj 1974). The studies on protoplast fusion and somatic hybridization then gained momentum and active work started in many laboratories. Very significant work was done by Melchers et al.(1978) who obtained a somatic hybrid between potato and tomato, calling it "Pomato".

Whole plants have been regenerated from isolated protoplasts, cells, tissues, and organs freeze-preserved in liquid nitrogen. Thus cryopreservation has proved to be an important tool for the storage and conservation of plant genetic resources. Numerous experts have contributed to this volume, which is divided into the following sections: General introduction into the cryopreservation of plant cells, tissues, organs and seeds; trees; cereals and grasses; legumes and oilseed crops; fruits, vegetables, tuber and root crops; medicinal, aromatic and ornamental plants.

Plant protoplasts have proved to be an excellent tool for in vitro manipu- lations, somatic hybridization, DNA uptake and genetic transformation, and for the induction of somaclonal variation. These studies reflect the far- reaching impact of protoplast alterations for agriculture and forest bio- technology. Taking these aspects into consideration, the series of books on Plant Protoplasts and Genetic Engineering provides a survey of the litera- ture, focusing on recent information and the state of the art in protoplast Plant Protoplasts manipulation and genetic transformation. This book, and Genetic Engineering VI, like the previous five volumes published in 1989,1993, and 1994, is unique in its approach. It comprises 27 chapters dealing with the regeneration of plants from protoplasts, and genetic transformation in various species of Arachis, Bupleurum, Capsella, Dendrobium, Dianthus, Diospyros, Fagopyrum, Festuca, Gentiana, Glycyrrhiza, Gossypium, Hemerocallis, Levisticum, Lonicera, Musa, Physallis, Platanus, Prunus, Saposhnikovia, Solanum, Spinacia, Trititrigia, Tulipa, and Vaccinium; including fruits such as apricot, banana, cranberry, pepino, peach, and plum.This book may be of special interest to advanced students, teachers, and research scientists in the field of plant tissue culture, molecular biology, genetic engineering, plant breeding, and general bio- technology. New Delhi, August 1995 Professor Y. P. S. BAJA] Series Editor Contents Section I Regeneration of Plants from Protoplasts 1. 1 Regeneration of Plants from Protop1asts of Arachis Species (Peanut) Z. LI, R. L. JARRET, and J. W. DEMSKI (With 2 Figures) 1 Introduction ...3 2 Isolation of Pro top lasts ...4 3 Culture of Protoplasts ...

This book Trees IV, like the previous volumes (Trees I, II, III published in 1986, 1989, 1991, respectively), is special in its approach. It elucidates the case history and biotechnology of individual fruit, forest, and ornamental trees, and discusses the present state of the art, with particular reference to in vitro propagation. It comprises 24 chapters contributed by international experts, and deals with the importance, distribution, conventional propa- gation, micropropagation, review of tissue culture studies, and recent advances in the in vitro culture and genetic manipulation of various species of Acrocomia, Ailanthus, Anacardium, Allocasuarina, Carya, Casuarina, Coffea, Cyphomandra, Feijoa, Fraxinus, Gymnocladus, Leptospermum, Fagus, Metroxylon, Oxydendrum, Paeonia, Paulownia, Pouteria, Psidium, and Quercus. Included are also five chapters on gymnosperm trees, such as Abies jraseri, Cephalotaxus harringtonia, Pinus durangensis, P. gregg ii, P. halepensis, P. pinea, and Tetraclinis articulata.Trees IV is a valuable reference book for scientists, teachers, and students of forestry, botany, genetics, and horticulture, and all those who are interested in the biotechnology of trees. New Delhi, March 1996 Professor y. P. S. BAJAJ Series Editor Contents Section I Angiosperm Trees 1. 1 Acrocomia Species (Macauba Palm) O. l. CROCOMO and M. MELO (With 8 Figures) 1 General Account ...3 2 Chemical Composition ...5 3 Genetics and Crop Improvement 9 4 In Vitro Culture Studies 10 5 Industrial Utilization ...14 6 Lauric Acid ...15 7 Summary and Conclusions 15 References ...16 1. 2 Ailanthus altissima Mill. Swingle (Tree of Heaven) M. ZENKTELER and B.

This volume comprises twenty-four chapters dealing with the distribution, importance, conventional propagation, micropropagation, tissue culture studies, and the in vitro production of important medicinal and pharmaceutical compounds in various species of Agave, Anthemis, Aralia, Blackstonia, Catha, Catharanthus, Cephalocereus, Clerodendron, Coronilla, Gloeophyllum, Liquidambar, Marchantia, Mentha, Onosma, Paeonia, Parthenium, Petunia, Phyllanthus, Populus, Portulaca, Sandersonia, Serratula, Scoparia, and Thapsia. It is tailored to the needs of advanced students, teachers, and research scientists in the field of pharmacy, plant tissue culture, phytochemistry, biochemical engineering, and plant biotechnology in general.

Plant protoplasts have proved to be an excellent tool for in vitro manipulation, somatic hybridization, DNA uptake and genetic trans- formation, and for the induction of somac1onal variation. These studies reflect the far-reaching impact of protoplast research in agriculture and forest biotechnology. Taking these aspects into consideration, the series of books on Plant Protoplasts and Genetic Engineering provides a survey of the literature, focusing on recent information and the state of the art in protoplast manipulation and genetic transformation. This book, Plant Protoplasts and Genetic Engineering VII, like the previous six volumes published in 1989, 1993, 1994, and 1995, is unique in its approach. It comprises 27 chapters dealing with the regeneration of plants from protoplasts, and genetic transformation in various species of Agrostis, Allium, Anthriscus, Asparagus, Avena, Boehmeria, Carthamus, Coffea, Funaria, Geranium, Ginkgo, Gladiolus, Helianthus, Hordeum, Lilium, Lithospermum, Mentha, Panax, Papaver, Passiflora, Petunia, Physcomi- trella, Pinus, Poa, Populus, Rubus, Saintpaulia, and Swertia.This book may be of special interest to advanced students, teachers, and research scientists in the field of plant tissue culture, molecular biology, genetic engineering, plant breeding, and general biotechnology. New Delhi, June 1996 Professor y. P. S. BAJAJ Series Editor Contents Section I Regeneration of Plants from Protoplasts 1. 1 Regeneration of Plantlets from Protoplasts of Allium cepa (Onion) E. E. HANSEN, J. F. HUBSTENBERGER, and G. C. PHILLIPS (With 3 Figures) 1 Introduction ...3 2 Protoplast Isolation ...4 3 Protoplast Culture ...8 4 Regeneration of Plantlets ...9 5 Summary...

This volume, fifth in the series High-Tech and Micropropagation, contains 24 chapters arranged in the following three sections:I. Vegetables and Fruits: garlic, Amaranthus, Brassica oleracea, pepper, watermelon, cassava, banana, Myrtus communis, passionfruit, Polymnia sonchifolia, pepino, and spinach.II. Grasses: bamboos, Caustis dioica, Dendrocalamus, Miscanthus x giganteus, sugarcane.III. Trees: Aegle marmelos, Eucalyptus, Fraxinus excelsior, Juglans cinerea, Pinus virginiana, Prosopis, and Ulmus. This book is of use to research workers, advanced students, and teachers in the fields of horticulture, forestry, botany, and plant biotechnology in general, and also to individuals interested in industrial micropropagation.

Wheat, which is the second most important cereal crop in the world, is being grown in a wide range of climates over an area of about 228 945 thou­ sand ha with a production of about 535 842 MT in the world. Bread wheat (Triticum aestivum L. ) accounts for 80% of the wheat consumption, howe­ ver, it is attacked by a large number of pests and pathogens; rusts and smuts cause enormous damage to the crop and reduce the yield drastically in some areas. The major breeding objectives for wheat include grain yield, earliness, resistance to lodging and diseases, spikelet fertility, cold tolerance, leaf duration and net assimilation rate, fertilizer utilization, coleoptile length, nutritional value, organoleptic qualities, and the improvement of charac­ ters such as color and milling yield. The breeding of wheat by traditional methods has been practiced for centuries, however, it has only now come to a stage where these methods are insufficient to make any further breakthrough or to cope with the world's demand. Although numerous varieties are released every year around the world, they do not last long, and long-term objectives cannot be realized unless more genetic variability is generated. Moreover, the intro­ duction of exotic genetic stocks and their cultivation over large areas results in the depletion and loss of the native germplasm pool.

After the 1986 and 1989 volumes, this is the third volume on biotechnology for propagation of trees. Comprising 28 chapters contributed by international experts the book deals with fruit, ornamental, and forest trees, such as Black cherry, Sour cherry, Pomegranate, Loquat, Ficus, Yellow poplar, Horse chestnut, Judas tree, Linden tree, Saskatoons, Taiwan sassafras, Plane-tree, Rattans, Bamboos, Engelmann spruce, White spruce, Larches, Hinoki cypress, Western redcedar, and various types of pines, i.e. Jack, Carribean, Eldarica, Slash, Egg-cone, Maritime, Ponderosa, Eastern white, Loblolly pine. Trees III is an excellent reference book for scientists, educators, and students of forestry, botany, genetics, and horticulture, who are interested in tree biotechnology.

Presenting the state of the art of tissue culture and in vitro propagation of vegetable and tuber crops, medicinal and aromatic plants, fibre and oilseed crops, and grasses, this book complements the previous two volumes on High-Tech and Micropropagation, which concentrated on special techniques (Vol.17) and trees and bushes of commercial value (Vol.18). The specific plants covered here include asparagus, lettuce, horse radish, cucumber, potato, cassava, sweet potato, artichoke, yams, cardamom, fennel, celery, thyme, leek, mentha, turmeric, lavender, agave, yucca, cotton, jute, sunflower, ryegrass, zoysiagrass, and various species of Aconitum, Artemisia, Camelia, Centaurium, Digitalis, Dioscorea, Glehnia, Levisticum, Parthenium, and Pinella. The book is of use to advanced students, teachers and research workers in the field of pharmacy, horticulture, plant breeding and plant biotechnology in general, and also to individuals interested in industrial micropropagation.

Whole plants have been regenerated from isolated protoplasts, cells, tissues, and organs freeze-preserved in liquid nitrogen. Thus cryopreservation has proved to be an important tool for the storage and conservation of plant genetic resources. Numerous experts have contributed to this volume, which is divided into the following sections: General introduction into the cryopreservation of plant cells, tissues, organs and seeds; trees; cereals and grasses; legumes and oilseed crops; fruits, vegetables, tuber and root crops; medicinal, aromatic and ornamental plants.

This book Trees IV, like the previous volumes (Trees I, II, III published in 1986, 1989, 1991, respectively), is special in its approach. It elucidates the case history and biotechnology of individual fruit, forest, and ornamental trees, and discusses the present state of the art, with particular reference to in vitro propagation. It comprises 24 chapters contributed by international experts, and deals with the importance, distribution, conventional propa- gation, micropropagation, review of tissue culture studies, and recent advances in the in vitro culture and genetic manipulation of various species of Acrocomia, Ailanthus, Anacardium, Allocasuarina, Carya, Casuarina, Coffea, Cyphomandra, Feijoa, Fraxinus, Gymnocladus, Leptospermum, Fagus, Metroxylon, Oxydendrum, Paeonia, Paulownia, Pouteria, Psidium, and Quercus. Included are also five chapters on gymnosperm trees, such as Abies jraseri, Cephalotaxus harringtonia, Pinus durangensis, P. gregg ii, P. halepensis, P. pinea, and Tetraclinis articulata.Trees IV is a valuable reference book for scientists, teachers, and students of forestry, botany, genetics, and horticulture, and all those who are interested in the biotechnology of trees. New Delhi, March 1996 Professor y. P. S. BAJAJ Series Editor Contents Section I Angiosperm Trees 1. 1 Acrocomia Species (Macauba Palm) O. l. CROCOMO and M. MELO (With 8 Figures) 1 General Account ...3 2 Chemical Composition ...5 3 Genetics and Crop Improvement 9 4 In Vitro Culture Studies 10 5 Industrial Utilization ...14 6 Lauric Acid ...15 7 Summary and Conclusions 15 References ...16 1. 2 Ailanthus altissima Mill. Swingle (Tree of Heaven) M. ZENKTELER and B.

This volume comprises twenty-four chapters dealing with the distribution, importance, conventional propagation, micropropagation, tissue culture studies, and the in vitro production of important medicinal and pharmaceutical compounds in various species of Agave, Anthemis, Aralia, Blackstonia, Catha, Catharanthus, Cephalocereus, Clerodendron, Coronilla, Gloeophyllum, Liquidambar, Marchantia, Mentha, Onosma, Paeonia, Parthenium, Petunia, Phyllanthus, Populus, Portulaca, Sandersonia, Serratula, Scoparia, and Thapsia. It is tailored to the needs of advanced students, teachers, and research scientists in the field of pharmacy, plant tissue culture, phytochemistry, biochemical engineering, and plant biotechnology in general.

Plant protoplasts have proved to be an excellent tool for in vitro manipulation, somatic hybridization, DNA uptake and genetic trans- formation, and for the induction of somac1onal variation. These studies reflect the far-reaching impact of protoplast research in agriculture and forest biotechnology. Taking these aspects into consideration, the series of books on Plant Protoplasts and Genetic Engineering provides a survey of the literature, focusing on recent information and the state of the art in protoplast manipulation and genetic transformation. This book, Plant Protoplasts and Genetic Engineering VII, like the previous six volumes published in 1989, 1993, 1994, and 1995, is unique in its approach. It comprises 27 chapters dealing with the regeneration of plants from protoplasts, and genetic transformation in various species of Agrostis, Allium, Anthriscus, Asparagus, Avena, Boehmeria, Carthamus, Coffea, Funaria, Geranium, Ginkgo, Gladiolus, Helianthus, Hordeum, Lilium, Lithospermum, Mentha, Panax, Papaver, Passiflora, Petunia, Physcomi- trella, Pinus, Poa, Populus, Rubus, Saintpaulia, and Swertia.This book may be of special interest to advanced students, teachers, and research scientists in the field of plant tissue culture, molecular biology, genetic engineering, plant breeding, and general biotechnology. New Delhi, June 1996 Professor y. P. S. BAJAJ Series Editor Contents Section I Regeneration of Plants from Protoplasts 1. 1 Regeneration of Plantlets from Protoplasts of Allium cepa (Onion) E. E. HANSEN, J. F. HUBSTENBERGER, and G. C. PHILLIPS (With 3 Figures) 1 Introduction ...3 2 Protoplast Isolation ...4 3 Protoplast Culture ...8 4 Regeneration of Plantlets ...9 5 Summary...

Fantasies and dreams have their rightful place in science, and sometimes they turn into reality. Regeneration of hybrid plants through protoplast fusion is one such dream come true. In the early 1970s I shared the pioneering excitement in the field of protoplast technology at the Second International Congress of Plant Tissue Culture held in Strasbourg, France. Subsequently, I participated in three international conferences devoted to plant protoplasts, in Salamanca, Spain (1972), Versailles, France (1972), and Nottingham, England (1975). At Versailles Dr. P.S. Carlson presented his work on the successful regeneration of somatic hybrids between Nicotiana glauca and Nicotiana langsdorfii. The enthusi- asm shown by the participants was sufficient indication of the bright future of somatic hybridization. On my return from Versailles, I gathered my thoughts and prepared a concept paper on Potentials of Protoplast Culture Work in Agriculture which was published in Euphytica (Bajaj 1974). The studies on protoplast fusion and somatic hybridization then gained momentum and active work started in many laboratories. Very significant work was done by Melchers et al.(1978) who obtained a somatic hybrid between potato and tomato, calling it "Pomato".

Forty chapters deal with various aspects of tissue culture, in vitro manipulation, and other biotechnological approaches to the improvement of maize. They are arranged in eight sections: - In Vitro Technology, Callus Cultures and Regeneration of Plants, Somatic Embryogenesis. - Wide Hybridization, Embryo, Ovule, and Inflorescence Culture, in Vitro Fertilization. - Production of Haploids and Double Haploids, Anther and Pollen Culture. - Protoplast Culture, Genetic Transformation. - Somaclonal Variation and Mutations. - Molecular Biology and Physiological Studies. - Proteins and Nutritional Improvement. Pollen Storage, Cryopreservation of Germplasm.

27 chapter cover the distribution, economic importance, conventional propagation, micropropagation, tissue culture, and in vitro production of important medicinal and pharmaceutical compounds in various species of Ajuga, Allium, Ambrosia, Artemisia, Aspilia, Atractylodes, Callitris, Choisya, Cinnamomum, Coluria, Cucumis, Drosera, Daucus, Eustoma, Fagopyrum, Hibiscus, Levisticum, Onobrychis, Orthosiphon, Quercus, Sanguinaria, Solanum, Sophora, Stauntonia, Tanecetum, Vetiveria, and Vitis. Like the previous volumes 4, 7, 15, and 21 in the Medicinal and Aromatic Plants series, the volume is tailored to the need of advanced students, teachers, and research scientists in the area of plant biotechnology andbioengineering, pharmacy, botany and biochemistry.

In continuation of Somaclonal Variation and Crop Improvement I (1990), this volume is comprised of twenty-four chapters dealing with somaclonal variants showing resistance to salt drought, herbicides, viruses, Alternaria, Fusarium, Glomerella, Verticillium, Phytophthora, fall armyworm, etc. in a number of plants of economic importance. It is divided into two sections: Section I. Somaclonal Variation in Agricultural Crops: wheat, rice, maize, sorghum, potato, tomato, Lotus, Stylosanthes, banana, strawberry, citrus, colt cherry. Section II. Somaclonal Variation in Medicinal and Aromatic Plants: Atropa, Carthamus, Hypericum, Lavatera, Nicotiana, Primula, Rauwolfia, scilla, and Zinnia.

Haploid plants have the gametophytic number of chromosomes. They are of great importance, especially in studies on the induction of muta­ tions and also for the production of homozygous plants, they are needed in large numbers. The conventional methods employed by plant breeders for their production are cumbersome, time-consuming, laborious and rather inefficient. Sometimes it may take years to produce a pure line. However, with the introduction of in vitro techniques, especially anther culture for the induction of androgenesis, it has become increasingly evi­ dent that these methods considerably accelerate the production of haploids for plant breeding programs. During the last decade, in vitro-produced haploids have been incor­ porated into breeding programs of many agricultural crops, and positive results have been obtained especially with rice, wheat, potato, barley, maize, asparagus, sunflower, brassica, tobacco, etc. Among these, rice and wheat are the best examples in which a number of improved varieties have been released. In wheat, the breeding cycle can be shortened by three or four generations when the pollen haploid breeding method is used instead of conventional cross-breeding. The release of the wheat varieties Jinghua 1 and Florin is a typical example of what can be achieved with other crops. Taking these developments into considera­ tion, the present volume, Haploids in Crop Improvement I, was compil­ ed.