A range of techniques is available to the plant breeder today to complement classical breeding methods. The options are based on the integration of advances in plant cell biology with those in plant molecular biology. Plant cell, tissue and organ cultures provide efficient systems for transformation, for the achievement of wide crosses and for the production of variation through spontaneous and induced mutation, while permitting effective isolation of desired genotypes by in vitro selection. This volume presents a critical appraisal of the methodologies of plant genetic manipulation for advanced undergraduates, postgraduates, researchers and plant breeders, and provides guidance on the choice of breeding options. The latter depends on the breeding system of the crop, the breeding objective and the tissue culture systems applicable to the target genotype(s).

Advan ces in production technology.- System analysis of yield trials can raise efficiency of breeding for yield.- Research needs in the production of high quality seeds.- Breeding for quality and resistance to fusarial wilt in gladiolus.- Reproductive biology of potato: Basis for true seed production.- Resistance breeding under coordinated programme.- Quality improvement of Punjab grapes.- Exploitation of allien genes for yellow vein mosaic resistance in okra.- Use of vesicular-arbuscular mycorrhiza (VAM) as biofertilizer for horticultural plants in developing countries.- Foliar feeding of zinc and iron in peach.- Conservation of wild plants of horticultural importance from Tumkur district, Karnataka.- Potential of seed storage at ambient temperature using organic liquids to avoid refrigeration.- Chemical weeding as a labour saving device in management of fruit nurseries.- Role of germplasm in Citrus rootstock improvement.- Comparative efficacy of single and split applied nitrogen on yield and quality of 'Perlette' grapes.- Induced mutations recovered in M2 and subsequent generations in three varieties of okra (Abelmoschus esculentus (L.) Moench).- Plant genetic manipulation.- Role of viruses in plant biotechnology.- Microbial populations, host-specific virulence & plant resistance genes.- Genetically engineered resistance in plants against viral infection.- Genetic engineering and transformation of monocots for crop improvement.- Agrobacterium-mediated gene transfer in Citrus reticulata Blanco.- Regeneration and genetic transformation studies in watermelon (Citrullus vulgaris L. cv. Melitopolski).- Molecular aspects of cytokinin's stymied action on auxin-mediated new root formation in the hypocotyls of Phaseolus vulgaris L..- Plant cell and tissue culture.- Commercial aspects of micropropagation.- Large scale micropropagation: it's strategic use in horticulture.- Micropropagation of bulb crops.- Current status of forest biotechnology.- Large scale secondary metabolite production: the sanguinarine story.- Current research on micropropagation of Sulcorebutia alba Rausch, Syringa vulgaris L., Hip-peastrum hybrids and Tulipa hybrids.- Plant cell culture and food biotechnology: current trends and future prospects.- Tissue culture propagation: problems and potentials.- Micropropagation and plant conformity in Anthurium andreanum.- Rapid in vitro propagation of virus-indexed Freesia.- Effect of culture media and growth regulators on in vitro propagation of rose.- Shoot tip culture method for rapid clonal propagation of pomegranate (Punica granatum L.).- Tissue culture strategies for banana.- Gynogenic plants from ovary cultures of Mulberry (Morus indica).- Induction of high frequency somatic embryogenesis and plant regeneration in mandarins.- Tissue culture of medicinal plants: morphogenesis, direct regeneration and somatic embryogenesis.- Production of important phytochemicals through plant cell cultures and scale-up operations: limitations and prospects.- Establishment of somatic cell culture and plant regeneration in grapes (Vitis vinifera L.).- In-ovulo embryo culture in seedless grapes (Vitis vinifera L.).- Micropropagation of Davana (Artemisia pallens Wall.) by tissue culture.- Clonal propagation of bamboo, coffee and mimosa.- Greenhouse technology.- Greenhouse environmental control for Indian conditions.- New seed-grown cut flowers for floriculture industry.- Cut flowers in the Western Hemisphere.- Decision support for integrated greenhouse production systems.- Greenhouse pot plant production in the United States.- Robotics applications to transplanting of plug seedlings.- Plant health and crop protection.- Immunological and molecular approaches to the diagnosis of viruses infecting horticultural crops.- Viruses of ornamentals - identification and diagnosis.- Protein-A supplemented immune electron microscopy for diagnosis of potato viruses X, S, Y and leafroll.- Production of virus-tested seed potatoes.- Pesticide deconta

The book centres around an analysis of the options for the agronomic development of semiarid regions with winter rains (i.e. Mediterranean regions). Data obtained in the northern Negev desert in Israel served as a starting point. On the basis of these data crop and sheep husbandry systems were designed and integrated into agro-pastoral systems in which small-grain crops act as a buffer for feed production. These systems serves as a basis for rational planning of regional agricultural development under alternative development objectives. In analyzing the possibilities a three-step approach was developed: first the feasibility and robustness of selected innovative techniques at the farm level were investigated in relation to variability in weather and prices, then a matrix of production techniques for a region was formulated in terms of their physical imputs and outputs, and finally this matrix was embedded into a dynamic multiple-goal linear programming model. In comparing results for different goals, the consequencess for goal achievement and desired production techniques can be made explicit, and in this way the book can be a guide for actual development planning in semiarid regions.

At present, plants and agricultural sciences are playing a leading role in providing solutions to problems created by an ever growing world population. Through plant biotechnology scientists are seeking ways to improve crop functions that rapidly promote food production. Agricultural science is being used to experiment with producing plants tolerant to environmental stresses such as drought, salinity and coldness.

Of the plant species, woody plants are producing the most abundant biomass resources, playing important roles in the suppression of carbon dioxide increase and supplying huge energy and resources to human beings in the biosphere.
These Proceedings discuss the recent results of fundamental and applied research for global resource and energy, biomass production and environmental problems from the aspect of woody science.

Topics include:
- Formation of the vascular bundle
- Biosynthesis of cellulose
- Lignin biosynthesis and transgenic woody plants
- Cell and tissue culture, and transformation in gymnosperms
- Micropropagation of woody plants

Petunia belongs to the family of the Solanaceae and is closely related to important crop species such as tomato, potato, eggplant, pepper and tobacco. With around 35 species described it is one of the smaller genera and among those there are two groups of species that make up the majority of them: the purple flowered P.integrifolia group and the white flowered P.axillaris group. It is assumed that interspecific hybrids between members of these two groups have laid the foundation for the huge variation in cultivars as selected from the 1830 s onwards.

Petunia thus has been a commercially important ornamental since the early days of horticulture. Despite that, Petunia was in use as a research model only parsimoniously until the late fifties of the last century. By then seed companies started to fund academic research, initially with the main aim to develop new color varieties. Besides a moment of glory around 1980 (being elected a promising model system, just prior to the Arabidopsis boom), Petunia has long been a system in the shadow. Up to the early eighties no more then five groups developed classical and biochemical genetics, almost exclusively on flower color genes. Then from the early eighties onward, interest has slowly been growing and nowadays some 20-25 academic groups around the world are using Petunia as their main model system for a variety of research purposes, while a number of smaller and larger companies are developing further new varieties.

At present the system is gaining credibility for a number of reasons, a very important one being that it is now generally realized that only comparative biology will reveal the real roots of evolutionary development of processes like pollination syndromes, floral development, scent emission, seed survival strategies and the like.

As a system to work with, Petunia combines advantages from several other model species: it is easy to grow, sets abundant seeds, while self- and cross pollination is easy; its lifecycle is four months from seed to seed; plants can be grown very densely, in 1 cm2 plugs and can be rescued easily upon flowering, which makes even huge selection plots easy to handle. Its flowers (and indeed leaves) are relatively large and thus obtaining biochemical samples is no problem. Moreover, transformation and regeneration from leaf disc or protoplast are long established and easy-to-perform procedures. On top of this easiness in culture, Petunia harbors an endogenous, very active transposable element system, which is being used to great advantage in both forward and reverse genetics screens.

The virtues of Petunia as a model system have only partly been highlighted. In a first monograph, edited by K. Sink and published in 1984, the emphasis was mainly on taxonomy, morphology, classical and biochemical genetics, cytogenetics, physiology and a number of topical subjects. At that time, little molecular data was available. Taking into account that that first monograph will be offered electronically as a supplement in this upcoming edition, we would like to put the overall emphasis for the second edition on molecular developments and on comparative issues.

To this end we propose the underneath set up, where chapters will be brief and topical. Each chapter will present the historical setting of its subject, the comparison with other systems (if available) and the unique progress as made in Petunia. We expect that the second edition of the Petunia monograph will draw a broad readership both in academia and industry and hope that it will contribute to a further expansion in research on this wonderful Solanaceae."

The perception that civilization is crossing a period of Global Climatic Changes that can seriously threaten our lifestyle, along with energy security and the search for prosperity, are the main drivers that are pushing men to use more biomass as a source of energy. It will be crucial that such intent will include a large parcel of sustainability so that more renewable energy becomes available for populations. Because large amounts of energy are "hidden" in carbon polymers made by plants, notably carbohydrates, it is obvious that if technologies are developed to produce liquid fuels such as ethanol from carbohydrate polymers such as cellulose, men could significantly increase energy sustainability . This book reviews general aspects of biomass utilization for bioenergy production as well as strategies using biochemistry, molecular biology, chemistry and physics to disassemble plant cell walls. Recent discoveries of basic science under development in several laboratories in the world are reviewed by experts that have been intensively working with many aspects that will impact the development of the technology of production of cellulosic ethanol.

It is important to include Tuber and Root Crops in the Handbook of Plant Breeding. They include starchy staple crops that are of increasing importance for global food security and relief of poverty, important millennium goals for the United Nations. Indeed, 2008 was the UN International Year of the Potato in recognition of this role of the potato as the world s third most important food crop after wheat and rice. The other major staples are cassava, sweetpotato and yam. Together they occupy about 50 million hectares, with production at 640 million metric tons, of which 70% is in developing countries. In total there are more than 30 species of Root and Tuber Crops grown in the world today. Given the content of other volumes in the series, it makes sense to include sugar and fodder beets; swedes and turnips; and minor root and tuber crops so that the book series is as complete as possible. Like the other volumes in the series, this one will present information on the latest in applied plant breeding using the current advances in the field, from an efficient use of genetic resources to the impact of biotechnology in plant breeding. Seven crop specific chapters are proposed, together with an introduction to this diverse set of plant species. Outstanding scientists for each crop species are proposed as senior authors, who may invite co-authors to contribute part of a chapter. In order to increase the overall acceptance of the volume, balance will be sought with authors from different research groups/countries who will be asked to contribute and collaborate where appropriate. The book should be of interest to researchers in both academic and industrial settings, and in both developed and developing countries, as well as students and teachers of plant breeding. It is currently extremely important to educate and train a new generation of plant breeders given the challenges faced by humankind in producing more food for an expanding global population during a period of environmental (including climate) change."

This book - the first published on this topic in plants - presents the reader with an overview of recent research on nitric oxide (NO) in plants, which, in view of its empirical interest and its growth regulatory potential, is in the forefront of scientific endeavor in plant science. Subject matter is divided into two parts: Part 1 deals with NO and peroxynitrite biochemistry and regulative mechanisms as presently known in the Plant Kingdom and outlines some of the problems still awaiting clarification. Emphasis is placed on ethylene emission regulation, postharvest control, plant phytopathology and environmental stress tolerance. A further topic is plant NO, like Viagra, related to cyclic nucleotide turnover. Part 2 deals with environmental aspects of NO as an atmospheric pollutant and discusses endogenous means which plants at times employ to cope with this particular type of stress, and how their coping mechanisms may be harnessed for purposes of depollution and augmentation of nitrogen fertilization. The text, accompanied by a wealth of illustrations and annotated references, is intended for lecturers, advanced students and research scientists at universities and research institutes dealing with plant sciences and agriculture, as well as for environmental researchers.

Forage plant breeding has entered the genome era. This timely book reviews the latest advances in the development and application of molecular technologies which supplement conventional breeding efforts for our major forage crops. It describes the plethora of new technologies and tools now available for high-throughput gene discovery, genome-wide gene expression analysis, production of transgenic plants, genome analysis and marker-assisted selection as applied to forage plants. Detailed accounts are presented of current and future opportunities for innovative applications of these molecular tools and technologies in the identification, functional characterisation, and use of valuable genes in forage production systems and beyond. This book represents a valuable resource for plant breeders, geneticists, and molecular biologists, and will be of particular relevance to advanced undergraduates, postgraduates, and researchers with an interest in forage legumes and grasses.

This volume contains comprehensive reviews on the current status of knowledge concerning the physiological, biochemical, and molecular events underlying plant morphogenesis processes authored by the main lecturers at the NATO Advanced Study Institute which was held in Heraklion, Crete, Greece, Septe

Red clover (Trifolium pratenseL. ) is an important forage of most ofthe tem- perate regions of the world, and atone time was the most importantlegume for hay in the United States. Oddly enough,red clover has never been the subject ofa monograph, although its culture has been discussed in many monograph chapters in the United States and Europe, perhaps beginning with those of Westgate and Hillman ina USDAFarmers Bulletin in 1911and early Swedish publications. The monograph "CloverScience and Technology" published in 1985 provides coverage of red clover along with other Trifolium species. It was theobjective of thepresentmonograph, "Red Clover Science" toexamine the literature published on red clover primarily after 1984. Perhaps the tim- ing of this publication is appropriate with the present interest in sustainable agriculture ofwhich red clover was so prominent in the past. Red clover and other forage legumes are valuable for reducing our reliance on fossil fuels, and for reducing pollution of our soil, water, and atmosphere primarily from use of chemical nitrogen and other fertilizers. In each chapter, an attempt was made to summarize the earlierinformation and to integrate the recent findings into this background. References earlier than 1984 are included only when necessary for historical purposes. No attempt was made to review the many aspects of clover culture that has been described thoroughly in earlier pub- lications. The literature covered is necessarily worldwide becauseofpresent greater emphasis in northern Eurasia than in United States.

Our requirement for plant breeders to be successful has never been greater. However one views the forecasted numbers for future population growth we will need, in the immediate future, to be feeding, clothing and housing many more people than we do, inadequately, at present. Plant breeding represents the most valuable strategy in increasing our productivity in a way that is sustainable and environmentally sensitive. Plant breeding can rightly be considered as one of the oldest multidisciplinary subjects that is known to humans. It was practised by people who first started to carry out a settled form of agriculture. The art, as it must have been at that stage, was applied without any formal underlying framework, but achieved dramatic results, as witnessed by the forms of cultivated plants we have today. We are now learning how to apply successfully the results of yet imperfect scientific knowledge. This knowledge is, however, rapidly developing, particularly in areas of tissue culture, biotechnology and molecular biology. Plant breeding's inherent multifaceted nature means that alongside obvious subject areas like genetics we also need to consider areas such as: statistics, physiology, plant pathology, entomology, biochemistry, weed science, quality, seed characteristics, repro ductive biology, trial design, selection and computing. It therefore seems apparent that modern plant breeders need to have a grasp of wide range of scientific knowledge and expertise if they are successfully to a exploit the techniques, protocols and strategies which are open to them.

Plant hormones play a crucial role in controlling the way in which plants growand develop. Whilemetabolism providesthepowerand buildingblocks for plant life, it is the hormones that regulate the speed of growth of the individual parts and integrate these parts to produce the form that we recognize as a plant. In addition, theyplayacontrolling role inthe processes of reproduction. This book is a description ofthese natural chemicals: how they are synthesizedand metabolized; howthey work; whatwe knowoftheir molecular biology; how we measure them; and a description ofsome ofthe roles they play in regulating plant growth and development. Emphasis has also been placed on the new findings on plant hormones deriving from the expanding use ofmolecular biology as a tool to understand these fascinating regulatory molecules. Even at the present time, when the role of genes in regulating all aspects of growth and development is considered of prime importance, it is still clear that the path of development is nonetheless very much under hormonal control, either via changes in hormone levels in response to changes in gene transcription, or with the hormones themselves as regulators ofgene transcription. This is not a conference proceedings, but a selected collection ofnewly written, integrated, illustrated reviews describing our knowledge of plant hormones, and the experimental work that is the foundation of this knowledge.

Since the beginning of agricultural production, there has been a continuous effort to grow more and better quality food to feed ever increasing popula tions. Both improved cultural practices and improved crop plants have al lowed us to divert more human resources to non-agricultural activities while still increasing agricultural production. Malthusian population predictions continue to alarm agricultural researchers, especially plant breeders, to seek new technologies that will continue to allow us to produce more and better food by fewer people on less land. Both improvement of existing cultivars and development of new high-yielding cultivars are common goals for breeders of all crops. In vitro haploid production is among the new technologies that show great promise toward the goal of increasing crop yields by making similar germplasm available for many crops that was used to implement one of the greatest plant breeding success stories of this century, i. e., the development of hybrid maize by crosses of inbred lines. One of the main applications of anther culture has been to produce diploid homozygous pure lines in a single generation, thus saving many generations of backcrossing to reach homozygosity by traditional means or in crops where self-pollination is not possible. Because doubled haploids are equivalent to inbred lines, their value has been appreciated by plant breeders for decades. The search for natural haploids and methods to induce them has been ongoing since the beginning of the 20th century."

For all undergraduate courses in plant propagation at the two-year and four-year colleges and universities. The world standard for plant propagation and horticulture for over 50 years, Hartmann and Kester's Plant Propagation continues to be the field's most complete, up-to-date text on plant propagation. It now contains color figures throughout, promoting learning and making it an even more useful working text and reference. It also contains extensive updates reflecting the latest commercial techniques and understanding of propagation biology. Like previous editions, it is organized into paired chapters on principles and practices, so it can easily be adapted for teaching courses that cover only practical topics, and for courses that also cover conceptual issues.

Topics for the Beltsville Symposia are selected to highlight specific areas of research and science policy that are of concern to scientists in the Beltsville Area as well as to the general scientific community. Each sympo sium in the series is structured to provide a realistic appraisal of current findings, research progress, and relevant policy issues within the constraints established by the organizing committee. Thus, the presentations and dis cussions that have marked these symposia have had a strong appeal to the broad community of scientists. Knowledge of the diversity of living organisms is still quite limited. Since the time of Linnaeus, about 1.7 million species have been described. The actual number has been estimated between 5-50 million. Many species, land races, and strains are vanishing. Clearly, the world's scientific institutions are inadequately equipped to attain sufficient knowledge of a significant fraction of the diverse living forms. Also, efforts in the collection and preservation of germplasm of plants and animals urgently need to be strengthened. These mattes are critically important to future generations. This symposium addresses vital concerns of biotic diversity and germ plasm preservation from diverse perspectives. Many of the parts provide concrete recommendations for action, and they call attention to areas of research that must be pursued with intensity."

The International Symposium on "Cellular and Molecular Aspects of Biosynthesis and Action of the Plant Hormone Ethylenc" ,vas held in Agen, France from August 31 st and September 4th, 1992. The planning and management of the scientific and social programme of the Conference were carried out jointly by the "Ethylene Research Group" of ENSAlIN"P (Toulouse) and Agropole Congres Service (Agen). Since the last meetings in Israel (1984) and in Belgium (1988), ethylene physiology has gone through a period of exciting progress due to new developments in cellular and molecular bioiogy. New methods and tools have been developed to better understand the role and functions of ethylene in fruit ripening, flower senescence, abscission, piant growth, and cell differentiation. Genes involved in ethylene biosynthesis have been characterized and transgenic plants with altered ethylene production have been generated. The feasibility of delaying fruit ripening or flower senescence by genetic manipulation is now demonstrated, thus opening new perspectives for the postharvest handling of plant products. Some progress has also been made on the understanding of ethylene action. However, much remains to be done in this area to elucidate the ethylene signal transduction pathway. Around 140 scientists from 20 countries attended the Symposium. They presented 47 oral reports and 40 poster demonstrations. All of them are published in these proceedings. It has been a pleasure for us to organize this important Symposium and to edit this book.

The quality of human life has been maintained and enhanced for generations by the use of trees and their products. In recent years, ever rising human population growth has put a tremendous pressure on trees and tree products; growing awareness of the potential of previously unexploited tree resources; and environmental pollution have both accelerated the development of new technologies for tree propagation, breeding and improvement. Biotechnology of trees may be the answer to solve the problems which can not be solved by conventional breeding methods. The combination of biotechnology and conventional methods such as plant propagation and breeding could become a novel approach to improving and multiplying a large number of the trees and woody plants. So far, plant tissue culture technology has largely been exploited by commercial companies in propagation of ornamentals, especially foliage house plants. Generally, tissue culture of woody plants has been recalcitrant. However, limited success has been achieved in tissue culture of angiosperm and gymnosperm woody plants. A number of recent reports on somatic embryogenesis in woody plants such as Norway spruce (Picea abies), Loblolly pine (Pinus taeda), Sandalwood (Santalum album), Citrus and mango (Mangifera indica), offer a ray of hope for inexpensive clonal propagation for large-scale production of plants or 'emblings' or somatic seedlings; protoplast work; cryopreservation; genetic transformation; and synthetic or artificial or manufactured seed production.

Proceedings of the EEC Flax Workshop, held in Brussels, Belgium, May 4-5, 1988 sponsored by the Commission of the European Communities, Directorate-General for Agriculture.

The International Centre for Advanced Mediterranean Agronomic Studies (CIHEAM), established in 1962, is an intergovernmental organization of four teen countries: Albania, Algeria, Egypt, France, Greece, Italy, Lebanon, Malta, Morocco, Portugal, Spain, Tunisia, Turkey and Yugoslavia. Four institutes (Bari, Italy; Chania, Greece; Montpellier, France and Zaragoza, Spain) provide post-graduate education at the Master of Science level. CIHEAM promotes research networks on Mediterranean agricultural priorities, supports the organization of specialized education in member countries, holds seminars and workshops bringing together technologists and scientists involved in Mediterranean agriculture and regularly produces diverse publications including the series 'Options Mediterraneennes'. Through these activities, CIHEAM promotes North/South dialogue and international co-operation for agricultural development in the Mediterranean region. Plant breeding is, since 1982, one of the fields in which CIHEAM is con ducting a programme of training and promotion of research, through its Mediterranean Agronomic Institute of Zaragoza. The programme includes a one-year advanced specialization course, a series of two-week courses for professionals, and support for collaborative research activities in Mediterranean-relevant species. Many of these activities are organized in col laboration with national and international institutions. The publication in 1993 of Plant Breeding. Principles and Prospects, which ini tiated the Chapman & Hall's Plant Breeding Series, has become an important feature of CIHEAM's plant breeding programme. We are now pleased to add a further volume to that series: the present book, Statistical Methods for Plant Variety Evaluation."

The beginnings of human civili zation can be traced back to the time , ne- ly 12 ,000 years ago , when th e early humans gradually ch anged from a life of hunting and gathering food , to producing food. This beginning of pri- tive agriculture ensured a dependable supply of food , and fostered the living together of people in groups and the development of s o c i e ty. During th is time, plant s e e ds were recognized a s a valuable s o ur c e of food and nutrition , and began to be used for growing plants for food. Ever s i n c e , plant seeds have played an important role in the development of the human civilization . Even today, s e e ds of a few crop s p e c i e s , s uc h as the cereals and legume s, are the primary s o u r c e of most human food , and the predominant commodity in international agriculture. Owing to their great importance as food for human s and in international trade , seeds have been a favorite object of s t u d y by developmental biologists and physiologi sts , nutritionist s and chem i sts . A wealth of useful information i s available on th e biology of seed s .

This book contains papers and posters presented at the 18th Eucarpia Fodder Crops Section Meeting held at Loen, Nordfjord, Norway in August 1993. In most environments some form of marginal conditions or stress prevails. Few crops are being produced under such a wide range of environmental and management stresses as fodder crops. Improved adaptation of fodder crops to marginal conditions is crucial in developing sustainable, low-input agricultural systems. The book is unique in demonstrating the large diversity both in crops and environmental stresses that confront the forage breeders. Both general and specific aspects of adaptation to marginal growing conditions are presented, ranging from problems caused by snow and ice in the Subarctic regions of Europe to the severe drought problems in the Mediterranean regions. For everyone involved in studies of adaptation and breeding of perennial plants for marginal conditions or stress environments.

The inflorescence of the monoecious maize plant is unique among the Gramineae in the sharp separation of the male and female structures. The male tassel at the terminus of the plant most often sheds pollen before the visual appearance of the receptive silks of th the female ear at a lateral bud, normally at the 10 leaf [I]. Earlier studies examined the ontogeny of the growing tissues beginning with the embryo in the kernel through to the obvious protuberances of the growing point as the kernel germinates. The differentiated developing soon-to-become tassel and the lateral bulges that develop into the ears on the lateral buds become apparent very early in the germinating kernel [2, 3, 46]. A certain number of cells are destined for tassel and ear development [8]. As the plant develops, there is a phase transition [\3, 16] from the vegetative lateral buds to the reproductive lateral buds. This change in phase has been ascribed to genotypic control as evidenced in the differences among different genotypes in the initiation of the reproductive [I]. The genetic control of tassel and ear initiation has been gleaned from anatomical observations. Lejeune and Bernier [I2] found that maize plants terminate the initiation of additional axillary meristems at the time of tassel initiation. This would indicate that the top-most ear shoot is initiated on the same day as the initiation of tassel development and this event signals the end of the undifferentiated growing point.