Preface

What is a weed? A plant whose virtues have not been discovered.

— Ralph Waldo Emerson (1803–1882)

Exotic germplasm, often known as weeds, are wild relatives of crops. These wild relatives may contain many undesirable qualities, but they may also harbor a few traits of economic importance that can be transferred to cultigens by conventional chromosome engineering, as well as by molecular methods. Major cereals, grain legumes, oilseeds, vegetables, and forage crops have been an integral part of human civilization since time immemorial. They were selected and domesticated from their wild progenitors. These crops are the primary food source for the world human and animal populations.

The majority of the oilseed crops originated in the Old World. Groundnut and sunflower originated in the New World. Today, groundnut and sunflower are important oil crops and are produced throughout the world. Vegetable oils are an excellent source of highly nutritional cooking oil for humans, and oil cake and meal products provide protein-rich meal for animals. Pharmaceutical industries use vegetable oils for producing cosmetics, medicines, and numerous oil-based products. Oil processing industries refine heart healthy oil as well as by-products. Various methods of oil extraction and purification and development of foods for human and animal use have been discovered, invented, and improved upon since humans identified oilseed crops and learned their use. The indigenous Indian method of oil extraction, known as ghani, is still practiced in the villages of India. Modern oil processing industries have constructed refineries worldwide. Processing industries extract oil from the meal and remove antinutritional elements during processing. Oilseed crops are one of the wonders of nature because they are used for human food (salad oil, margarine, Vanaspati , shortening, cooking, and bakery) and animal feed, as well as for other commercial applications (pharmaceutical products, soap, paints and resins, coatings, linoleum, cosmetics, lubrication, chemicals, plastic coatings, and ethanol). However, information on oil extraction, refinement, and production of meals for human, animal, and technical use is beyond the scope of this book.

Because of their healthful fatty acid composition, vegetable oils provide us heart-healthy polyunsaturated fatty acids that are free of hydrogenated trans fatty acids. However, vegetable oils turn unhealthy when reheated at high temperatures, as they release a toxin called 4-hydroxy-trans- 2-nonenal (HNE). Numerous studies link HNE consumption to increased risks for cardiovascular disease, stroke, Parkinson's, Alzheimer's, and Huntington's diseases, liver ailments, and even cancer (<http://www.medicinenet.com/script/main/art.asp?articlekey=47063>).

Sunflower oil is not commonly used for industrial purposes because of its generally higher value, compared to other oilseeds. However, it is used to some extent in some paints, varnishes, and plastics. It imparts desirable semidrying properties, without the yellowing problems associated with oils high in linolenic acid. Sunflower oil is also used in the manufacture of soaps and detergents. Vegetable oils have potential value for the production of adhesives, agrichemicals, surfactants, plastics and plastic additives, fabric softeners, synthetic lubricants, and coatings. Actual use depends, to a large extent, on its price, relative to that of petroleum and petro-based chemicals. The prices of oilseeds and their products depend on the supply of oilseeds, and the market is supply oriented.

Some oilseed crops (soybean, groundnut, sunflower, sesame) may be consumed raw or cooked as food. Non-oilseed or confectionery sunflower seeds usually have very large, black with whitestriped achenes and are used as a confection or snack food, roasted and salted. Sunflower kernels are also used in the baking industry, as a condiment for salads, and other foods. Non-dehulled or partially dehulled sunflower meal can be substituted successfully for soybean meal of equal protein percentage in feeding ruminant animals. Achenes are also used for feeding birds and in small animal feed. Sesame has been primarily an oil crop, but the seeds are also used in baked goods, for condiments, and in making sweets such as halva and candy bars, and in fast foods.

Soybean accounts for 53% of all the oilseed crops (excluding perennial tree crops) production listed by the Food and Agriculture Organization (FAO) (<http://faostat.fao.org>). Thus, soybean plays a dominant role in the international trade, foreign exchange earnings, and oil processing because it is rich in protein (40%) and oil (20%). Rapeseed contains 36 to 50% oil (on a dry matter basis), while the oil-free meal contains 33 to 48% protein. Soybean, although originating in China, is produced mainly by the U.S., Brazil, and Argentina. Soybean is considered a miracle crop of the Orient because in addition to oil and protein, the root nodules of soybean contain rhizobial bacteria, which play a positive role in crop rotations with cereals and help replenish soil's nitrogen supply. It has been used for generations in India, especially in the hills, as both animal and human feed.

The intensive varietal improvement of oilseed crops for high yield and improved nutritional quality (elimination of antinutritional quality) are the primary breeding objectives of various national (public institutions and private industries) and international programs. The groundnut varietal improvement program is among those mandated by the International Crops Research Institute for the Semiarid Tropics (ICRISAT), Patancheru, India. The Asian Vegetable Research and Development Center (AVRDC), Shanhua, Taiwan, breeds edible vegetable soybean known as edamame. The International Soybean Program (INTSOY), established in 1973, at the University of Illinois at Urbana-Champaign, promotes soybean products worldwide and is an international soybean resource. However, it does not have a soybean varietal improvement program.

Most genetic improvement of oilseed crops has been accomplished by conventional breeding assisted by germplasm resources, cytogenetics, plant pathology, entomology, agronomy, cell and tissue cultures, and molecular biology. A major technological breakthrough by genetic engineering was the creation of Roundup Ready^® soybean and rapeseed (widely known as canola). Roundup Ready soybean is widely grown in the U.S. and rapeseed in Canada. Production of both crops is expanding in other countries of the world.

Three books on oilseed crops are in print: Salunkhe and Desai (1986) published a book on postharvest biotechnology of oilseeds (CRC Press); Röbbelen, Downey, and Ashri (1989) edited Oil Crops of the World (McGraw-Hill); and Weiss (2000) revised (second edition) his book on oilseed crops. With the exception of soybean and rapeseed, however, there are no consolidated accounts of germplasm resources, cytogenetic manipulations, biotechnological approaches, and breeding of the remaining oilseed crops. Volume 4 in the Genetic Resources, Chromosome Engineering, and Crop Improvement series provides a comprehensive, consolidated resource for seven oilseed crops. Worldrenowned scientists contributed chapters on the vegetable oilseed crops of their expertise.

Chapter 1 summarizes the landmark research done in the seven oilseed crops discussed in this book. Each chapter provides a comprehensive account of the origin of the crop, its genetic resources in various gene pools, basic and molecular cytogenetics, conventional breeding, and the modern tools of molecular genetics and biotechnology. Appropriate germplasm collections can be an excellent source for genetic enhancement of various traits in oilseed crops and for broadening their genetic base. The genetic base of oilseed crops is extremely narrow. In view of this, three gene pools have now been identified by scientists: primary (GP-1), secondary (GP-2), and tertiary (GP-3) for each crop. The recommendation is to use GP-2 and GP-3 resources in producing widely adapted varieties. Utilization of these resources in producing high-yielding cultivars, resistant to abiotic and biotic stresses, and with improved nutritional qualities, is discussed in this book.

Seven major oilseed crops, such as soybean (Chapter 2), groundnut (Chapter 3), cottonseed (Chapter 4), sunflower (Chapter 5), safflower (Chapter 6), Brassica oilseeds (Chapter 7), and sesame (Chapter 8), are included in this book. Linseed has been excluded from this volume (per Allan Green, personal communication). Perennial tree crops like coconut, babassu nut, oil palms, and jojoba are also not included.

Each chapter has been written by one or more experts in the field. I am extremely grateful to all the authors for their outstanding contributions, and to the reviewers of all the chapters. I have been fortunate to know them both professionally and personally, and our communication has been very cordial and friendly. I am particularly indebted to Thomas G. Isleib, Govindjee, and Joseph Nicholas for their comments and suggestions on some of the chapters. Finally, I thank Steven G. Pueppke, former associate dean and research director at the University of Illinois, Urbana, for his support and encouragement.

This book is intended for scientists, professionals, and graduate students whose interests center upon genetic improvement of crops in general and major oilseed crops in particular. This book is intended as a reference for plant breeders, taxonomists, cytogeneticists, germplasm explorers, pathologists, entomologists, physiologists, agronomists, molecular biologists, food technologists, and biotechnologists. Graduate students in these disciplines, with an adequate background in genetics, as well as other researchers interested in biology and agriculture will also find this volume a worthwhile source of reference. I sincerely hope that the information assembled will help in the much needed genetic amelioration of oilseed crops to feed the ever-expanding global population. I anticipate that this book will enhance awareness regarding nutritive values of oilseeds, preventing malnutrition worldwide.