Barley for Food and Health: Science, Technology, and Products

42 BARLEY BIOTECHNOLOGY: BREEDING AND TRANSGENICS
from any organism: from barley itself to other cereals or plants, bacteria, and
even humans. Why transgenic barley? Classical or traditional plant breeding can
do just so much with currently available alleles in compatible germplasm in terms
of continued improvements in barley crop yields, while enhancing malt quality
and nutritional value for food and feed. The application of genetic engineering to
cereal grain breeding has the potential to expedite the solution to many problems
facing the agricultural and food industries, such as conserving natural resources
and protecting the environment while providing abundant economical products
to the consumer. Considering the current worldwide population explosion, it is
imperative that genetic engineering of barley and other cereals be promoted and
extended. Collectively, cereal grains account for 66% of the world food supply
(Borlaug 1998), and according to Vasil (1999), food production must be doubled
from the turn of the century to 2025 and nearly tripled by 2050 to meet the food
needs of the twenty-first century. It is doubtful that such increases in world food
production can be accomplished in such a short period of time by traditional
breeding alone. For example, the development of a new and improved variety
of a cereal grain may take 10 or more years using traditional breeding practices.
Today, that time span can be reduced significantly by using the best available
tools. Careful selection and introduction of desirable genes from other plants or
organisms into the barley genome provides the necessary avenue for continued
improvement of this important crop.
Yield is the single most important criterion for a cereal crop, including barley,
but yield in itself is not due to a single attribute. Improved yield is controlled by
many factors, resulting from improved crop management strategies in addition to
plant selection for superior genotypes that are resistant to diseases, pests, lodging,
shattering, drought stress, and other environmental hazards. Enhancing these
traits in barley is within the reach and abilities of scientists trained in the science
and techniques of genetic engineering and breeding. In addition to producing better
barley plants, genetic engineering provides a new way to produce nutritionally
improved foods for areas of the world where barley is a mainstay for food and
feed. Genetic engineering can be used to create specially designed barley foods to
provide for the dietary needs of individuals susceptible to food allergies or who
suffer from diabetes, cardiovascular disease, or other food-related illnesses (see
Chapter 8). Specially designed hulless barleys, which provide high-protein nutritionally
enhanced feedstocks, can be engineered to increase biofuel production.
Through genetic engineering, there is the potential, safely and economically, to
produce many useful compounds, such as enzymes, antibiotics, hormones, and
other biological agents, utilizing completely environmentally friendly methods.
Delivery Systems
Methods of transforming plant cells may be classed as either indirect or direct.
Indirect transformation involves the use of a soil phytopathogen, Agrobacterium
tumefaciens, that induces tumors known as crown galls, primarily on dicotyledonous
plants. There are several known strains of agrobacteria; however,