Source: Coy, Ruth, and Dennis Senft. 1990.
In search of perfect plants.
Agric. Res. 38(10):4-10.
In a world of
ever increasing population, many are asking if there will be enough food for
the future? Governments and farmers have turned towards science in hopes of a
favorable answer. The best answer may come from plant breeding. Newer and
stronger plants that have the potential to increase yields are being produced. Ruth
Coy and Dennis Senft have documented where the science of plant breeding
started, where it is now, and where its heading. Scientists, in an attempt to
breed plant species with desirable traits, have taken advantage of a modified
form of natural selection. With natural selection only adapted plants survive
and better adapted individuals have a higher chance of survival. These
survivors then go on to reproduce, in turn creating a new generation of
genetically superior plants. The corresponding process used by plant breeders
is relatively simple; scientists will plant about 100,000 seedlings of a given
crop. The crop grows to maturity and about 10,000 plants are selected for the
presence of a desirable trait. These 10,000 are then grown, and out of these
about 1,000 selected individuals are planted in the field for the following year.
Out of these 1,000, approximately 100 are then chosen for cloning and planted
at several locations. This generation is grown in about four different
locations to determine adaptability to different environments. Finally 8 to 11
of these clones are selected for detailed testing with 2 to 4 years of
evaluation. Upon meeting all criteria for the desired trait the new variety of
the crop is then introduced to the commercial market. On average it takes 12 to
15 years to breed a genetically superior crop. There are at least 50
controllable traits for yield, cold hardiness, drought tolerance, shape, color,
flavor, and nutrients, so it takes a long time to get all the desired traits
together. ARS scientists have bred citrus that resist cold, soybeans with higher
nutritional values, and cotton that is mildly resistant to insects. As
traditional plant breeding has reached its potential, new methods called
genetic engineering are taking over. The possibilities for genetic engineering
of crops is almost boundless. "Gene transfer techniques may one day be
used to introduce desirable characteristics into a species from a wholly
unrelated species," say the authors. The science of crop breeding has come
a long way and there is still much to learn.
Abstract author: David Whitehead, 21
November 1995.
SUSAG Abstracts: Go back to the
SUSAG Abstracts search page.