Using Biotech to Speed Classical
Breeding By Ben
Hardin September 12, 2001
Biotechnology, somewhat like the proverbial hare in its contest
with the tortoise, raced speedily to bring forth corn transformed with a
bacterial protein to resist insects. But now the new science is set to help
hasten traditionally slower classical plant breeding to develop
insect-resistant corn breeding lines, without the foreign genes.
For example, through 15 years of work, researchers developed
corn inbred line Mo47, which is renowned for its ability to resist both first
and second generations of the European corn borer. On U.S. farms, European corn
borers are responsible for annual damage and control costs exceeding $1
billion.
Recently, Agricultural
Research Service (ARS) scientists at Columbia, Mo., and their
University of Missouri
colleagues, in three years, used fast-paced biotechnological tools to find
locations of DNA sequences that confer borer resistance to Mo47. Soon corn
geneticists, in a process called marker-assisted selection, may use the
information to quickly develop improved insect-resistant corn from diverse
genetic resources.
Marker-assisted selection is a way of dealing with the fact that
typically, multiple genes govern a single trait of economic importance. These
genes locations are called quantitative trait loci (QTLs). In DNA
marker-assisted selection, researchers conduct DNA tests on corn breeding lines
to find out whether they have the most desired QTLs. Lines that do are used for
breeding.
ARS geneticist
Michael D.
McMullen and collegaues in Missouri found, on six chromosomes, nine QTLs
associated with Mo47's resistance to first-generation European corn borer leaf
feeding damage. The researchers also found seven QTLs for resistance to
second-generation borer stalk tunneling damage.
ARS is the chief scientific research agency of the
U.S. Department of Agriculture. The ARS
scientists are based at the
Plant Genetics
Research Unit. |