Thrive Under Typical U.S. Day Length
By Sharon Durham
May 24, 2002
New sorghums that flourish under day
length conditions typical in the Unites States could result from a large-scale
genetic screening program now being coordinated by
Agricultural Research Service scientists
Plant Genetic Resources Conservation Unit in Griffin, Ga., under the
direction of sorghum coordinator Gary Pederson, provided almost 25,000 sorghum
accessions to researchers who then evaluated them for a trait known as
photoperiod sensitivity. Photoperiod--the cycle of light and darkness a plant
receives--is tied to day length, which increases during the long days of the
U.S. growing season.
Certain sorghums dont grow well during these long days in the United
States. Only sorghum that is insensitive to day length will reach full maturity
and produce harvestable seed in this country.
The sorghum accessions tested were obtained from the ARS national
active collection of sorghum germplasm. In Texas, scientists grew
the plants and evaluated them for their photoperiod sensitivity. This was an
ARS collaboration with the Sorghum Crop Germplasm Committee,
National Grain Sorghum Producers,
and university and industry scientists.
In this cooperative study, scientists determined that 4,193 accessions
should be selected because they are less sensitive to day length. That quality
was then entered into the Germplasm Resources
Information Network for use by researchers worldwide. In spring 2001, seed
from these accessions was sent to cooperating private companies so that
additional seed could be produced from these plants.
This seed was then sent back to the Griffin lab for processing, cleaning,
and counting for distribution during spring 2002 to sorghum breeders and other
interested users. The seeds will be grown out at locations in Texas and Kansas
this summer for evaluation.
Distribution of seed allows plant breeders to incorporate new genetic
diversity into crops and provides growers with cultivars that have desirable
genetic traits for various growing conditions.
The national sorghum collection is evaluated and regenerated at Mayaguez,
Puerto Rico, and a base collection is maintained in long-term storage at Ft.
ARS is the chief scientific research agency of the
U.S. Department of Agriculture.