World Grain - March 2015 - 38

FEATURE: IMPROVING SORGHUM

cropping strategies, they could grow sorghum in areas where the growing season
was previously considered too short.
Cool evening temperatures in the
spring and cold temperatures in the
early fall make the growing season in
northeastern Colorado too short to raise
the sorghum varieties grown in southern Colorado. Northeastern farmers
plant corn rather than sorghum, often
rotating it with winter wheat. But irrigation is rare in the region, and sorghum
would be a good option since it is more
drought-tolerant and less expensive to
produce than corn.
producing sorghum, Vigil and his colleagues at Colorado State University
studied several factors known to affect
plant maturity, including seeding density, hybrid selection, row spacing and
row orientation (a north-south or eastwest orientation).
Researchers grew two early-maturing
sorghum varieties and one "mediumearly" maturing variety in test plots. The
three sites are up to 200 miles apart and
represent a range of environments. They
planted in the spring and harvested in
late fall for two years. Based on planting
dates and temperature data, they determined the number of growing degreedays (GDDs) needed for plants to reach
maturity at each site. They also used historical weather data to calculate probabilities that the sites would experience the
required number of GDDs in a growing
season for plants to reach maturity.
The research showed that an earlymaturing hybrid had the best results.
Yields reached acceptable levels at all
three sites, but weather data showed suflikely in the most northern and most elshould be seeded at a rate of about 11
seeds per square meter (the mid-range
of the three seeding rates evaluated).
Row orientation and row spacing had
inconsistent effects on maturity rates.
In other sorghum studies, molecular
biologist Zhanguo Xin, plant geneticist
Gloria Burow, and lab director John
38

Burke, at the ARS Cropping Systems
Research Laboratory in Lubbock, Texas,
U.S., have bred a mutant sorghum plant
that produces 30% to 40% more seeds.
The researchers developed the higher
yielding sorghum by taking advantage of
a plant part called a spikelet, which is a
is a characteristic of other grasses, such
as millet or rye. Sorghum produces two
types of spikelets: the sessile spikelets
and the pedicellate spikelets. Normally,
only the sessile spikelets are fertile, but
the ARS scientists developed a plant that
produces seeds in both types of spikelets.
"We developed the productive sorghum line by inducing a mutation of
sorghum plants that allowed infertile
spikelets to grow and produce seed,"
said Xin. "All of the spikelets of the
ers and produce mature seeds, thereby
and yield in comparison to conventional
sorghum. The mutants may be crossed
with other sorghum lines, particularly
elite large-seeded lines, to improve
grain yield in sorghum and other related species. The mutation in the sorghum line we developed is stable and
can be passed on to other sorghum lines
through breeding."
At KSU, researchers are also trying to
produce hybrids with higher yields.
"Sorghum has high yield potential,
much higher than what we're getting
now. We know that," said KSU agronomist Tesfaye Tesso said. "We have been
tal lines that will be able to produce hybrids that can come closer to realizing
sorghum's yield potential. At the same
time, we need to make sure any new line
has an acceptable maturity range, good
standability, drought tolerance, good
head exsertion, and other necessary agronomic traits."
In 2013, hybrids from some of Tesso's
experimental pollinator lines topped the
200-bushel-per-acre mark on dryland
tests in Manhattan, Kansas, U.S., yielding greater than the top commercial
check hybrid there and proving that dry-

land sorghum can achieve yields comparable with that of dryland corn.
In KSU performance tests that year,
dryland corn averaged 184 bushels per
acre at Manhattan while dryland sorghum averaged 134 bushels per acre.
Some of the new experimental hybrids
in Tesso's trials either bested or evened
out that yield differential between dryland sorghum and corn.
Tests of the experimental lines in
tial of the new experimental lines compared with the commercial hybrids used
as checks.
"We think these new experimental
lines represent a real breakthrough in
the yield potential of grain sorghum in
the near future. According to our release
policy, we will be offering these new
pollinator and seed parent lines to commercial seed companies," Tesso said.
"Some of our new lines already have
been released. If the seed companies
are able to produce agronomically acceptable hybrids from these lines, there
should be a new generation of higheryielding grain sorghum hybrids coming
to producers in the near future."
Tesso's team also has several promising new ALS-resistant lines in advanced
stages of development. These lines are
resistant to a newly-developed herbicide that inhibits acetolactate synthase
(ALS), a plant enzyme.
EXPORT DEMAND
The United Sorghum Checkoff
Program is working to build larger export markets for U.S. sorghum. Exports
in 2014 were dominated by China,
which imported 168 million bushels
(4.26 million tonnes), 90% of total sorghum exports, the Checkoff said.
The Checkoff said it is building new
trade relationships by hosting trade
teams, attending export events and
overall relationship building. In 2014,
which brought together 30 U.S. buyers and 20 buyers from China, Japan,
Mexico and Spain.
China's sorghum consumption for the
March 2015 / World Grain / www.World-Grain.com

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World Grain - March 2015

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