Stoneville, Mississippi
February 1, 2007
By Robert H. Wells
Delta Research and Extension Center,
Mississippi State University
Rice producers will need to
consider other variety options this year after losing the
popular variety Cheniere to contamination.
“The discovery in August of Liberty Link Rice 601 contamination
in U.S. commercial long-grain rice supplies will significantly
affect variety selection for Mississippi rice producers in
2007,” said Tim Walker, assistant agronomist at Mississippi
State University’s Delta Research and Extension Center in
Stoneville.
Liberty Link 601 is a genetically modified trait in rice that
provides resistance to the Liberty Link herbicide. Lucrative
markets, such as the European Union, will not purchase rice with
this trait.
“As of now, the only known variety that has been contaminated
with the Liberty Link 601 line is Cheniere,” Walker said.
“Cheniere was planted on about 25 percent of the rice acreage in
Mississippi in 2006. However, in an attempt to purge the rice
supply of the Liberty Link 601 line, the industry has decided
not to plant Cheniere in 2007. Growers must select other
varieties for fields where Cheniere was popular.”
Growers primarily planted Cheniere on silt-loam soils and on
recently land-leveled fields because of the variety’s tolerance
to the physiological disorder straighthead.
“Variety selection is critical for Mississippi rice growers,”
Walker said. “Factors such as lodging, disease resistance, yield
potential and milling qualities are all very important factors
that growers consider when selecting which varieties to plant.
Few, if any, varieties offer a complete package where there are
essentially no weaknesses. Therefore, growers should choose what
negative factors they can live with.”
Growers’ check-off dollars through the Mississippi Rice
Promotion Board have sponsored Walker’s research on variety
performance. Walker, who has conducted yield trials on silt-loam
soils and land-leveled fields, said growers need to know their
options for planting rice in the environments where Cheniere was
popular. Replacement options include the hybrid rice XL723,
Cocodrie, Wells, Cybonnet, Trenasse and Sabine.
Pros and cons of XL723
“As we have come to expect, the hybrid XL723 outperformed all
inbred varieties for the last three years with an average yield
advantage of 18 to 25 percent more bushels per acre,” Walker
said. “XL723 offers excellent milling quality as long as the
rice is harvested at optimum moisture.”
Other advantages of XL723 are its field tolerance to
straighthead and its resistance to the rice disease blast.
Some drawbacks Walker pointed to include XL723’s potential to
lodge and shatter during severe weather and its expense. The
seed cost for all hybrids is considerably higher than inbred
varieties.
Cocodrie …
Dwight Kanter, rice breeder and agronomist at the Stoneville
center, said another variety replacement option is Cocodrie.
Cocodrie
“Cocodrie was grown on about 42
percent of the production acreage in Mississippi in 2006,”
Kanter said. “It is a popular commercial, semi-dwarf, long-grain
cultivar noted for its sustained, good to excellent yields and
milling percentages.”
However, Walker found Cocodrie to be the most susceptible
variety to straighthead on silt-loam soils and recently
land-leveled fields.
Growers can almost eliminate the potential for straighthead if
they drain the fields and allow the soil to crack so oxygen will
return to the soil.
“However, Cocodrie reaches mid-season almost one week earlier
than most other varieties,” Walker said. “As a result, draining
and re-flooding is often difficult due to the narrow window
between initial flooding and midseason.”
Wells
MSU Extension rice specialist Nathan Buehring said the variety
Wells also will be a good replacement for producers who grew
Cheniere in 2006.
“This variety is taller than most varieties we grow, so lodging
may be an issue,” Buehring said. “We do recommend going with a
lower preflood nitrogen rate to help prevent lodging.”
Walker suggested reducing Wells’ preflood nitrogen rate to 90
pounds of nitrogen per acre and reducing its seeding rate to
about 65 to 70 pounds of seed per acre. Yield potential for
Wells is good to excellent.
“If field conditions prevent a continuous flood being maintained
during the growing season, the risk of having blast increases
tremendously,” Walker said.
Cybonnet
Cybonnet also may be considered in 2007, but yields may not
match Cocodrie or Wells. It has moderate to good lodging
resistance.
“Cybonnet was released recently as Arkansas’ first semi-dwarf
variety,”
Walker said. “It has good field tolerance to straighthead and is
also rated moderately resistant to blast. Sheath blight can
inhibit Cybonnet from reaching its maximum yield potential, but
foliar fungicides have been worth their price when the pathogen
is aggressive.”
Trenasse
Another option for some growers is Trenasse.
“It is Louisiana’s newest non-Clearfield, long-grain, semi-dwarf
variety,” Walker said. “For growers who do not mind harvesting
rice about five days earlier than normal, Trenasse may be of
interest.”
Walker said because of Trenasse’s earliness, insect and disease
monitoring will be critical. It is rated very susceptible to
sheath blight and is subject to lodging under high-yielding
conditions.
“As with Wells, preflood nitrogen rates for Trenasse should be
dialed back to about 90 pounds per acre, and seeding rates
should be reduced to
65 to 70 pounds per acre,” Walker said.
Yields for Trenasse are typically not as high as other varieties
due to its earliness.
Sabine
Growers may consider Sabine as another possible option.
“Sabine is a new release from Texas that has Dixiebelle cooking
qualities,” Walker said.
Dixiebelle qualities are grain processing characteristics that
make a variety desirable for use in the canning and parboiling
industries.
“In limited observations, Sabine has shown average yield
potential and excellent milling quality,” Walker said. “Because
of its susceptibility to sheath blight, a fungicide may be
necessary to protect yields.”
Walker said little is known about Sabine’s field tolerance to
straighthead, but in limited observations, straighthead has not
been detected in Mississippi.
Buehring said Sabine typically yields lower than other varieties
such as Cocodrie and Wells in trials.
“However, growers get a premium for growing this variety because
of its superior cooking qualities,” he said. |