Two new sugarcane varieties released earlier this year and “energy cane” were featured at the LSU AgCenter's recent sugarcane field day at the Sugar Research Station, St. Gabriel, La.
The new varieties — L 99-226 and L 99-233 — were developed by the LSU AgCenter in cooperation with USDA's Sugarcane Research Unit in Houma, La., and the American Sugar Cane League in Thibodaux, La.
The new varieties come in the nick of time because the current most popular variety planted in Louisiana has been plagued with rust problems this year. LCP 85-384 has been the leading variety planted in the state, according to Kenneth Gravois, LSU AgCenter sugarcane breeder and resident coordinator of the Sugar Research Station.
Gravois said L 99-226 produced the highest total sugar per acre in field tests.
Both new varieties appear to have good resistance to sugarcane rust disease, and L 99-226 has particularly good resistance to the sugarcane borer. The sugarcane breeder cautioned growers to be careful to plant insect-resistant varieties near populated areas because of the concerns for applying pesticides near homes, schools and businesses.
Gravois said two additional varieties in the final stages of evaluation show promise for release in the next year or two, which is good news for sugarcane growers. Not only has LCP 85-384 become more susceptible to rust, but it has lost “vigor” over the years since its release in 1999.
“We have a lot of replacements for 384 and good potential varieties in the pipeline,” Gravois said.
Ben Legendre, LSU AgCenter sugarcane specialist, said research into what's called energy cane — sugarcane that produces large amounts of plant matter with high sugar content — began in the early 1970s following the oil embargo. But after the embargo ended and gasoline prices retreated, interest waned.
“Energy cane has been around 30 to 35 years,” Legendre said. “It's not really new.”
Legendre said sugarcane varieties aimed at energy production are not appropriate for sugar production. He said researchers are looking for varieties that produce high yields of plant material — called biomass — and have capabilities for use in energy production.
While ethanol is currently produced from corn and other grains and can be produced from sugar, scientists are looking at ways to economically convert biomass — entire plants — to fuels. Experts call this process cellulosic conversion.
Until cellulosic conversion is affordable, sugar won't be considered as a major feedstock for ethanol, said Mike Salassi, an economist in the LSU AgCenter's Department of Agricultural Economics and Agribusiness.
The two basic feedstocks for making ethanol are grain and sugar crops, Salassi said. Most of the ethanol manufactured in the United States comes from corn.
“The choice is based on cost,” Salassi said. “A country is going to use whatever is cheapest.”
He said while corn is the primary source of ethanol in the United States, sugar is the leading source in Brazil, for example. “Sugarcane is a relatively expensive crop to grow compared with corn,” he said.
Salassi said that in addition to ethanol, corn also yields other byproducts that reduce the relative cost of manufacturing ethanol from that crop. He said currently ethanol can be produced from corn for about $1.05 per gallon while ethanol costs between $1.27 per gallon (if it's made from molasses) and $3.48 per gallon (if it's made from raw sugar).
U.S. cane sugar averages about 20 cents per pound while the world market for sugar is about 13 to 14 cents per pound, Salassi said.
“Cellulosic conversion of biomass to ethanol could reduce the cost of converting sugarcane into ethanol. Feedstock is a major cost item,” he said. “If you can get that feedstock at a good price, that's what you'll use. This is an important area to keep looking at to see what role sugarcane can play.”
Legendre said energy cane has different characteristics than sugarcane. “We're looking at higher energy-output and lower energy-input plants that can regrow almost forever,” he said. “Some of these varieties are so vigorous we can reduce the cost of production.”
If its energy potential is high enough, energy cane could be used as a boiler fuel, Legendre said.
The sugarcane specialist said the LSU AgCenter has three varieties up for consideration for release as energy cane varieties. The research into those varieties is being done with dedicated funding from the American Sugar Cane League.
Regarding the current year's sugarcane production, farmers have a growing concern about sugarcane rust infesting LCP 85-384, the leading sugarcane variety grown in Louisiana.
Jeff Hoy, a plant pathologist with the LSU AgCenter, said producers faced a “severe epidemic of rust this year” because of a dry spring and early summer.
Hoy said the best answer to the rust problem is new varieties. “Rust can overcome resistance,” Hoy said. For the future, “rust is going to be a cyclic problem at the very least.”
To help producers combat sugarcane rust problems, AgCenter researchers are evaluating fungicides for on-farm use. They're assessing various fungicides individually and in combination as well as the timing and number of applications, Hoy said.
“We're looking at efficacy,” Hoy said. “Can they control rust?”
Because some fungicides can control the disease but can't stop it, Hoy said multiple applications of fungicides will most probably be necessary.
Concerning new varieties to replace 85-384, Hoy said the biggest potential is smut disease. All the new varieties introduced in the past few years have the potential to pick up smut, he said.
“I think smut could stay at manageable levels if growers use healthy seed,” Hoy said. “Growers should be focused on healthy seed cane. This is not the area to reduce costs.”
Weather also plays an important part in sugarcane diseases, Hoy said. He cited the mild winter of 2006 as a contributor to increased disease problems. “Hard freezes can work in our favor” to reduce diseases, he said.