September 12, 2007

 

ARS: New sorghum variety ideal for both fuel and feed

 

 

The new low-lignin sorghum germplasm lines are being tapped by the Agricultural Research Service (ARS) of the US Department of Agriculture as livestock feed and ethanol resource.

 

Lignin is a "cellular glue" of sorts that gives rigidity and strength to plant tissues. It also helps plants fend off attacking insects and pathogens.

 

However, studies by ARS scientists Deanna Funnell, Jeff Pedersen and John Toy in Lincoln, Nebraska, show that reducing sorghum's lignin content can also be beneficial.

 

The Atlas bmr-12, one of 20 low-lignin lines the ARS team developed and tested in collaboration with University of Nebraska-Lincoln scientists Richard Grant and Amanda Oliver was one of the varieties tested for digestibility.

 

In the laboratory, the line scored higher on fibre digestibility than standard sorghum, which should result in higher milk production and higher beef gains when Atlas bmr-12 is fed to cattle.

 

The line's high fibre digestibility could also mean improved sorghum-to-ethanol conversion at processing plants, notes Funnell.

 

Interestingly, reducing the sorghum line's lignin didn't leave it more vulnerable to fungal attack in laboratory trials.

 

Funnell determined this by inoculating Atlas bmr-12 and another line, bmr-6, with Fusarium moniliforme fungi and examining the length of red-pigmented lesions that formed as the pathogen spread.

 

Both lines showed greater resistance to the fungus than a control group of standard sorghum that was used. Inside the stems of Atlas bmr-12, for example, fungal lesions were 78 millimetres (mm) long, versus 117 mm in other plants used for comparison in the trials.

 

Atlas bmr-12 and bmr-6 owe their unique balance of fibre digestibility and disease resistance to two genes for the brown midrib trait, which Pedersen incorporated into the sorghum lines during breeding stages.