Inoculated wheats: self fertilising crops

PhD student Craig Wood at the University of Sydney: GRDC-supported research has produced a lab crop of green wheat plants without added fertiliser. The secret ingredient? Inoculation with fertiliser-producing bacteria.

A team of scientists at Sydney University has succeeded in inoculating wheat seedlings to produce their own nitrogen, and has grown them to maturity in glasshouse trials.

The GRDC-supported research involved three years of intensive analysis and extensive screening of strains of the microbe Azospirillum.

Reduction in the use of synthetic fertilisers would mean a huge saving in the cost of wheat production, and would help the environment. However, as nitrogen is the main limiting factor in Australian grain production after water, farmers have little choice but to continue to use fertilisers in order to maintain or increase yields.

The scientists, led by Ivan Kennedy, aimed to mimic the relationship which naturally occurs between legumes and nitrogen-fixing Rhizobium bacteria, in which the bacteria take nitrogen from the air and convert it to a form that the plant can use.

Nitrogen fixation is a complex process and previous attempts to incorporate it into other plant systems have failed.

According to Professor Kennedy, the inoculated plants had higher vegetative growth and more grain in the heads. Importantly, the soil used in these trials was similar to that producing wheat crops all around the country, but without the fertiliser. Field trials are the next step. The potential savings and environmental benefits of such inoculant bio-fertilisers may be immense.

Program 3.5.2 Contact: Professor Ivan Kennedy 02 9351 3546