USDA ARS scientists develop higher yielding sorghum plants

By USDA Agricultural Research Service, Sharon Durham | February 11, 2015

A new sorghum plant developed by USDA scientists can produce more seeds than conventional varieties currently grown by farmers.

Agricultural Research Service molecular biologist Zhanguo Xin and plant geneticist Gloria Burow at the Plant Stress and Germplasm Research Unit, along with lab director and research leader John Burke, at the ARS Cropping Systems Research Laboratory in Lubbock, Texas, developed a mutant sorghum plant that produces 30 to 40 percent more seeds.

ARS is the USDA’s chief intramural scientific research agency.

The researchers developed the higher yielding sorghum by taking advantage of a plant part called a “spikelet.” A spikelet is a cluster of florets within the panicle, a type of flower cluster found in some 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 sorghum plant that produces seeds in both types of spikelets.

The team developed the productive sorghum line by inducing a mutation in sorghum plants that allowed infertile spikelets to grow and produce seed, according to Xin. An induced mutation is produced by treatment with a mutagen, like radiation or a chemical agent such as ethyl methane sulfonate. The mutation resulted in an overall increase in size and volume (length, width, and thickness) of the sorghum panicle.

All of the spikelets of the new sorghum plant develop into flowers and produce mature seeds, thereby significantly increasing seed production 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, according to Xin.

A sample of at least 2,500 seeds of the new multiseeded sorghum has been deposited with the American Type Culture Collection for future research.

Read more about this research in the February 2015 issue of Agricultural Research magazine.