BROWN MIDRIB SORGHUM FORAGE

Dr. Tom Burmood

The brown midrib trait was discovered in corn at Purdue University in 1926. Early studies revealed the trait resulted in lower fiber and lignin within the plant. Brown midrib corn hybrids for silage were introduced to the market in the late 1970’s, but withdrawn due to standability issues. Cargill Hybrid Seed Co re-introduced brown midrib corn for silage in the 90’s and currently the trait is available in hybrids from Mycogen. In 1978 the mutant was identified in sorghum. Research indicated the trait reduced lignin in sorghum comparably to corn and sparked interest for utilization in sorghum forage production.

Sorghum forage is produced from different hybrid types which include hybrid forage sorghum, hybrid sorghum x sudan crosses and sudans. . Hybrid forage sorghums typically produce grain and are used for silage. Sorghum x sudan crosses may or may not produce grain and can be used for silage, but also are used for green chop, pasture or hay production as well. Sudans are used mostly for grazing. The brown midrib trait is commercially available in forage sorghum and in sorghum x sudan hybrids. Because of the versatility of use, most BMR hybrids are sorghum x sudan crosses. Currently, three genes, BMR-6, BMR-12 and BMR-18 are used in the sorghum industry to produce primarily brown midrib hybrids. Although agronomic issues such as standability remain, forage analysis and feeding trials have demonstrated improved digestibility from brown midrib forage. Dry matter yields have been comparable to conventional sorghum forages and competitive with corn silage.