Research Description:

Evaluation of Transgenic Bahiagrass

Bahiagrass is the predominant pasture grass grown for beef cattle in many areas of the Southeast due to its disease resistance, low fertility requirements, ability to withstand drought conditions and persistence under heavy grazing. Nutritive value, however, may be low due to increasing lignin content as the plant matures. An antisense version of O-methyltransferase (OMT), a gene in the lignin biosynthetic pathway, was transformed into apomictic Tifton 7 bahiagrass using particle gun bombardment.

The plasmid containing the OMT gene also contained the BAR gene conditioning resistance to glufosonate herbicide. Plants (35) of the T0 generation and four non-transformed control clones were transplanted as spaced plants to an approved field evaluation nursery in spring 2002. Preliminary analyses of acid detergent lignin (ADL) content in 2003 revealed a wide range, but the mean of the ten plants with lowest ADL content was 30% below the mean of the controls (P=0.01).

Apomictic seed from these ten T0 plants was produced under bagged greenhouse conditions. In spring 2004 a progeny evaluation experiment was established as four replications of 14 entries (the 10 T1 progeny rows, two non-transformed controls, Tifton 7 and Argentine) with five plants per row. The original T0 plants were sampled for ADL content at 4 and 8 wk regrowth in 2004 and the T1 progeny rows will also be evaluated. All T1 apomictic progeny were evaluated for glufosonate resistance prior to transplanting to the field and all were resistant. DNA will be extracted from the samples collected and a southern blot test will be performed to further prove the presence of the OMT gene.