Improvement of the Feeding Value of Senescent Grass Pastures by Molecular Genetic Manipulation

Senescent grass pasture has low feeding value end is the major limitation to animal productivity during summer in annual environments. The loss of fructan from the stems of temperate grasses as they senesce contributes significantly to the decline in feeding value of the grass, Temporary retention of fructan during senescence achieved by treating grass with a herbicide increases both the feeding value of the grass and the productivity of animals grazing the modified pasture. We have identified an enzyme responsible for initiating the loss of fructan from stems of Lolium rigidum. It has been purified, characterized and will be used to isolate the gene encoding its activity. A strategy to use this clone to regulate the hydrolysis of fructan in stems of grasses during senescence is discussed,