Selection for persistence of endophyte-free meadow fescue under intensive grazing versus frequent mowing

Abstract

Background

Meadow fescue (Schedonorus pratensis (Huds.) P.Beauv.) is highly adapted to managed rotational grazing systems with sufficient rest periods to promote regrowth and sward longevity. It is not well adapted to intensive grazing with set stocking that results in limited regrowth periods and defoliation heights less than 10 cm.

Methods

Six populations were identified on farms that used relatively intensive grazing with a combination of set stocking and rotational grazing and a relatively sparse population density of meadow fescue plants. These populations were subjected to three cycles of selection for persistence on their farm of origin and on an experimental research farm where the plots were frequently mowed with a residual sward height of 5 cm. Original and selected populations were evaluated under both defoliation regimes.

Results

Five of the six populations responded to selection with increased persistence under grazing, but four of these had correlated selection responses toward reduced forage accumulation, suggesting selection for a more prostrate growth habit.

Conclusions

Selection under frequent mowing led to some increases in persistence, but the increases were significantly less than for the selections under grazing pressure, strongly indicating selection pressure for different plant traits between grazing and mowing.