STOLON FORMATION AND SIGNIFICANCE FOR SWARD TILLER DYNAMICS IN PERENNIAL RYEGRASS

Abstract

In a pot trial to investigate stolen formation in perennial ryegrass (Lolium perenne L.). 4 genotypes of ryegrass tested all formed stolons. After burial with approximately 30 mm soil in August, cutting and burial, or cutting alone, stolen numbers in November were 18.8 and 3 (SED 3) per plant, respectively. In a grazed ryegrass sward stolen lengths were measured at intervals between May 1987 and April 1988, and for hard and lax grazed plots respectively, were 58 and 96 m/m2 in May, increased to 137 and 164 m/m2 in December, then declined to 47 and 74 ml m2 in April 1998. Active stolon formation in the field began when tillers were buried by earthworm activity and stock trampling in winter. It appears that stolen formation in ryegrass is a response to a seasonal cycle of burial similar to that for white clover. Studies of tagged tillers indicated a pattern of sward renewal in early summer by rapid production of large numbers of tillers from stolons at the base of dying flowering tillers. Other research results suggest that this pattern of sward renewal in perennial ryegrass may be widespread. Implications for grazing management are briefly discussed. Keywords: tiller appearnace rate, perennation, carbohydrate, perennial ryegrass, stolen formation