Seasonal patterns of root, tiller and leaf production in a Grasslands Ruanui ryegrass sward

Abstract

In a Grasslands Ruanui perennial ryegrass (Lofium perenne L.) sward at Palmerston North, root mass, root appearance, tiller population density, tiller appearance and death rates, and leaf extension and leaf appearance rates were measured at 2-monthly intervals over a 12-month period, commencing November 1988. Tiller appearance was lowest in November, but was also low in May, increasing to a peak in August. Root appearance showed a pronounced peak in August. Leaf extension and leaf appearance rates were low during the period of high root and tiller formation in August, but high in November when tiller and root formation were low, suggesting co-ordination of these processes, with sequential activation of tillering, root formation and leaf formation activity winter. Principal component analysis to gain an objective overview of these data indicated a primary peak of activity in August (spring), and a secondary peak in March (autumn). The seasonal patterns observed for Grasslands Ruanui ryegrass appear to be different from those reported in the literature for Ellett and Grasslands Nui cultivars. ---.----._- - - - Keywords: leaf extension rate, Lolium perenne, principal component analysis, root growth, tiller appearance