Tillering in ‘Grasslands Nui’ perennial ryegrass swards 2. Seasonal pattern of tillering and age of flowering tillers with two mowing frequencies

Abstract

Tiller density, tiller appearance rate (TAR), tiller death rate (TDR), tiller survival, and age of reproductive tillers were measured for 2 years in well fertilised, irrigated swards of ‘Grasslands Nui’ perennial ryegrass (Lotium perenne L.) mown either frequently (F) or infrequently (I). Seasonal changes in tiller density, TAR, and TDR were similar in F and I, with patterns being similar in timing in both years. TAR was greatest in the regrowth immediately after defoliation of the main group of reproductive tiller apices. TAR was approximately 60% of this peak value during summer, declined during autumn, then increased in winter. TDR was greatest during summer and lowest during winter. Tiller density declined during reproductive growth, increased rapidly after interruption of reproductive growth, declined during late summer and autumn, then increased again during winter. Tiller density was greater in F and I, the difference being caused by more rapid tillering in F. Survival of tillers was little affected by mowing treatment, and the half-life of tagged tillers was 36 -143 days. Only a small proportion of tillers became reproductive. In the first year, after autumn establishment of the sward, reproductive tillers were formed during winter. In the second year, tillers formed before winter provided the majority of flowering tillers. Secondary reproductive tillers elongated after the main group of reproductive tillers were decapitated, and these later developing tillers included tillers that appeared in winter and spring.

Keywords:

• ryegrass
• Lolium perenne
• tillering
• reproductive tillers
• ‘Grasslands Nui’