Tiller Development and Growth in Switchgrass

Abstract

Switchgrass accessions collected from throughout the Southeast were grown without harvesting for 8 years. Measurements were made on tiller generation, rate of clone spread, time of tiller initiation, and number of tillers per given area. Data collected show that tillers are true biennials, buds at the base of shoots growing as rhizomes the first year and growing as green leaf bearing shoots the second when an inflorescence is produced. Rate of clone spread is determined by rhizome length. Ecotypes with short rhizomes produce tight clones which are pushed above the soil line by roots. In some of these varieties, actively growing tillers will be found only at the edges of the clones, not within the central region. Accessions which have both short and long rhizomes tend to spread much faster and stands are more stable than accessions which produce only short rhizomes. Tiller density ranged from 12-30 per dm2 on sod forming ecotypes to 20-35 per dm2 on bunch types.