Effect of Photoperiod and Temperature On Tillering Rate and Rhizome Formation in Tall Fescue.

Temperature and photoperiod are key factors regulating plant growth and development. This study investigates the effects of temperature and photoperiod on tillers and rhizomes formation in tall fescue. Different genotypes were selected based on tillering ability and/or rhizome production. Plants were grown in growth chambers with a combination of different photoperiods and day/night temperatures; short photoperiod (9 hours) and low temperature (day/night at 15/10^oC) (SL), long photoperiod (18 hours) and low temperature (LL), short photoperiod and high temperature (day/night at 25/15^oC) (SH), and long photoperiod and high temperature (LH). Each genotype was replicated four times in four growth chambers. The SL plants showed significant increases in the number of tillers in one genotype. The LL plants also showed increase in the number of tillers. The number of rhizomes was increased under LL and LH conditions in three genotypes. Our results suggested that the responses of tiller and rhizome development to temperature and photoperiod varied with genotypes; in addition, longer photoperiod appeared to promote rhizome formation, regardless of temperature while lower temperature stimulated tiller production in some genotypes of tall fescue.