Photoperiod and temperature effects on rhizome production and tillering rate in tall fescue [Lolium arundinaceum (Schreb.) Darby.]

Temperature and photoperiod are key factors regulating plant growth and development. The objective of this study was to investigate the effects of temperature and photoperiod on tillering and rhizome formation in tall fescue [Lolium arundinaceum (Schreb.) Darby.]. 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 h) and low temperature (day/night at 15/10°C) (SL), long photoperiod (18 h) and low temperature (LL), short photoperiod and high temperature (day/night at 25/15°C) (SH), and long photoperiod and high temperature (LH). The SL treatment resulted in significant increases in the number of tillers in the experiment and Genotype 1109 produced the maximum number of tillers. The number of rhizomes was increased under LL and LH conditions in three clonal lines. 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, whereas lower temperature stimulated rapid tiller production in some genotypes of tall fescue. This study will help to determine the performance of tall fescue under the longer/shorter photoperiod and variable temperature conditions in different parts of United States.