Vegetative development of four annual clovers

Abstract

A field experiment with 10 sowing dates quantified thermal time requirement for seedling development of arrowleaf, balansa, gland and Persian clovers. A base temperature (Tb) of 0⁰C was found for all species. Balansa and Persian clovers required ~213⁰C d from sowing to first leaf appearance compared with 231⁰C d for arrowleaf and 221⁰C d for gland clover. The phyllochron for these annual clovers was affected by photoperiod at emergence. For example, the phyllochron for balansa clover was 82⁰C d when plants emerged into a 13.6 hour with decreasing photoperiod but only 44⁰C d when plants emerged into a 15.6 hour with increasing photoperiod. These differences in phyllochron also affected the time of axillary leaf appearance. A slower phyllochron resulted in longer time to the first axillary leaf.