Reproductive development of four top flowering annual clovers

Abstract

A series of field experiments aimed to quantify reproductive development of four clover species, arrowleaf (Trifolium vesiculosum), balansa (T. michelianum), gland (T. glanduliferum) and Persian (T. resupinatum), for introduction to New Zealand dryland pastures. The duration from emergence to flowering was related to the length of, and direction of change in, photoperiod at the time of first trifoliate leaf appearance. Autumn-sown crops that emerged into a decreasing photoperiod had a longer vegetative growth before they turned reproductive. The time to flower became shorter with increasing photoperiod until the longest day of the year, before it began to slow down as photoperiod decreased towards late summer. Prima gland clover flowered earlier (500–1216 degree-days) than Bolta balansa (600–1733 degree-days), Cefalu arrowleaf (940–1834 degree-days) and Mihi Persian (1047–2610 degree-days) clovers. The duration from pollination to physiological maturity was 274–689 degree-days for Cefalu, 185 degree-days for Bolta, 256 degree-days for Prima, and 425 degree-days for Mihi. The differences in flowering time suggests the suitability of Prima gland clover for areas that dry out quickly in late spring, Bolta balansa clover for areas of wet winter and dry summer, and Cefalu arrowleaf and Mihi Persian clovers for areas that receive higher spring rainfall.