Flowering and seed formation of Stylosanthes humilis as influenced by time of sowing

Abstract

Sowings of a Greenvale line of Stylosanthes humilis were made at intervals of about 14 days from December 26 to April 19 on the Queensland Darling Downs and irrigated. Days from sowing to flowering and node number at flowering decreased in late summer sowings but March and April sowings did not flower before frost killing in May. Inflorescence number was positively related to earliness of sowing, but the pattern of relative increase in inflorescence number with time was similar for all flowering treatments. The rate of inflorescence appearance was not well related to screen temperature 1.5 m above ground, but quadratic functions are reported relating floret number per spike to mean temperature, floret maturity to maximum temperature, and floret abortion and seed number per spike to mean night temperature. It is suggested that seed formation ceases at 12¦C mean night temperature or 9¦C minimum temperature.