Flowering in Townsville lucerne (Stylosanthes humilis). 2. The effect of latitude and time of sowing on the flowering time of single plants

Abstract

The flowering times of seventeen selections of Townsville lucerne (Stylosanthes humilis HBK) have been studied at three localities and six sowing dates. The selections were grown as spaced plants and the full range of maturity types (Cameron 1965) was represented. The repeatability of flowering time between years was high, with no differences in the order of flowering of the different maturity groups. There was a range of 56 days in flowering time between the early and late groups for a December sowing, but this was reduced to 8 days for a March sowing. The maturity type groups were not clearly differentiated at the March sowing. Most selections flowered progressively later the more southerly the location and this effect was greatest for the early maturity types. Most of the flowering time responses were closely related to changes in daylength and very similar to results previously obtained in controlled conditions (Cameron 1967a). However, low temperatures, shading and moisture stress also delayed the flowering of some selections.