Flowering Responses of Easter Cactus Clones at Optimal and Supraoptimal Temperatures

Abstract

The effects of temperature and clonal genotype on flowering of Easter cactus (Rhipsalidopsis Britton & Rose) were investigated in two experiments. Plants of `Crimson Giant', `Evita', `Purple Pride', and `Red Pride' were exposed to 6 weeks of either 10C or 18C night temperature (NT) under 9- to 9.5-hour natural daylengths (ND), and afterwards were forced at 18C NT and long days (LD). All clones produced fewer flowers when exposed to 18C and ND as compared with 10C and ND; however, the clones varied significantly in their flowering responses. Relative to 10C NT and ND, exposure to 18C NT and ND resulted in an 84% to 95% decrease in the number of flower buds for `Evita', `Purple Pride', and `Red Pride', but only a 50% decrease in the number of flower buds for `Crimson Giant'. In another experiment, 23 clones were exposed to 18C NT and 8-hour short days for 6 weeks, then forced at 18C NT and LD. The clones exhibited differences in percentage of plants flowering, days to flowering, percentage of apical phylloclades flowering, and number of flower buds. `Crimson Giant' outperformed all other clones. Further breeding and selection may yield genotypes that flower more prolifically at 18C minimum than current cultivars.