Effect of temperature on the growth of Lachenalia cv. Ronina during the bulb preparation phase

Abstract

Lachenalia cultivars have excellent characteristics as flowering pot plants. The effect of three temperature regimes on the growth of small bulbs of Lachenalia cv. Ronina to flowering size (± 7 g) was studied. Potted bulbs were grown in three temperature controlled cabinets with temperature regimes chosen to represent a cold, a moderate and a warm winter. Plants were destructively harvested to investigate environmental effects on plant morphology and additionally flowering, anthesis and flower senescence were monitored. Under all three temperature regimes bulb growth followed a typical sigmoidal curve. Root growth does not support optimal bulb size under the different temperature regimes. Leaf growth in plants under the moderate temperature regime was more vigorous and foliage had a healthier appearance than in the low and high temperature regime treatments. Inflorescence emergence was earlier under the low and moderate temperature regime. At the end of the growing season, bulbs grown in the high temperature treatment formed secondary inflorescences. The best temperature regimes for Lachenalia bulb production were the low and moderate temperature regime which represented the cool and moderate winter climate in South Africa.