- J. Kift and N.J.R. Roets
- ARC-Institute for Tropical and Subtropical Crops, Private Bag X11208, Nelspruit 1200
- 2003
Phenological patterns of HLH Mauritius and Wai Chee were studied in the Nelspruit and Malelane areas. The intervals between consecutive growth cycles were shorter in the warmer Malelane area where both cultivars produced two post harvest vegetative flushes before flower initiation. In the Nelspruit area only one post harvest vegetative flush was observed in both cultivars. A drop in average daily temperatures to 20°C and lower triggered HLH Mauritius flower panicle formation and floral buds became visible during June. Wai Chee branches that had young growing buds during July and August flowered well. All the growth that was initiated before and after the cold weather produced vegetative flushes while intervals of warmer days during the winter period reduced flowering and gave rise to leafy panicles and vegetative growth.
Summary:
The study examined phenological patterns of two litchi cultivars, HLH Mauritius (early flowering) and Wai Chee (late flowering), in the Malelane and Nelspruit areas of South Africa.
Warmer Malelane area had shorter intervals between growth cycles; both cultivars produced two post-harvest vegetative flushes before flowering there.
Cooler Nelspruit area had only one post-harvest vegetative flush before flowering for both cultivars.
Flower initiation in HLH Mauritius was triggered by a drop in average daily temperatures to 20°C or lower, with floral buds visible during June.
Wai Chee branches with young growing buds in July and August flowered well.
Growth before and after cold weather resulted in vegetative flushes; periods of warmer days in winter reduced flowering and caused leafy panicles and vegetative growth instead.
Different litchi cultivars require different minimum temperatures for flower initiation: “Hill Litchis” like HLH Mauritius need around 12°C or lower, while “Water Litchis” like Wai Chee require temperatures as low as 6°C.
Flowering is better with a drop in temperature rather than constant cold; exposure to temperatures above 20°C for too long reduces flowering.
Manipulation of vegetative flushes before winter is vital as litchi trees do not grow continuously; growth intervals lengthen at lower temperatures.
HLH Mauritius in Malelane showed two distinct vegetative flushes post-harvest; in Nelspruit, only one flush occurred due to later harvest and cooler temperatures.
Wai Chee flowered better in cooler Nelspruit (52.6% flowering) than in warmer Malelane (20% flowering).
The second vegetative flush in Wai Chee in Malelane negatively affected flowering; it is recommended to prevent this flush using growth inhibitors.
HLH Mauritius benefits more from a temperature drop than Wai Chee, which requires a longer cold period to induce flowering.
In conclusion, temperature patterns and timing of growth cycles significantly affect flowering success in both cultivars in different production areas.