- J Fivaz
- Mariepskop Estate, Private Bag X3009, Hoedspruit 1380
- 1998
The litchi still fails to be one of the major horticultural crops of South Africa and of the world, due to low and irregular bearing. In many instances trees produce very good yields in one season, but what is typical is the poor flower production the following season brought about by an “off”-year situation in biennially bearing trees. A solution to the problem of low and irregular bearing would be to concentrate on effective litchi tree management, including manipulation, irrigation and fertilization. During the seasons of 1994 and 1995, detailed phenological cycles of the two main commercial cultivars were studied in different production areas.
Summary:
- The study focuses on phenological cycles and seasonal starch fluctuations in HLH Mauritius and McLeans Red litchi trees, aiming to understand factors affecting low and irregular bearing in litchi crops.
- Litchi trees often show biennial bearing patterns, with high yields in one season followed by poor flowering and yields in the next, which is a major challenge for commercial production.
- Detailed phenological cycles were observed in both on-year (high flowering) and off-year (vegetative flush) trees, with on-year trees showing higher starch concentrations in branches before flowering.
- Starch levels in branches, roots, and main stem strongly depleted during fruit growth, reaching minimum values at harvest, while starch in fruit increased significantly up to harvest.
- Off-year trees did not show significant starch depletion in terminal branches, indicating differences in carbohydrate allocation between on- and off-year trees.
- Pruning or fruit removal after harvest did not significantly affect starch concentration in branches but led to increased starch in new growth.
- Starch content in HLH Mauritius fruit ranged from 654.21 to 969.66 mg/g dry mass, with the highest proportion in the seed, followed by the aril and peel; a 100 kg yield removes about 2.97 kg of starch from the tree.
- McLeans Red fruit had higher starch content (1,197.59 mg/g dry mass), with the majority also in the seed; a 100 kg yield removes about 3.83 kg of starch.
- Understanding starch distribution at different phenological stages provides valuable data for optimizing tree management and manipulation practices to improve litchi yields.