- D. Lemmer, F.J. Kruger and I.J. Froneman
- Institute for Tropical and Subtropical Crops, Private Bag XI 1208, Nelspruit 1200
- 2002
The post-harvest evaluation of new cultivars and selections is crucial to ensure that only exportable cultivars with an adequate shelf life are recommended. This work is a continuation of a program started during the two previous seasons and this year included ‘Fay Zee Siu’, ‘Kwai May Pink’, ‘Haak Yip’ ‘Wai Chee’, ‘Nuomici’, ‘Souey Tung’, ‘Brewster’, ‘Salathiel’and ‘Bidum’, which were compared with the widely grown cultivars ‘HLH Mauritius’ and ‘McLean’s Red’. External colour retention when sulfur fumigated was found to be acceptable in all the new cultivars. Internally, all the cultivars were acceptable except for ‘Kwai May Pink’ , ‘Bidum’ and ‘Salathiel’ which showed aril discoloration which effectively disqualifies these cultivars. ‘Haak Yip’ and ‘HLH Mauritius’ produced the best results in terms of percentage mass loss. ‘Haak Yip’ and ‘HLH Mauritius’, ‘Souey Tung’, ‘Nuomici’ and ‘Wai Chee’ performed acceptably in terms of firmness retention. ‘Brewster’ and ‘Bidum’ disappointed with proneness to fungal infection. With regard to sulphur fumigation, ‘McLean’s Red’, ‘Bidum’, ‘Salathiel’ and ‘Brewster’ exhibited unacceptably high residues in the aril after 25 days of cold storage. ‘HLH Mauritius’, ‘Haak Yip’, ‘Kwai May Pink’ and ‘Souey Tung’ obtained values lower than the set limit of 10ppm, while ‘Fay Zee Sui’, ‘Nuomici’ and ‘Wai Chee’ obtained slightly higher values. The different cultivars were also treated with “Acid B”, the treatment developed by the ARC-ITSC for ‘HLH Mauritius’ fruit. Unfortunately, most cultivars reacted less favourably than ‘HLH Mauritius’. ‘Haak Yip’ was the only not showing a high degree of aril browning and/or developed undesirable after tastes when treated with this acid.
Summary:
- Purpose: To evaluate post-harvest quality of new litchi cultivars and selections for export suitability and shelf life, continuing a program from previous seasons.
- Cultivars evaluated: Eleven cultivars including Fay Zee Siu, Kwai May Pink, Haak Yip, Wai Chee, Nuomici, Souey Tung, Brewster, Salathiel, Bidum, compared with widely grown HLH Mauritius and McLean’s Red.
- External colour retention after sulphur fumigation was generally acceptable in all new cultivars.
- Internal quality: Most cultivars acceptable except Kwai May Pink, Bidum, and Salathiel, which showed aril discoloration disqualifying them for export.
- Best results for percentage mass loss were from Haak Yip and HLH Mauritius; others varied.
- Firmness retention: Haak Yip, HLH Mauritius, Souey Tung, Nuomici, and Wai Chee had acceptable firmness after storage.
- Brewster and Bidum were prone to fungal infection and performed poorly.
- Sulfur dioxide (SO2) fumigation residues were too high in McLean’s Red, Bidum, Salathiel, and Brewster; HLH Mauritius, Haak Yip, Kwai May Pink, and Souey Tung had residues below the 10 ppm limit.
- Acid B treatment, developed for HLH Mauritius, was less effective or caused browning in most other cultivars except Haak Yip.
- Storage simulated sea export conditions (25 days at 1°C + 7 days at 13°C) with regular evaluations.
- Conclusion: Haak Yip, Souey Tung, HLH Mauritius (mid-season) and Nuomici, Wai Chee (late-season) produce fruit with acceptable storage quality; Fay Zee Siu (early-season) performs moderately well; Kwai May Pink, Bidum, and Salathiel disqualified due to aril discoloration.
- Note on SO2 residues: Some cultivars require further screening in future seasons; environmental factors such as locality affect results and should be considered.