- D Sivakumar1 , L Korsten1 , RB Cronje2 and P G Mostert3
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1Post harvest Science, Department of Microbiology and Plant pathology, University of Pretoria, Pretoria 0002, SA
2Agricultural Research Council-Institute of Tropical and Subtropical Crops, Private Bag Xl 1208, Nelspruit 1200, SA
3Mostert Consulting Services, PO Box 3799, Nelspruit 1200, South Africa - 2007
Litchi (Litchi chinensis Sonn.) cv. Mauritius is a popular cultivar exported to the European market due to its attractive red colour and excellent fruit quality. Five different crop management treatments regimes (T1 to T5) were tested according to Cronje et al., 2006 in comparison with the currently adopted regime in a commercial orchard to improve the fruit quality attributes. T5 regime with Ca(N03)2 foliar spray application increased the fruit Ca and firmness. Leaf Ca content was higher than the fruit Ca. T3 and T5 increased the fruit K content. A moderate correlation between leaf K and fruit K and a positive correlation between fruit K and SSC were evident.
Summary:
- The study evaluated six different crop management treatment regimes (T0 to T5) on the fruit quality of litchi cv. Mauritius at commercial harvest in South Africa.
- Litchi cv. Mauritius is valued for its attractive red color and fruit quality, important for export primarily to the European market.
- Treatments involved various applications of fertilizers (N, P, K), micronutrients (Zn, B, Cu), growth regulators (cytokinin, auxin), girdling, and foliar sprays such as CaNO3 and KNO3.
- Key fruit quality attributes measured included fruit firmness, soluble solid concentration (SSC), titratable acidity (TA), and mineral content (Ca, K).
- The T5 treatment, which included CaNO3 foliar spray and multiple nutrient sprays plus girdling, led to the highest fruit firmness and fruit calcium content.
- Fruit Ca was positively correlated with firmness (R2=0.85), and leaf Ca was higher than fruit Ca but not a reliable predictor of fruit calcium status.
- Treatments T3 and T5 increased fruit potassium content, which correlated moderately with leaf K and positively with SSC, enhancing sweetness and flavor balance (SSC/TA ratio).
- The use of KNO3 at the fruitlet stage and CaNO3 sprays contributed to improved fruit quality by increasing firmness, sweetness, and mineral content.
- The study recommends repeating these treatments over multiple seasons and sites for consistent commercial recommendations.
- The research was supported by the South African Litchi Growers Association and a government technology program.