Effect of Different Preharvest Treatment Regimes on Fruit Quality of Litchi Cultivar ‘Maritius’

ABSTRACT

Preharvest treatments were tested with commercial practice to improve yield, fruit size, weight, and quality attributes of litchi cv. ‘Maritius’. Treatment regimes included commercial control: T _C = control [30% nitrogen (N) after harvest and 50% at flowering, 20% at fruit set; Potassium (K) 40% in March, 60% at flowering; Lime (CaSO₄) in March, zinc (Zn), boron (B), and copper (Cu) sprays at flowering]; T ₁ = same as T _C, but an additional application of low biuret (LB) urea (1%), cytokinin (150 mL/100 L water), (2%) potassium nitrate (KNO₃) applications; T ₂ = same as T ₁ + auxin, (40 ppm); T ₃ = same as T ₂, however, auxin was replaced with 2% KNO₃ sprays; T ₄ = same as T ₂, however, auxin and KNO₃ replaced by girdling; T ₅ = T _C + T ₁ + Maxim® + 2% KNO₃ twice + girdling + 2% calcium chloride (CaCl₂) foliar spray twice. Calcium chloride increased the fruit calcium (Ca), firmness, and skin color. Some of the positive correlations were leaf potassium (K) and fruit K; fruit K and soluble solid concentrations (SSC); skin Ca and color value “a”. Potassium nitrate and CaCl₂ affected the K/Ca ratio in the fruit.

Keywords:

• preharvest treatments
• quality attributes
• potassium
• calcium
• nitrogen in litchi fruit

ACKNOWLEDGMENTS

This work was partly supported by a grant from the South African Litchi Growers’ Association and Technology and Human Resources for Industry Program (THRIP), a partnership program funded by the Department of Trade and Industry and managed by the National Research Foundation (NRF). We express our thanks to Hall & Sons, Nelspruit South Africa for providing facilities to conduct the trials in their commercial orchards and also to Ms. Sanette Nel and Mr. Charl Hertzog from the Department of Plant Production and Soil Science, University of Pretoria, South Africa for their technical assistance.