| Popis: |
Fruit cracking is a serious problem in litchi, which occurs mainly in the field and causes significant losses of 5-90% of economic yield and will intensify in the future due to climate change. It coincides with high temperature (35-40°C) and low relative humidity (60%). There are several factors; genetics/varietal characteristics, leaf characteristics, skin thickness and spongy layers, number of tubers, fruit pressure, fruit chemical composition, fruit position, soil management, soil moisture, light, micronutrient deficiency, mechanical damage, enzymatic activities, hormonal balance and molecular aspect affect fruit cracking in litchi. Cracks in the skin can be longitudinal or horizontal. Fruit cracking occurs in early cultivars with sunburn, while in late cultivars it occurs without sunburn. Cracking occurs when the pith develops and puts pressure on the inactively growing pericarp. Thus, a balance between the turgor pressure from the expanding flesh and the mechanical structure, and elasticity of the pericarp is essential to prevent fruit cracking. Fruit cracking can be controlled by soil moisture treatment, mulching, bagging fruit bunches, shade netting, application of plant growth regulators and nutrients such as calcium nitrate (0.5-1%), borax (0.4-0.8%), Zn (0.4%), GA3 (10 ppm) and growing cultivars resistant to cracking. KEYWORDS: Fruit cracking, Litchi, Pericarp, Temperature, Bagging, Mulching |
