Irrigation intervals affect physicochemical quality attributes and skin cracking in litchi fruit

Abstract

The influence of irrigation intervals on the physicochemical quality attributes and fruit cracking of litchi cultivars was investigated by irrigating 4 litchi cultivars at intervals of 3, 6, and 9 days. It was found that cultivars Gola and Bedana had the highest and lowest fruit weight (21.90 g and 14.31 g), pulp weight (16.478 g and 10.85 g), total soluble solids (22.16% and 16.37%), total sugars (21.22% and 15.28%), and fruit cracking (41.60% and 10.40%). While cultivar Gola also had the highest reducing sugars (18.01%) but the lowest nonreducing sugars (3.80%), cultivar Bedana had the lowest reducing sugars (5.68%) and the highest nonreducing sugars (10.02%). Similarly, cultivar Bedana had the highest skin strength (3.33 kg cm^{-2}) compared to the lowest (2.16 kg cm^{-2}) in cultivar Gola. The highest skin calcium content (4.916 mg 100 g^{-1} DW) was recorded in cultivar Surahi, while boron was the highest (0.112 mg 100 g^{-1} DW) in cultivar China. In contrast, Bedana had the lowest calcium (3.976 mg 100 g^{-1} DW) and boron (0.10 mg 100 g^{-1} DW) contents. The fruit and pulp weight decreased significantly with an irrigation interval of 9 days but the fruit cracking percentage increased significantly from 20.48% at a 3-day irrigation interval to 27.55% and 31.45% at irrigation intervals of 6 and 9 days, respectively. Increasing irrigation intervals decreased the skin strength and calcium content of the fruit but increased the reducing sugars and ion leakage from skin disks. The data suggest that both pulp and skin characteristics of litchi fruit may determine fruit cracking susceptibility and that increasing the irrigation intervals promotes the incidence of cracking.