Effect of Plastic Film Mulching on Fruit Quality of Citrus grandis cv. 'Hongroumiyou' and 'Sanhongmiyou'

Plastic film mulching (PFM) around fruit trees could effectively improve fruit quality by promoting fruit coloration and sugar accumulation. 'Hongroumiyou' and 'Sanhongmiyou' are mutated from Citrus grandis cv. 'Guanximiyou' possessing attractive appearance, rich nutritional ingredients. When they are introduced into Sichuan Province, the fruits revealed lower sugar accumulation and higher acid content than that in Fujian Province. We compared the fruit quality by mulching at 55, 85, 115, 145, 175 days after flowering. The results showed that mulch treatment had no significant effect on the external quality of 'Hongroumiyou' and 'Sanhongmiyou'. While it could effectively improve the internal fruit quality, including promotion of total soluble solid and vitamin C, and decrease of total acid. The best effect on the improvement of fruit quality was mulched at 115 days after flowering for 'Hongroumiyou' and 145 days after flowering for 'Sanhongmiyou'. In addition, mulching cultivation also avoided tree death resulted from the rootrot atrophy because of a long-term flooding. It is important to promote film mulching cultivation in the pummelo production in Sichuan Province.