Somchai Chuan-udom and Mongkol Sae-Lim

pp. 515 - 530

Abstract

The influence of some citrus rootstock species on yield, fruit quality and compatible characteristics of Necked orange (Citrus reticulata Blanco cv. Necked orange) and Shogun (Citrus reticulata Blanco cv. Shogun) was investigated at the Department of Plant Science, Faculty of Natural Resources, Prince of Songkla University during January, 2003 to October, 2004. Eighty-eight of three-year-old Necked orange and Shogun
grafted onto 11 species of citrus rootstocks were raised in 35 litre pot. Complete randomized factorial design was used for evaluating the two factors, scions and rootstocks. The vegetative growth: upper and lower of
trunk diameter, tree height, canopy volume and leaf area; the foliar nutrient: nitrogen (N), phosphorus (P), potassium (K), total non-structural carbohydrates (TNC) and C/N ratio; flowering; fruit-set and fruit qualities were determined and analysed. Furthermore, the graft compatibility between stock and scion was also evaluated by the esterase isozymes technique. It was found that Necked orange grafted onto most of the rootstocks showed higher range of upper and lower trunk diameter and leaf area than that of Shogun. Both of the scions on rough lemon and volkamer lemon gave higher vegetative growth characteristics than on the other roostock species. Necked orange grafted onto Cleopatra mandarin, Swingle citrumelo, Volkamer lemon
and Mawo rootstock had 5 times the flowering and fruit-set while Shogun grafted on Troyer citrange had 7 times the flowering and fruit-set. There was no significant difference on the foliar nutrient between scions and rootstocks except the foliar TNC of necked orange and Shogun on Manaao-khwaai (34.86%). Necked orange and Shogun grafted on Troyer citrange gave the highest number of fruits/tree (20.6 and 31.6 fruits/tree) and fruit weight/tree (3,906 g/tree and 5,114 g/tree respectively). Necked orange grafted onto Rough lemon showed the highest rind thickness (0.559 cm) while Shogun grafted onto Cleopatra mandarin showed 0.275 cm rind thickness. Necked orange grafted on Troyer citrange and Mawo and Shogun grafted on Troyer
citrange and Volkamer lemon gave the highest TSS: TA ratio. The esterase enzyme pattern of necked orange grafted on Manaao-khwaai was changed and most of the rootstock species affected the esterase enzyme
activities of Shogun.