Ankana Hanbunchong, Sompong Te-Chato, and Chaiyapoom Bunchasak

pp. 715 - 727

Abstract

The growth of Neck orange (Citrus reticulata Blanco) on seedling and cutting of trifoliate orange
hybrid rootstocks was studied at the Department of Plant Science, Faculty of Natural Resources, Prince of
Songkla University in order to select the appropriate rootstock. The stem cross section, growth characteristic and isozyme pattern of Neck orange scion were investigated. One-year-old seedlings and cuttings (both
with 0.3-0.4 mm stem diameter) of Troyer citrange, Swingle citrumelo and Neck orange were used as root
stock for grafting with Neck orange scions. The diameter of upper and lower graft union, number of branches
and leaves, height, root length, shoot and root dry weight and shoot: root dry weight ratio of grafted plants
were measured at 24 weeks after grafting. The results showed that the structure of stem cross section of
Troyer citrange and Neck orange i.e. the size of periderm, vascular bundle and pith, were similar to that of
Neck orange. The vascular bundle of Swingle citrumelo was larger than that of the two rootstocks. Troyer
citrange rootstock gave the best results in all growth parameters of Neck orange. The study of isozymes
recorded an extra locus (Est 3) of Swingle citrumelo rootstock occurred in Neck orange at 24 and 48 weeks
after grafting.