Early Performance of Duong Mandarin (Citrus reticulata Blanco) on Three Rootstock under Acid Sulfate Soil Fields at Mekong Delta of Vietnam

Abstract About 1.6 billion hectare area of acid sulfate soils is at Mekong Delta of Vietnam, and Duong mandarin fruits are valued for the fresh market due to the easy peeling, attractive flavor, and health and nutritional properties; thereby, the investigation on early performance of Duong mandarin on three rootstock under acid sulfate soil fields (pH below 4) at Mekong Delta of Vietnam was undertaken from 2009 to 2012 for determination of the most promising scion stock combination of Duong mandarin, which introduced to growers for expanding citrus production to increase in income of farmers, and helping to use the sustainable and efficient land resource at acid sulfate soil region of Mekong Delta. Primary results showed that Duong mandarin grafted on Mat orange, Tau lemon and Carrizo citrange were significant differenence in vegetative parameters, fruit yield and quality. It proved that Duong mandarin trees grafted on Tau lemon were better growth and development on acid sulfate soil fields with below 4 pH in soil and water suspension of 1:2.5 ratio) as compared to those grafted on Mat orange and Carrizo citrange rootstocks; whereby, that induced trees with 171.48 cm height, 6.65 m3 canopy volume and 51.84 mm trunk diameter, 1.08 scion/ stock ratio in third year after growing. Moreover, Duong mandarin trees grafted on Tau lemon were with spreading growth performance. In regarding to fruit yield and quality, Duong mandarin trees grafted on Tau lemon produced highest fruit yield of 9.21 kg per tree per year in third year after planting, and fruit with 115.30g weight, 8.85 brix juice, thinner and somewhat easy peel rind.