In vitro propagation of Amorphophallus konjac species in Vietnam for conservation and production

Abstract

Amorphophallus konjac is a species with high economic values; it is grown in some countries including China, Japan, and so on. Glucomannan in the tuber of A. konjac is a material for food industry and functional food processing. In Vietnam, A. konjac is found naturally growing in Ha Giang and Lao Cai provinces. The content of glucomannan in tubers of Vietnamese A. konjac is 44.97% (dry weight), nearly equal to that of the A. konjac variety in China with 45-55%. In this paper, we present the results of in vitro propagation of A. konjac species in Vietnam for conservation and production. The results showed that the top bud was sterilized effectively by using 60% sodium hypochlorite (NaOCl) in 12 minutes. The pure rate of in vitro samples was 100%, the regenerated rate of clean samples was 100%, and the time for budding was after 15 days. The best nutrient medium for bud regeneration of A. konjac was: MS + 2 mg/l BAP + 0.2 mg/l Kinetin + 8 g/l agar + 30 g/l sucrose, the average number of buds was 5.22 buds per sample, and the average height of bud was 3.84 cm with high quality. The best nutrient medium for rooting was 1/2 MS + 8 g/l agar + 14 g/l sucrose + 0.4 mg/l IBA + 1 g/l activated carbon, with the rooting rate of 100%, the average roots as 4.98 roots/shoot, the average length of roots as 2.67cm, after 7 days of culture. The most appropriate substrate for planting in vitro A. konjac was 50% soil + 30% sand + 20% rice hull ash, which provided the highest survival rates at 94.07%. After 4 weeks of planting, the trees grew and developed normally.