Influence of Rhizobacterial Inoculation on Growth of the Sweetpotato Cultivar

Sweetpotato (Ipomoea batatas L.) is the most important of local tuber crops in Malaysia. It is usually planted on marginal soils such as peat and sandy soils. Malaysian consumes a lot of sweetpotato and its production requires high fertilizer input, which can lead to increased production cost and environment problems. The use of bio-fertilizer and bioenhancer such as N₂ (nitrogen) fixing bacteria and beneficial micro-organism can reducechemical fertilizer applications and consequently lower production cost. The pot experiment was conducted to determine the influence of rhizobacterial isolates on the response of sweetpotato plant growth. A total of five rhizobacterial isolates capable of producing indole-3-acetic acid (IAA) were used. Four of the isolates were collected from sweetpotato rhizosphere and one isolate was imported. Cuttings of sweetpotato cultivars melaka and oren were planted in plasticpots containing alluvium soil. Cultures of the rhizobacterial isolates were inoculated at planting time, two and four weeks after planting. Plants were harvested 60 days after planting. The results showed that, three of isolates significantly increased the plant growth and the N, P, K, Ca and Mg uptake of sweetpotato cultivar.