Pengaruh Suhu, pH, dan Konsentrasi terhadap Senyawa Bioaktif Antifungi Ralstonia pickettii dalam Menekan Pertumbuhan Rhizoctonia solani

Abstract

Rice sheath blight disease, caused by Rhizoctonia solani is an important disease on rice and loss of harvest up to 30%. Ralstonia pickettii was one of the biological agent from the group of bacteria which was able to suppress the growth of R. solani. In the laboratory scale, a filtrate of R. pickettii antifungal bioactive compound was able to suppress the growth of fungi up to 100%. Temperature and pH were the factors which were expected to influence the bioactive compound activity. The concentration of this antifungal bioactive filtrate also influenced the growth of R. solani inhibition. Therefore, this research was aimed to know the effectiveness of temperature, pH and concentration of R. pickettii to suppress the growth of R. solani. This research used factorial randomize complete design (RAL) which temperature: 25oC, 30oC and 40oC as the first factor and pH: 5, 6, 7, 8, and 9, were the second factor in three times of repetition. The result of this research showed that at temperature of 25oC and 35oC, antifungal bioactive compound were effective to suppress R. solani activity and pH did not show significant effect to bioactive compound activity. The concentration of 7.5 and 10 % was able to suppress R solani with 40% of the inhibition value.