Judul: Pengaruh Suhu, pH, dan Konsentrasi terhadap Senyawa Bioaktif Antifungi Ralstonia pickettii dalam Menekan Pertumbuhan Rhizoctonia solani
Abstrak: 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.
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Judul: Keefektifan Formulasi Cair dan Pasta Ralstonia pickettii untuk Mengendalikan Penyakit Hawar Pelepah pada Padi
Abstrak: Rice is the most important food crop in Indonesia. Sheath blight disease is one of inhibiting factors in rice productivity improvement. Ralstonia pickettii has been reported as potential biological control agent of sheath blight. R. pickettii formulation technologies should be developed to increase its durability and effectiveness in suppressing sheath blight disease in the field. The purpose of this research was to determine the effectiveness of R. pickettii formulation in liquid and paste form. We formulated R. pickettii in liquid formulation by addition of glycerol to a final concentration of 25%. Paste formulation was made with composition of 44% talc, 3% xanthan gum, 3% molasses, 40% vegetable oil and 10% bacterial suspension. Efficacy test of both formulations was performed at concentrations of 5% and 10% in liquid formulation and 25 g/l and 50 g/l in paste formulation. Liquid formulation at both concentrations inhibited sheath blight disease at 5, 8, and 9 week after planting, whereas paste formulation with concentration of 50 g/l suppressed sheath blight disease at 5, 6, and 8 week after planting. However, paste formulation at concentration of 25 g/l only suppressed sheath blight disease at 8 WAP. Application of liquid and paste formulations did not affect plant height, number of tillers, and number of panicles of rice plants. Furthermore, application of liquid formulation at concentrations of 5% and 10% increased the fresh weight as much as 22% and 35%, respectively, and dry weight of grain as much as 26% and 32%, respectively. Otherwise, application of paste formulation at a concentration of 50 g/l increased the fresh weight of grain
Keyword: Rhizoctonia solani., paste formulation, liquid formulation, biological control agents, Ralstonia pickettii

Judul: Embriogenesis ikan buta (Astyanax fasciatus)
Abstrak: Ikan buta Astyanax fasciatus adalah spesies ikan unik dari famili Characidae yang menempati perairan dalam gua di Wilayah La Cueva Chica-San Luis Potasi-Mexico. Ikan ini memiliki mata yang tereduksi (Blind Cavefish) dan warna kulit merah muda, pucat serta mengkilap.
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