EFFECTS OF LATE BLIGHT RESISTANT POTATO CONTAINING RB GENE ON THE SOIL MICROBES, PESTS AND PLANT DISEASES Pengaruh Kentang Tahan Hawar Daun yang Mengandung Gen RB pada Mikroba Tanah, Hama, dan Penyakit Tanaman

Late blight caused by Phytophthora infestans is an important disease on potato. Several potato hybrids have been generated by crossing local varieties (Atlantic and Granola) with Katahdin SP951 which contains late blight resistance gene RB. Prior to release, these hybrids need to be evaluated for their environmental effects on non-target organisms and natural pests and diseases. The objectives of the study were to investigate the effect of LBR potato hybrids on beneficial soil microbes, pests and diseases. The trial was conducted in the confined field trial (CFT) in Lembang, West Java. The parental non-transgenic (NT) clones (Granola, Atlantic and Katahdin) and LBR hybrids (four clones of Atlantic x Katahdin SP951 hybrids; 10 clones of Granola x Katahdin SP951) were planted at a plant spacing of 30 cm x 70 cm. Fungicide applications were used as treatments (no spray, five and twenty times sprays). The experiment was arranged in a randomized completely block design with three replications. The parameters determined were populations of N 2 fixing and P solubilizing bacteria, soil C/N ratio as well as natural pests and diseases. The results showed that the transgenic LBR potato hybrids did not have negative effect on N fixing bacteria. The bacterial populations were around 10 10