KAJIAN KETAHANAN VARIETAS KENTANG TERHADAP SERANGAN PENYAKIT Phytophthora infestans DI KABUPATEN KARO, SUMATERA UTARA - Loso Winarto; Lermansius Haloho (Jurnal Pengkajian dan Pengembangan Teknologi Pertanian, 2009)
The Study of Potato Variety Assessment Resistence for Phytophthora infestans Disease in District Karo, North Sumatra. Potate is a main potential commodity in  North Sumatra where the poduction was marketed to fulfill local and regional needs. This research was done in Cinta Rakyat Village, Simpang Empat Subdistrict, Karo Regency, North Sumatra which was located at 1,250 m above the sea level.  In this research four vatrieties were used; Granola, Atlantik, Kikondo, Margahayu and 0981-1085 Strains which were arranged by random Block Design and each treatment repeated 5 times. The distance between these plants was 30 cm x 80 cm, the plot measurement was 3m x 4 m (50 plants). The distance between each treatment was 50 cm, the distance between each repetition was 100 cm. To protect this plant from diseases several materials were used; 20 t/ha manure, 200 kg/ha urea, 400 kg/ha SP- 36, 200 kg/ha ZA, 150 kg/ha KCl.  Where as pest control was adjusted with the local condition. The research results after 70 days of plantation showed that the lowest intensity of Phytophthora  infestans disease was found  in Strains 0981-1085 (64.45%) treatment, where as the highest intensity was found in Granola variety (79.75%). The highest production was found in Strains 0981-1085 (31.89 t/ha) treatment, whereas Granola variety only reach 12,95 t/ha.  The R/C value was Granola (1), Margahayu (1.6), Atlantik (1.8), Kikondo (2.2) and 0981-1085 (2.5).Tanaman kentang merupakan salah satu komoditas unggulan dan menjadi sentra di Sumatera Utara, produknya dipasarkan untuk memenuhi kebutuhan lokal dan regional.  Kajian ini dilaksanakan di Desa Cinta Rakyat, Kabupaten Karo, Sumatera Utara, ketinggian 1250 m dpl.  Varietas kentang yang digunakan, yaitu: varietas Granola, Atlantik, Kikondo Margahayu dan Galur 0981-1085.  Menggunakan Rancangan Acak Kelompok, setiap perlakuan diulang 5 kali.  Jarak tanam kentang 30 cm x 80 cm, jarak antar perlakuan 50 cm.  Pupuk yang digunakan: pupuk kandang ayam 20 t/ha, Urea 200 kg/ha, SP-36 400 kg /ha, ZA 200 kg/ha, KCl 150 kg /ha.  Pengendalian hama disesuaikan dengan kebutuhan.  Hasil kajian menunjukkan bahwa tanaman pada umur 70 hari setelah tanam (hst), intensitas serangan Phytophthora infestans terendah terdapat pada perlakuan 0981-1085 (64,45%) sedangkan intensitas serangan tertinggi terdapat pada perlakuan Varietas Granola (79,53%).  Produksi tertinggi terdapat pada perlakuan Galur 0981-1085 (31,89 t/ha), sedang Varietas Granola hanya mencapai 12,95 t/ha.  Hasil perhitungan antara penerimaan dan pengeluaran (R/C) memberikan nilai secara berturut-turut Granola (1), Margahayu (1,6), Atlantik (1,8), Kikondo (2,2) dan Galur 0981-1085 (2,5).  Dengan demikian, tanaman kentang Galur 0981-1085 dan Kikondo layak untuk ditanam.