Pengujian Ketahanan Klon-klon Hasil Silangan Tanaman Kentang Transgenik dengan Nontransgenik terhadap Penyakit Hawar Daun Phytophthora infestans di Lapangan Uji Terbatas
Authors: Ambarwati Alberta Dinar , Herman Muhamad , Lisanto Edi , Suryaningsih Euis , Sofiari Eri 
Published: October 2016

STRAK. Tanaman kentang transgenik Katahdin event SP904 dan SP951 mengandung gen RB, yang diisolasi dari spesies liar kentang diploid Solanum bulbocastanum. Gen RB mempunyai ketahanan yang bersifat  durable dengan spektrum yang luas terhadap ras-ras Phytophthora  infestans di Amerika Serikat. Dalam perakitan tanaman kentang tahan penyakit hawar daun P. infestans di Indonesia, transgenik Katahdin dijadikan sebagai donor tahan dalam persilangan dengan varietas rentan Atlantik dan Granola. Klon-klon hasil silangan dianalisis secara molekuler mengandung gen RB. Penelitian dilakukan untuk menguji ketahanan klon-klon hasil silangan tanaman kentang transgenik dengan nontransgenik terhadap isolat P. infestans di lapangan uji terbatas (LUT) yang berlokasi di Balai Penelitian Tanaman Sayuran (Balitsa), Lembang dari bulan Oktober 2009 sampai dengan Maret 2010. Klon-klon yang diuji ialah 12 klon hasil silangan Atlantik x transgenik Katahdin SP904 (A); 15 klon hasil silangan Atlantik x transgenik Katahdin SP951 (B); 17 klon hasil silangan Granola x transgenik Katahdin SP904 (C); dan 20 klon hasil silangan Granola x transgenik Katahdin SP951 (D). Atlantik dan Granola digunakan sebagai kontrol rentan, sedangkan transgenik Katahdin sebagai kontrol tahan. Pengamatan dimulai ketika muncul gejala awal, yaitu pada 26, 32, 39, 46, dan 53 hari setelah tanam. Ketahanan tanaman semakin menurun dengan bertambahnya periode pengamatan, diikuti meningkatnya intensitas penyakit dan AUDPC. Semua klon yang diuji menunjukkan keragaman dalam ketahanan fenotipik terhadap hawar daun P. infestans. Klon-klon hasil silangan Atlantik x transgenik Katahdin SP951 mempunyai nilai AUDPC 697, yang hampir sama dengan transgenik Katahdin SP904 yaitu 698,5. Klon-klon Granola x transgenik Katahdin SP951 mempunyai nilai AUDPC  687,5 lebih kecil dibandingkan transgenik Katahdin SP904. Hasil penelitian ini juga menunjukkan bahwa klon-klon tersebut mempunyai ketahanan yang lebih tinggi dibandingkan transgenik Katahdin SP904. Pada pengamatan 46 hari setelah tanam atau 20 hari setelah infeksi diperoleh tiga klon tahan yaitu B49 (skor 7,5), C111 (skor 7,1), dan D26 (skor 7,3). Ketahanan ini lebih tinggi daripada transgenik Katahdin SP904 (skor 5,1) dan transgenik Katahdin SP951 (skor 6,4). <br /><br />ABSTRACT. Ambarwati, AD, Herman, M, Listanto, E, Suryaningsih, E and Sofiari, E 2012. Resistance Testing on Transgenic and Nontransgenic Potato Clones Against Late Blight Phytophthora  infestans in Confined Field Trial.  Transgenic potato Katahdin event SP904 and  SP951 containing RB gene, which were isolated from a wild diploid potato species, Solanum bulbocastanum. RB gene showed durable resistance with broad spectrum to all known races of  P. infestans in the USA. In development of  potato resistant to late blight P. infestans in Indonesia, Katahdin transgenic were used as a resistant donor and crossed with susceptible varieties i.e. Atlantic and Granola. Clones derived from the crossing were molecularly analyzed and had RB gene contain. Experiment was conducted to assess the resistance of the clones derived from crossing of Katahdin transgenic and nontransgenic to P. infestans in confined field trial (CFT), located at the Indonesian Vegetable Research Institute (IVEGRI), Lembang from October 2009 to March 2010. Several clones tested were 12 clones of Atlantic x Katahdin transgenic SP904 (A); 15 clones of Atlantic x Katahdin transgenic SP951 (B); 17 clones of Granola x Katahdin transgenic SP904 (C); and 20 clones of Granola x Katahdin transgenic SP951 (D). Atlantic and Granola were used as susceptible control whereas Katahdin transgenic as resistant control. Observation was started as late blight symptoms and detected at 26, 32, 39, 46, and 53 days after planting. Plant resistance decreases with increasing period of observation, followed by increasing disease intensity and AUDPC. All clones tested showed variation in phenotypic resistance to late blight P. infestans. Clones derived from crossing of Atlantic x Katahdin transgenic SP951 had AUDPC score 697 and almost similar to Katahdin transgenic SP904 (698.5). Clones derived from crossing of Granola x Katahdin transgenic SP951 had AUDPC score 687.5 and smaller than Katahdin transgenic SP904. The results also indicated that these clones had higher resistance than Katahdin transgenic SP904. Observation at 46 days after planting or 20 days after infection resulted three resistant clones i.e. B49 (score 7.5), C111 (score 7.1); and D26 (score 7.3).  This resistance was higher than Katahdin transgenic SP904 (score 5.1) and Katahdin transgenic SP951 (score 6.4). <br />