Uji Ketahanan 51 Galur Padi terhadap Penyakit Blast (Pyricularia oryzae) Ras 173
Blast Resistance Test On 51 Rice Strains Against Blast Disease (Pyricularia oryzae) race 173.
Abstract
As many as 51 strains rice hybrid from breeding program in Department of Agronomy and Horticulture, IPB had been already blast resistance tested by using injection method. The test rice plant with twice screening that first screening with three replicates and second screening as two replicates. First screening was begin with spore production of Pyricularia oryzae in oatmeal agar media washed once with sterile distilled water after 10 days incubation and harvested after n-UV radiation for 4 - 5 days to induce sporulation. Inoculations with Pyricularia oryzae were performed 20 days after sowing (have 4-5 leaves) by injection with spore suspension 105-106 spore/ml. The second screening must be done for tested 18 strain rice result from first screening with level resistance more than 90%. Seven strain resulted from first screening and second screening resistance level 100% are as follows: IPB107-F-5-1, IPB107-F-7-3, IPB113-F-2-2, IPB117-F-7-2, IPB140-F-2-1, IPB149-F-4, and IPB149-F-8. Identification of Pi-ta gene was carried out by Polymerase chain reaction (PCR) using two primer sets which amplified exon 1 and exon 2 region of the Pi-ta resistance gene. The result obtained in this identification shown that major blast resistance genes Pi-ta were detected in all of the strain from second screening, even the susceptible control plants (Kencana Bali). This results were different with the previous result shown Kencana Bali does not have Pi-ta resistance gene. This finding indicates that Pi-ta resistance gene has been lost from Kencana Bali due to deletion at the end terminal of exon2. Keyword : Strain rice, blast disease (Pyricularia oryzae), Pi-ta gene Padi hasil persilangan program pemuliaan padi Departemen Agronomi dan Hortikultura IPB sebanyak 51 galur telah berhasil diuji dengan menggunakan metode injeksi. Pengujian tanaman dilakukan dengan dua kali penapisan, penapisan I sebanyak tiga ulangan dan penapisan II sebanyak dua ulangan. Penapisan I dimulai dengan memproduksi spora Pyricularia oryzae di media oatmeal agar kemudian dicuci dengan akuades steril setelah diinkubasi selama 10 hari. Penyinaran n-UV dilakukan untuk menginduksi spora sehingga spora dapat dipanen. Suspensi spora dengan konsentrasi 105 – 106 spora/ml diinjeksi pada daun tanaman padi yang berumur 20 hari (± 4-5 daun). Penapisan II dilakukan untuk menguji 18 galur padi hasil penapisan I dengan tingkat ketahanan >90%. Sebanyak 7 galur diperoleh dari hasil penapisan I dan penapisan II dengan tingkat ketahanan 100% yaitu IPB107-F-5-1, IPB107-F-7-3, IPB113-F-2-2, IPB117-F-7-2, IPB140-F-2-1, IPB149-F-4, dan IPB149-F-8. Identifikasi gen ketahanan Pi-ta dilakukan dengan Polymerase chain reaction (PCR) menggunakan 2 pasang primer yaitu primer ekson1 yang mengamplifikasi daerah ekson 1 dan primer ekson2 yang mengamplifikasi daerah ekson 2 pada gen ketahanan Pi-ta. Hasil identifikasi didapatkan bahwa semua galur yang tahan mempunyai gen Pi-ta, termasuk kontrol peka (Kencana Bali). Hasil yang diperoleh berbeda dengan penelitian sebelumnya yang menunjukkan bahwa Kencana Bali tidak memiliki gen ketahanan Pi-ta. Hal tersebut diduga bahwa varietas Kencana Bali mengalami delesi pada bagian belakang ekson2. Kata kunci : galur padi, penyakit blas (Pyricularia oryzae), gen Pi-ta
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- UT - Biology [2078]