Electronic Theses and Dissertation

Tanaman padi (Oryza sativa L.) merupakan komoditas tanaman pangan penghasil beras yang berperan sebagai makanan pokok masyarakat Indonesia. Produksi padi di Indonesia termasuk Aceh dalam lima tahun terakhir mengalami fluktuasi yang dipengaruhi oleh beberapa faktor, salah satunya adalah serangan penyakit hawar daun bakteri yang disebabkan Xanthomonas oryzae pv. oryzae (Xoo) dengan kehilangan hasil mencapai 80 %. Pengendalian penyakit hawar daun bakteri pada tanaman padi umumnya masih menggunakan pestisida sintetik yang berdampak negatif bagi lingkungan, kesehatan, tanaman, mikroorganisme, dan lainnya. Oleh sebab itu, diperlukan alternatif pengendalian yang relatif aman dan tidak merusak lingkungan misalnya dengan penggunaan bakteri endofit Paenibacillus polymyxa. Bakteri endofit P. polymyxa asal batang tanaman padi memiliki persentase daya hambat 51,54% terhadap Xoo secara in vitro. Penggunaan bakteri endofit untuk pengendalian penyakit hawar daun bakteri yang telah dilakukan oleh para peneliti memiliki beberapa metode aplikasi yang dapat menekan persentase serangan penyakit. Penelitian ini bertujuan untuk mengevaluasi efektivitas aplikasi bakteri endofit P. polymyxa untuk mengendalikan penyakit hawar daun bakteri pada tanaman padi.
Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) Non Faktorial yang terdiri dari delapan perlakuan dan tiga ulangan, setiap ulangan terdiri dari dua unit sehingga diperoleh 48 unit percobaan. Perlakuan aplikasi yang dilakukan dalam penelitian terdiri dari A0= kontrol (tanpa suspensi bakteri endofit), A1= Perendaman benih padi dalam suspensi bakteri P. polymyxa selama 13 jam, A2= Perendaman akar bibit tanaman padi umur 21 HSS dalam suspensi bakteri P. polymyxa selama 6 jam, A3= Penyemprotan daun tanaman padi umur 14, 28 dan 42 HST dengan suspensi bakteri P. polymyxa, A4= Perendaman benih + penyemprotan daun tanaman padi dengan suspensi bakteri P. polymyxa, A5= Perendaman akar bibit + penyemprotan daun tanaman padi dengan suspensi bakteri P. polymyxa, A6= Perendaman benih + perendaman akar bibit tanaman padi dalam suspensi bakteri P. polymyxa dan A7= Perendaman benih + perendaman akar bibit tanaman padi + penyemprotan daun tanaman padi dengan suspensi bakteri P. polymyxa. Setelah aplikasi bakteri endofit dan inokulasi Xoo, lalu diamati masa inkubasi, persentase kejadian penyakit, keparahan penyakit, hasil tanaman padi dan aktivitas enzim peroksidase.
Hasil penelitian menunjukkan bahwa rata-rata masa inkubasi paling lama yaitu 6,33 hari pada perlakuan A4 dan diikuti perlakuan A5 yaitu 4,83 hari. Kejadian penyakit hawar daun bakteri tertinggi pada perlakuan A0 sebesar 19,22% dan terendah 6,55% pada perlakuan A4 dengan keparahan penyakit tertinggi pada 28 hari setelah inokulasi (HSI) yaitu 43,33% pada perlakuan A0 dan terendah pada perlakuan A4 yaitu 28,75%. Rata-rata hasil tanaman padi tertinggi dijumpai pada perlakuan A4 yaitu 35,98 g dan terendah pada perlakuan A0 yaitu 9,49 g. Perlakuan A5 memiliki rerata aktivitas enzim peroksidase pada akar tertinggi yaitu 2,322 U/mg, rerata aktivitas enzim peroksidase pada batang tertinggi terjadi pada perlakuan A0 dan rerata aktivitas enzim peroksidase pada daun tertinggi ditemukan pada perlakuan A2 yaitu 1,504 U/mg. Aplikasi bakteri endofit P. polymyxa dengan perendaman benih dan penyemprotan daun tanaman padi efektif untuk mengendalikan penyakit hawar daun bakteri karena memiliki rata-rata masa inkubasi lebih lama, persentase kejadian dan keparahan penyakit lebih rendah dan hasil tanaman lebih tinggi dibandingkan perlakuan lainnya.

Rice (Oryza sativa L.) is a rice-producing food crop commodity that serves as the staple food of the Indonesian people. Rice production in Indonesia including Aceh in the last five years has fluctuated which is influenced by several factors, one of which is the attack of bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae (Xoo) with yield losses reaching 80%. Control of bacterial leaf blight in rice plants generally still uses synthetic pesticides that have a negative impact on the environment, health, plants, microorganisms, and others. Therefore, an alternative control that is relatively safe and does not damage the environment is needed, for example by using the endophytic bacterium Paenibacillus polymyxa. Endophytic bacteria P. polymyxa from rice stems have a 51.54% inhibition percentage against Xoo in vitro. The use of endophytic bacteria to control bacterial leaf blight that has been done by researchers has several application methods that can reduce the percentage of disease attack. This study aims to evaluate the effectiveness of the application of endophytic bacteria P. polymyxa to control bacterial leaf blight in rice plants. This study used a Non-Factorial Completely Randomized Design (CRD) consisting of eight treatments and three replications, each replication consisting of two units so that 48 experimental units were obtained. The application treatments carried out in the study consisted of A0 = control (without endophytic bacterial suspension), A1 = Soaking rice seeds in a suspension of P. polymyxa bacteria for 13 hours, A2 = Soaking the roots of rice seedlings aged 21 HSS in a suspension of P. polymyxa bacteria for 6 hours, A3 = Spraying the leaves of rice plants aged 14, 28 and 42 HST with a suspension of P. polymyxa bacteria, A4= Soaking seeds + spraying the leaves with P. polymyxa bacteria suspension, A5= Soaking the roots + spraying the leaves with P. polymyxa bacteria suspension, A6= Soaking seeds + soaking the roots in P. polymyxa bacteria suspension and A7= Soaking seeds + soaking the roots + spraying the leaves with P. polymyxa bacteria suspension. After endophytic bacteria application and Xoo inoculation, the incubation period, percentage of disease incidence, disease severity, rice yield and peroxidase enzyme activity were observed. The results showed that the longest average incubation period was 6.33 days in treatment A4 and followed by treatment A5 which was 4.83 days. The incidence of bacterial leaf blight was highest in treatment A0 at 19.22% and lowest at 6.55% in treatment A4 with the highest disease severity at 28 days after inoculation (DAI) which was 43.33% in treatment A0 and lowest in treatment A4 which was 28.75%. The highest average yield of rice plants was found in treatment A4 which was 35.98 g and the lowest in treatment A0 which was 9.49 g. Treatment A5 had the highest average peroxidase enzyme activity in roots which was 2.322 U/mg, the highest average peroxidase enzyme activity in stems occurred in treatment A0 and the highest average peroxidase enzyme activity in leaves was found in treatment A2 which was 1.504 U/mg. The application of endophytic bacteria P. polymyxa by soaking seeds and spraying the leaves of rice plants is effective for controlling bacterial leaf blight because it has a longer average incubation period, a lower percentage of disease incidence and severity and higher plant yields than other treatments.