Pengaruh Abu Sekam terhadap Pertumbuhan dan Ketahanan Tiga Varietas Padi Gogo Terinfeksi Rhizoctonia solani

The national rice demand always increases along with the increase of population. However, the production is still not able to meet the community requirement. One of the obstacles in rice cultivation is sheath blight disease by R. solani. Loss of rice yields due to sheath blight in Indonesia is 20-35%. The techniques for controlling sheath blight disease can be done through by inducing the resistance using silica (Si). One source of Si is husk ash with a content of 40.62% Si. The study was aimed to determine: 1) the effect of husk ash application to the growth of three upland rice varieties, and 2) the effect of husk ash application on the resistance of three upland rice infected with R. solani. This research was conducted from June to December 2020 at the Screenhouse, Laboratory of Plant Protection, Laboratory of Agronomy and Horticulture, Faculty of Agriculture, Jenderal Soedirman University, Purwokerto. A factorial randomized block design with two factors and three replications was used on the research. The first factor were the silica doses consists of 3 levels, namely P1 = without husk ash, P2 = husk ash with a dose of 5.6 g /polybag, and P3 = husk ash with a dose of 11.2 g /polybag. The second factor were the plant varieties which consisted of 3 different varieties, namely V1 = Situ Bagendit, V2 = Inpago Unsoed 1, and V3 = Parimas. The variables observed were incubation period, disease intensity, area under disease progress curve (AUDPC), infection rate, saponin content, tannin content, total phenol content, epidermal thickness, stomata density, plant height, number of leaves, number of tillers, number of productive tillers, panicle length, panicle weight, 100 seeds weight, plant wet weight and plant dry weight. The results showed that Si application rice husk ash at a dose of 11,2 g /polybag was able to increase the resistance of rice plants to the pathogen R. solani, which was able to suppress the incubation period of up to 3.9 days and the disease intensity was classified as moderate, as amount 31.44%. Rice husk ash was able increase various growth variables such as number of tillers, wet and dry weight of plants, the content of phenolic compounds and the thickness of the epidermis of rice leaves. However, treatment of husk ash at a dose of 5,6 and 11,2 g/polybag was not able to increase three varieties of gogo rice.Kebutuhan beras nasional selalu meningkat seiring dengan pertambahan jumlah penduduk, namun produksinya masih belum dapat memenuhi kebutuhan masyarakat. Salah satu kendala dalam budidaya tanaman padi adalah penyakit hawar pelepah daun yang disebabkan Rhizoctonia solani. Kehilangan hasil padi akibat penyakit hawar pelepah di Indonesia sebesar 20- 35%. Teknik pengendalian penyakit hawar pelepah padi dapat dilakukan melalui induksi ketahanan dengan menggunakan silika (Si). Salah satu sumber unsur Si adalah abu sekam dengan kandungan 40,62 % Si. Penelitian ini bertujuan untuk mengetahui: 1) pengaruh pemberian abu sekam terhadap pertumbuhan tiga varietas padi gogo, dan 2) pengaruh pemberian abu sekam terhadap ketahanan tiga padi gogo yang terinfeksi R. solani. Penelitian dilaksanakan pada bulan Juni - Desember 2020 di Screenhouse, Laboratorium Perlindungan Tanaman, Laboratorium Agronomi dan Hortikultura Fakultas Pertanian Universitas Jenderal Soedirman, Purwokerto. Penelitian menggunakan Rancangan Acak Kelompok Faktorial dengan dua faktor dan tiga ulangan. Faktor pertama yaitu pemberian dosis silika yang terdiri atas 3 macam taraf, yaitu P1= tanpa abu sekam, P2= abu sekam dosis 5,6 g/polybag, dan P3= abu sekam dosis 11,2 g/polybag. Faktor kedua yaitu varietas yang terdiri atas 3 macam varietas, yaitu V1= Situ Bagendit, V2= Inpago Unsoed 1, dan V3= Parimas. Variabel yang diamati yaitu masa inkubasi, intensitas penyakit, Area under disease progress curve (AUDPC), laju infeksi, kandungan saponin, kandungan tanin, kandungan fenol total, tebal epidermis, kerapatan stomata, tinggi tanaman, jumlah daun, jumlah anakan, jumlah anakan produktif, panjang malai, bobot malai, bobot 100 biji, bobot basah tanaman dan bobot kering tanaman. Hasil penelitian menunjukkan pemberian Si dari abu sekam padi dosis 11,2 g/polybag mampu meningkatkan ketahanan tanaman padi terhadap patogen R. solani, yaitu mampu menekan masa inkubasi hingga 3,9 hari dan intensitas penyakit yang tergolong sedang yaitu 31,44%. Abu sekam padi mampu meningkatkan berbagai macam variabel pertumbuhan seperti jumlah anakan, bobot basah dan bobotkering tanaman serta mampu meningkatkan kandungan senyawa fenolik dan ketebalan epidermis daun padi. Meskipun demikian, perlakuan abu sekam dosis 5,6 dan 11,2 g/polybag belum mampu meningkatkan hasil tiga varietas padi gogo