Karakterisasi dan Seleksi In Vitro Klon Jeruk Siam Kintamani Hasil Radiasi Sinar Gamma terhadap Ketahanan Penyakit Huanglongbing

Abstract

Jeruk Siam Kintamani (JSK) merupakan salah satu varietas unggul di Indonesia. Sampai saat ini, belum ditemukan varietas jeruk tahan Huanglongbing yang dilepas secara komersial. Persilangan tanaman untuk mendapatkan varietas yang tahan melalui persilangan konvensional tidak memungkinkan karena ketiadaan plasma nutfah yang memiliki gen ketahanan Huanglongbing. Metode alternatif untuk memperoleh kultivar tahan adalah induksi mutasi yang dikombinasikan dengan seleksi in vitro. Penelitian ini bertujuan mengkarakterisasi klon JSK hasil radiasi sinar gamma dan seleksi in vitro terhadap ketahanan Huanglongbing. Penelitian menggunakan Rancangan Acak Lengkap 1 faktor, yaitu JSK hasil radiasi sinar gamma, dengan 4 taraf perlakuan, yaitu klon 4,5 Gy, klon 5,0 Gy, klon 5,5 Gy, dan klon tanpa radiasi dengan masing-masing taraf 9 ulangan. Analisis menggunakan analisis ragam dengan uji lanjut BNJ taraf 5%. Seleksi dilakukan terhadap klon JSK hasil radiasi, klon JSK tanpa radiasi, dan jeruk nipis sebagai kontrol. Induksi mutasi berhasil meningkatkan keragaman terhadap karakter morfologi JSK. Seleksi in vitro berhasil menyeleksi keragaman akibat mutasi yang disebabkan radiasi sinar gamma terhadap ketahanan Huanglongbing. Dari hasil seleksi, dihasilkan 3 tanaman tahan dan 1 tanaman toleran Huanglongbing. Perlu dilakukan uji lanjut untuk mengonfirmasi ketahanan tanaman tersebut di rumah kaca.

Kintamani Tangerine (JSK) is one of the superior varieties in Indonesia. Huanglongbing-resistant citrus varieties have not been released commercially until now. Conventional crossbreeding is not possible due to the absence of Huanglongbing resistance genes germplasm. Alternative method to obtain resistance cultivars is mutation induction combined with in vitro selection. This study aimed to characterize the clone of JSK from gamma irradiation treatment and select it for Huanglongbing resistance through in vitro selection. The experimental design used was a completely randomized design with 1 factor, JSK from gamma irradiation treatment, 4 treatment levels, which are 4.5 Gy clone, 5.0 Gy clone, 5.5 Gy clone, and without radiation clone with 9 replications each. This study used an analysis of variance with the Tukey HSD follow-up test at 5% level. The selection was carried out on clone of JSK from gamma irradiation treatment, clone of JSK without radiation, and lime as a control. Mutation induction resulted variation to the morphological characters of the JSK. In vitro selection was able to select the clone of Huanglongbing resistance. The selection resulted 3 Huanglongbing-resistant plants and 1 Huanglongbing-tolerant plant. Further tests are needed to confirm its resistance in the greenhouse.