KAJIAN GENETIK KADAR AMILOSA KARIOPSIS PADI BERBASIS INDIVIDU DENGAN METODE DESTRUKTIF DAN NONDESTRUKTIF

DIDI HARDJANTO, Dr. Ir. Taryono, M.Sc.

2015 | Disertasi | S3 Ilmu Pemuliaan Tanaman

Masyarakat dengan beragam wilayah lebih suka mengkonsumsi beras dengan tekstur tertentu. Dengan demikian kadar amilosa yang tepat harus diintegrasikan ke dalam kultivar baru untuk memuaskan konsumen. Tujuan dari penelitian ini adalah membandingkan hasil analisis kadar amilosa individual biji secara destruktif dan nondestruktif, memperoleh kombinasi persilangan yang prospektif untuk perbaikan rasa nasi yang pulen, memperoleh informasi tentang pola pewarisan genetika kadar amilosa individual biji destruktif dan nondestruktif. Bahan yang digunakan adalah kultivar padi ketan Lusi dan padi biasa kultivar IR-36, biji F1, F1R, F2, F2R, F3 dan F3R hasil persilangan antara Lusi X IR-36 dengan IR-36 X Lusi. Analisis amilosa dilakukan baik secara nondestruktif dan destruktif. Metode nondestruktif adalah gabungan antara teknik budidaya jaringan dengan cara menanam embrio pada medium aseptik dan bagian endospermnya dianalisis kadar amilosanya. Jumlah individual biji yang dianalisis kadar amilosanya untuk masing masing tetua dan F1 sebanyak 10 biji, untuk F2 dan F2R masing masing sebanyak 300 biji serta untuk F3 dan F3R masing masing sebanyak 300 biji. Penelitian dilakukan di laboratorium Balai Besar Penelitian Tanaman Padi Sukamandi untuk analisis kadar amilosa, di Laboraturium Budidaya Jaringan Fakultas Pertanian UGM untuk penanaman embrio, di laboratorium dan kebun percobaan PT. Agri Makmur Pertiwi untuk aklimatisasi sampai tanaman dipanen. Pelaksanaan penelitian dilakukan sejak bulan Pebruari 2012 sampai dengan bulan Pebruari 2013. Pengamatan morfologi tanaman tetua persilangan meliputi umur tanaman, tinggi tanaman, jumlah anakan produktif, panjang malai, jumlah butir/tanaman, hasil biji dan kadar amilosa. Pengamatan budidaya embrio meliputi jumlah akar, panjang akar dan tinggi plantlet. Pengamatan kadar amilosa dilakukan terhadap biji tetua, individual biji hasil persilangan (generasi F1, F2 dan F3). Hasil penelitian menunjukkan bahwa kadar amilosa padi Lusi baik menggunakan metode nondestruktif maupun destruktif tergolong sangat rendah dan padi IR-36 memiliki kadar amilosa tergolong tinggi. Hasil persilangan antara padi ketan Lusi dan padi biasa IR-36 dan persilangan resiproknya menunjukkan kadar amilosa biji F1 yang tergolong sedang (beras). Hasil perhitungan nisbah potensi hasil persilangan antara padi Lusi dengan padi IR-36 menunjukkan kadar amilosa individual dikendalikan oleh aksi gen dominan positif tidak sempurna dengan nilai rata rata F1 mendekati nilai tetua yang memiliki kadar amilosa tinggi. Kadar amilosa biji F2 mengikuti nisbah segregasi Mendel 15:1, yang berarti bahwa pewarisan kadar amilosa individual biji dikendalikan dua gen dominan duplikat dengan dua lokus dan dua alel per lokus. Distribusi frekuensi kadar amilosa biji F2 terlihat lebih jelas dan peluang untuk mendapatkan beras yang berkadar amilosa rendah sebagai penanda biokimia beras dengan rasa enak dan pulen lebih besar didapatkan pada metode nondestruktif.

Communities from diverse regions are more likely to consume rice with a particular type. Thus, the right amylose content has to be bred into new varieties to satisfy consumers. The purpose of this study is to compare the results of the analysis of amylose content of individual seeds using destructive and nondestructive method, to get prospective combination to improve taste of rice, to get information about genetic inheritance for amylose content. The research used two parents, i.e. Lusi a glutinuous rice variety having a very low amylose content and IR-36 a non glutinuous rice having a high amylose content as well as progeny F1, F1R, F2,F2R, F3, F3R which were crossed between Lusi X IR-36 and IR-36 X Lusi. The number of individual seeds whose amylose content was analyzed for each parent and F1 was ten, and for F2 and F2R there were 300 seeds respectivelly, and for F3 and F3R were also 300 seeds each. Research was conducted in the laboratory of rice research Sukamandi for amylose content analysis, in laboratory of Faculty of Agriculture for plant tissue culture, in laboratory and farm experiment PT. Agri Makmur Pertiwi for aclimatization until the crop harvested. The research had been conducted from February 2012 to February 2013. Morphological observation for parental include days to plant harvest, plant height, number of productive tillers, panicle length, number of grains per plant, seed yield and amylose content. Observations of embryo culture include root number, root length and height of plantlet. Observation of amylose content for the seeds of F1, F2 and F3 was based on destructive and nondestructive methods. The results showed that the amylose content both using destructive and non-destructive methods of glutinuous rice cultivar Lusi was relativelly very low, and cultivar IR-36 has a relativelly high amylose content. The result of a cross between rice (IR-36) and glutinuous rice (Lusi) and the reciprocal cross showed moderate amylose content. The potential ratio from the crossing of Lusi with IR-36 and reciprocal crosses showed that individual amylose content was controlled by partial dominant gene action (+) and was described by the average of F1 that tended to close to the average value of the parent with a high amylose content. The F2 generation seeds followed the Mendelian segregation ratio of 15 : 1, which meant that amylose content was controlled by two duplicate dominant genes. The distribution frequency of amylose content of F2 saw more clearly and the opportunities to get low amylose rice as biochemical marker for rice with good taste will be higher on nondestructive methods.

Kata Kunci : destruktif, nondestruktif, pola pewarisan, kultivar, aklimatisasi, padi ketan