Toleransi Varietas Padi Hitam (Oryza sativa L. indica) pada Berbagai Tingkat Cekaman Kekeringan

ABSTRAK
Samyuni, 2015. S611308012. “Toleransi Varietas Padi Hitam (Oryza sativa L. indica) pada Berbagai Tingkat Cekaman Kekeringan”. Tesis. Pembimbing I: Prof. Dr. Ir. Edi Purwanto, M.Sc, dan Pembimbing II: Dr. Ir. Supriyadi, M.S. Program Pascasarjana, Program Studi Agronomi, Universitas Sebelas Maret Surakarta.

Penelitian bertujuan untuk mengukur tingkat ketahanan cekaman kekeringan pada tingkat kadar lengas tanah yang berbeda terhadap karakter pertumbuhan, perubahan biokimiawi dan hasil pada beberapa varietas padi hitam.
Penelitian dilaksanakan di Rumah Kaca Fakultas Pertanian UNS mulai bulan Mei sampai Nopember 2014. Penelitian dilaksanakan dengan rancangan acak lengkap faktorial terdiri atas 2 faktor dengan 3 ulangan. Faktor perlakuan I adalah kadar lengas pada 100, 80, 60 dan 40 persen kapasitas lapang. Faktor perlakuan II adalah macam varietas padi hitam terdiri atas 6 varietas yaitu Toraja, Jowo Melik, Wulung, Melik, Cempo Melik, dan Cempo Ireng.
Tolok ukur yang diamati adalah tinggi tanaman, jumlah anakan, jumlah anakan produktif, umur berbunga, panjang malai, jumlah gabah isi, jumlah gabah hampa, bobot 100 biji, bobot biji per rumpun, berat brangkasan kering, nisbah tajuk–akar, kandungan air relatif daun, tingkat menggulung dan mengering daun, kandungan amilosan dan kadar antosianin. Data dianalisis dengan sidik ragam dan dilanjutkan dengan uji beda Duncan; tinggi tanaman disajikan dalam diagram garis; kadar amilosa, antosianin, kepekaan terhadap kekeringan, dan kadar air relatif dilakukan analisis secara deskriptif.
Hasil penelitian menunjukkan bahwa peningkatan cekaman kekeringan mengakibatkan penurunan terhadap tinggi tanaman, jumlah anakan dan anakan produktif, kemunduran umur berbunga, jumlah gabah isi, bobot 100 biji, bobot biji per rumpun, berat kering brangkasan, nisbah tajuk–akar, kadar air relatif daun, serta meningkatkan jumlah gabah hampa. Varietas Wulung dan Cempo Melik pada 40% kapasitas lapang menghasilkan kandungan amilosa tinggi yaitu 20,76 dan 21,72 persen. Varietas Toraja pada cekaman kekeringan kandungan amilosanya sangat rendah yaitu 5 pesen, dan Jowo Melik kandungan amilosanya tinggi pada 80% kapasitas lapang sebesar 20,72 persen, dan sedang (18,26 dan 19,31 persen) pada 60 dan 40 % kapasitas lapang. Kandungan antosianin varietas Melik dan Cempo Melik meningkat pada 60% kapasitas lapang sebesar 2,5 persen dan 8,7 persen, serta Cempo Ireng pada 40% kapasitas lapang sebesar 5,7 persen. Penurunan kandungan antosianin terendah pada Toraja dan Wulung pada 80% kapasitas lapang sebesar 6,5 persen dan 18,8 persen, serta Jowo Melik pada 40% kapasitas lapang sebesar 12,5 persen. Penilaian kepekaan terhadap kekeringan dengan indikator menggulung dan mengeringnya daun padi hitam dapat dilakukan mulai kadar lengas 60% kapasitas lapang. Berdasarkan skor menggulung daun diperoleh varietas toleran pada Cempo Ireng, dan agak peka pada Toraja, Jowo Melik, Wulung, Melik dan Cempo Melik.

Kata Kunci: cekaman kekeringan, tingkat menggulung dan mengering daun, amilosa, antosianin

ABSTRACT
Samyuni, 2015. S611308012. “The Resistance of Black Rice (Oryza sativa L. indica) on Various Level of Drought Stress”. Thesis. The first adviser: Prof. Dr. Ir. Edi Purwanto, M.Sc., and the second adviser: Dr. Ir. Supriyadi, M.S. Agronomy Program of Graduate School, Sebelas Maret University of Surakarta.
The objectives of this research are to measure the level of drought stress on the different field capacity toward the plant growth character, biochemical change and the yield on various of black rice.
The research was conducted at the green house of Agriculture Faculty of Sebelas Maret University from May to November 2014. The research was carried out by applying completely randomized design consisted of two factors and three replication. The first treatment factor is the level of moisture content in 100, 80, 60 and 40 percent of field capacity. The second factor is the varieties, namely Toraja, Jowo Melik, Wulung, Melik, Cempo Melik, and Cempo Ireng.
The parameter observed in this research are the height of the plant, a number of tiller, productive tiller, anthesis, the panicle length, fertile grain, sterile grain, 100 grain weight, grain weight per clump, dry weight plant, shoot–root ratio, relative water content of leaf, leaf rolling and leaf drying, amylose and anthocyanin content. Data were analyzed by applying variance analysis and continued by applying Duncan test; the plant height was displayed in the form of line diagram; amylose content, anthocyanin content, drought sensitivity, and relative water content were analyzed descriptively.
The results indicate that the increase of the drought stress causes the decrease of plant height, a number of tiller, productive tiller, anthesis, fertile grain, sterile grain, 100 grain weight, grain weight per clump, dry weight plant, shoot–root ratio, relative water content of leaf, and increase the sterile grain. Wulung and Cempo Melik at 40% of field capacity yield high amylose content at the level of 20,76 percent and 21,72 percent. Toraja in drought stress has low amylose content, namely 5 percent, and Jowo Melik has high amylose content at 80% of field capacity, namely 20,72 percent. It has also intermediate amylose content (18,26 and 19,31 percent) at 60% and 40% of field capacity. The anthocyanin content of Melik and Cempo Melik increase at the level of 60% of field capacity, namely 2,5 percent and 8,7 percent. The increase of anthocyanin content is also indicated by Cempo Ireng at 40% of field capacity, namely 5,7 percent. The lowest decrease of anthocyanin content of Toraja and Wulung at 80% of field capacity is 6,5 percent and 18,8 percent. The decrease of anthocyanin content of Jowo Melik at 40% of field capacity is 12,5 percent. The drought sensitivity with leaf rolling and leaf drying can be measured from moisture content at 60% of field capacity. Based on the score of leaf rolling, Cempo Ireng is proved to be tolerant variety. Toraja, Jowo Melik, Wulung, Melik, Cempo Melik are moderately resistant.

Key words: the drought stress, the level of rolling and leaf drying, amylose, anthocyanin