Seleksi Tolerensi Tanaman Rumput Pakan Terhadap Cekaman Salinitas (Selection of Forage Grass Tolerance to Salinity Stress)

Abstract

Identitas dan analisis morfologi, fisiologi serta genetika ketahanan terhadap cekaman salinitas akan memberikan kontribusi nilai jangka panjang dalam penyediaan, pengembangan dan manipulai tanaman-tanaman yang toleran terhadap cekaman salinitas di Indonesia. Hal ini terkait bahwa di masa-masa yang akan dating lahan-lahan ekstensifikasi pertanian dihadapkan kepada masalah pemanfaatan lahan-lahan marjinal seperti tanah salin. Penelitian bertujuan untuk menyeleksi derajat toleransi sepuluh tanaman rumput pakan terhadap cekaman salinitas melalui pengamatan terhadap karakter morfologi, fisiologi dan genetika tanaman rumput pakan, dengan target khusus mendapatkan tanaman rumput pakan yang toleran terhadap cekaman salinitas. Percobaan diawali penentuan toksik untuk seleksi cekaman salinitas dengan menggunakan level 0, 100, 200, 300, 400 dan 500 nM NaCl. Selanjutnya dari satu titik level toksik yang dihasilkan dilakukan seleksi terhadap sepuluh tanaman rumput pakan dalam rancangan dasar acak lengkap Faktorial 5 ulangan. Faktor Pertama cekaman salinitas dan factor kedua tanaman rumput pakan. Kesimpulan hasil penelitian adalah (a) Bahwa level toksik untuk cekaman salinitas pada tanaman rumput pakan sebesar 100 mM Na dan (b) Derajat toleransi sepuluh tanaman rumput pakan dengan urutan indek derajat toleransinya (IDTK) sebagai berikut : Brachiaria brizantha (IDTK = 4,32, toleran), Brachiaria decumbens (IDTK = 4,07, toleran), Elusin indica (IDK = 3,80), Panicum muticum (IDTK = 3,80), Setaria sphacelata (IDTK = 3,69, toleran), Axonophus compressus (IDTK = 4,63, toleran), Panicum maximum (IDTK = 3,54, toleran) dan King Grass (IDTK = 3,54, toleran). ABSTRACT Identification and morphological analysis, physiology and genetic tolerance to salinity stress may give contribution value in providing, developing and manipulating crop that tolerance to salinity stress in Indonesia for long periods of time. This is connection with the future agricultural extention land that may facing problem in using marginal land such as saline soil. Experiment was aimed to select level of tolerance of ten forage grass on salinity stress through evaluation on morphological, physiological and genetic character of forage grass with special target to find out forage grass that tolerance to salinity stress. Experiment was initiated with determination of toxic level for selection of salinity stress by using level of 0, 100, 200, 300, 400 and 500 mM NaCl. Then, on the basic of one point of determined toxic levels of salinity stress, selection was conducted on ten of forage grass. Completely randomized design, factorial with 5 replication was used to arrange the experiment. The first factor was salinity stress and the second was forage grass. Experiment resulted that : Brachiaria brizantha (IDTK = 4,32, tolerance), Brachiaria decumbens (IDTK = 4,07, tolerance), Elusin indica (IDK = 3,80), Panicum muticum (IDTK = 3,80, tolerance), Setaria sphacelata (IDTK = 3,69, tolerance), Axonophus compressus (IDTK = 4,63, tolerance), Panicum maximum (IDTK = 3,54) dan King Grass (IDTK = 3,54, tolerance).