Mutation breeding using gamma irradiation is one of the alternative ways to increase the variability and productivity of Guinea grass (Panicum maximum cv Purple guinea). The aimed of the study was to determine the dosage of gamma irradiation and morphological characters for highyielding of the putative mutant of guinea grass. The Guinea grass seeds was irradiated by gammaray. The treatment was 8 doses of gamma irradiation and control (non-irradiated). The treatment was arranged in a randomized complete block design (RCBD) with 3 replications. The study was conducted for 3 generations, which were mutants 1 (M1), mutant 1 vegetative 1 (M1V1), and mutant 1 vegetative 2 (M1V2). The results showed that the gamma irradiation dose affected variables observed. The variables affected in M1 were fresh and dry weights of shoot, the number of tillers, and the length of the leaves. Whereas in the populations of M1V1 and M1V2, almost all characters were influenced by gamma irradiation, except stem diameter, length of internode, and leaf length. Gamma irradiation doses of 175 x 2 Gy, 250 Gy and 350 Gy in M1V1 and 100 x 2 Gy, 150x2 Gy and 175 x 2 Gy in M1V2 produced the high number of tillers, fresh and dry shoot weights. Heritability value and GCV of number of tillers, fresh and dry weight of shoot were high for M1V1 and M1V2 populations. These results indicated that gamma-ray irradiation can be applied to increase productivity and genetic variability of Guinea grass. The highest forage production was obtained at a dose of 100 x 2 Gy, which was 625 g/plant.

<em></em><p class="abstrak2">The induction mutation using gamma rays is one way to increase the diversity of Bengggala grass (<em>Panicum maximum</em>). Diversity is the main base in selecting to produce varieties of Benggala grass on acid land. The aim of this study is to know the morphological character and genetic diversity of grass that received gamma rays. The research was conducted in the Tenjo district, Bogor which has pH 4.9-5.5 and the content of Al-dd 2.26 c mol/kg with Al saturation of 10.68%. The study started by looking for Benggala grass radio sensitivity, then from radio sensitivity determined radiation treatment dose of 200 Gy, 250 Gy, 300 Gy and 350 Gy. Treatment of radiation dose is acute and fractionated, so there are 8 treatment doses plus control (plants without radiation). The variables measured were plant height, stem height, stem diameter, length of segment, leaf length, leaf width, fresh weight, dry weight, and number of tillers. The results showed that the radio sensitivity of Benggala grass produced in the form of lethal doses (LD) LD 20 and LD50 is 176.83 Gy and 358.23 Gy. By the mathematical equation: Y = 44.22 + 45.91 X Cos (0.0042x -0.07). The morphological character of M1 shows that the radiation dose affects the measured variable. 300 Gy fractionated radiation dose (150 Gy x 2) results in higher fresh weight of the plant. While in the generation of M1V1 radiation dose of 250 Gy produces high fresh forage weight. Medium to high heritability with GVC value (criteria of coefficient of genetic variability) is high enough until high is obtained on the character of the number of tillers, fresh weight and dry weight. So it is possible to do next selection on these three characters.</p><strong>Key Words</strong>: <em>Panicum maximum</em>, Irradiation, Mutation, Morfology, Genetic Variability<em><br /></em>

No abstract

The objective of this study was to determine the agronomic diversity of gamma-ray at 50 Gray dose   during the phase of embryogenetic callus in napier grass cv Taiwan. This research used a randomized blok design (RBD) of gamma-ray and without radiation elephant grasses (P. purpureum cv Taiwan). There were 51 numbers in irradiated elephant grass, each number three replicated and five plant per number each. Without irradiation control used elephant grass (P. purpureum cv Taiwan); there were 10 clumps in one block and each line number had been repeated three times. Gamma radiation showed no impact on plant height and stem weight (dry weight) at P>0.05, but had a significant effect on number of tillers, leaf length, leaf width, total weight, fresh weight, leaf (dry weight), weight of stem (fresh weight). Gamma ray irradiation selection does not have to generate high output but can be developed on sub optimal soil or extreme weather conditions such as tolerant felling, which requires less high plant. Key words:        diversity, forage, irradiation

Rumput benggala merupakan tanaman pakan ternak (TPT) yang banyak digunakan oleh peternak di Indonesia. Pengembangan budidaya TPT, selalu diarahkan pada lahan sub optimal. Salah satu lahan suboptimal yang luas keberadaannya adalah lahan kering masam. Tujuan penelitian ini adalah untuk melihat karakter morfologi dan produktivitas kultivar rumput benggala di tanah masam. Penelitian dilakukan di rumah kaca Balai Penelitian Ternak Ciawi, menggunakan 3 kultivar rumput benggala (kultivar Petrie, Gatton dan Natsuyutaka). Kultivar tersebut ditanam di 2 jenis tanah yaitu tanah masam dan tidak masam pada pot berdiameter 40 cm. Rancangan penelitian menggunakan rancangan acak lengkap, dengan 10 ulangan. Peubah yang diamati adalah karakter morfologi, umur berbunga, produksi biji dan produksi hijauan. Hasil penelitian menunjukan bahwa karakter morfologi seperti panjang dan, panjang ruas, diameter batang, panjang kuntum bunga lebih dipengaruhi oleh kultivar jika dibandingkan jenis tanah. Sedangkan produktivitas rumput lebih dipengaruhi jenis tanah, produktivitas tanaman menurun pada tanah masam jika dibandingkan di tanah tidak masam. Semua kultivar rumput benggala yang diuji produktivitasnya menurun pada tanah masam, menunjukkan bahwa ketiga kultivar yang diuji tidak toleran pada lahan masam. Sehingga perlu dilakukan kegiatan pemuliaan untuk memperoleh rumput benggala toleran masam. Kata kunci: produksi, suboptimal, tanaman pakan