Pengaruh Pengaturan Populasi dan Ukuran Lempengan Rumput Manila (Zoysia Matrella (L.) Merr) terhadap Pertumbuhan dan Perkembangannya

Zoysia matrella (L.) Merr. is a widely used ornamental grass, particularly in home and landscape gardens, because of its soft appearance and high quality. One of main problem is its low growth rate. Therefore, specific cultural techniques are required to accelerate its growth while maintaining its attractive appearance. This experiment was aimed to study the effect of sod size and planting distance of Zoysia mairella. on grass growth and development. The experiment was conducted at the IPB experimental station at Darmaga IV, Bogor, for 8 months and was completed in August 1990. The trials used a split plot design with 2 factors and 3 replications. Treatment consisted of 2 planting distances i.e. (20 x 20) cm and (25 x 25) cm, and 4 sod sizes, i.e. (2 x 2) cm, (5 x 5) cm, (8 x 8) cm, and (10 x 10) cm. The variables observed were percentage of coverage, rate of coverage, quality of leaf color quality of appearance, and uniformity of growth. The results indicated that population density did not significantly affect variables observed except for uniformity of growth. Hence, the larger the sod size, the higher its rate of coverage and the more uniform its appearance, but the lower its quality of appearance. Statistically, the sod size significantly affected the percentage of coverage, rate of coverage, quality of appearance, and uniformity of growt

Evaluasi Keragaman Fenotipik Pisang Cv. Ampyang Hasil Iradiasi Sinar Gamma di Rumah Kaca

ABSTRACTBanana  and plantain   are  important  for  food  security.   Increase  of genetic variability  is  difficult because  most  of  edible  bananas  are  triploid,  sterile and  parthenocarpy.   Therefore,  breeding  through convetional  method are difficult.  The objective of  this research were to evaluate  phenotypic variation of banana  cv.  Ampyang  (Musa  acuminata,  AAA,  subgroup  non-Cavendish) regenerated  from  in  vitro induced  mutation  by  gamma  irradiation  in  a greenhouse.   The  objectives  of  this  research  were  to characterize and evaluate phenotypic diversity of banana cv. Ampyang plant, in vi tro regenerated from gamma irradiated plantlet in a greenhouse. The phenotypes (both quantitative and qualitative characters) were evaluated when the plants were at six months after acclimatization. Result indicated banana plant sregenerated from gamma irradiated explants exhibited lower plant height, shorter leaf, and leaf length by leaf width ratio than from non-irradiated ones. Population of banana cv. Ampyang gamma irradiated at30, 40, 45 and 50 Gy showed broader variation in  qualitative characters than those  treated with 0 Gy. Banana cv. Ampyang originated from explants treated with 0 Gy showed similar stomatal density than those from explants treated with 45 and 50 Gy. On the other hand, those originated from explants treated with 20, 25, 30 or 40 Gy showed lower stomatal densities than those treated with 0 Gy.  The results have demonstrated  that  mutation  breeding  with  in vitro  technique could produce morphological changes as well as increase in variability of  quantitative traits.  A number of these  parameters were supposed to be applicable for characterization of variation in other banana cultivars.Key words:  Musa acuminata (AAA), stomata density, doses of gamma irradiationABSTRAKPisang  penting  untuk  keamanan  pangan.   Peningkatan keragaman  genetik   pada  pisang  sulit dilakukan  karena  sebagian  besar  pisang  yang  dapat dimakan  bersifat  triploid,  steril  dan  partenokarpi.Oleh sebab itu, pemuliaan tanaman secara konvensional sulit dilakukan. Tujuan penelitian ini ialah untuk mengevaluasi variasi fenotipik pisang cv. Ampyang (Musa acuminata, AAA, subgroup non-Cavendish)yang diregenerasikan dari kultur in vitro dan diinduksi mutasi dengan sinar gamma.  Fenotipe (karakter kualitatif dan kuantitatif) dievaluasi ketika tanaman berumur 6 bulan setelah aklimatisasi. Hasil penelitian menunjukkan  bahwa  tanaman  pisang  yang  diregenerasikan dari  eksplan  yang  diiradiasi  sinar  gamma memiliki tinggi tanaman yang lebih rendah, daun yang lebih pendek, dan rasio panjang dan lebar daun yang lebih  rendah  dibanding  tanaman  non-iradiasi.  Populasi  pisang  cv. Ampyang hasil  iradiasi  sinar gamma  30, 40, 45  dan  50 Gy  menunjukkan variasi yang lebih lebar dalam karakter kualitatif dibanding tanaman kontrol (0 Gy). Pisang cv. Ampyang asal eksplan kontrol (0  Gy) menunjukkan densitas stomata yang sama dengan tanaman eksplan yang diiradiasi sinar gamma 45 dan 50 Gy. Tanaman yang berasal dari eksplan yang diiradiasi sinar gamma  20, 25, 30 or 40 Gy  menunjukkan densitas stomata yang lebih rendah dari tanaman kontrol (0 Gy).  Hasil penelitian ini menunjukkan bahwa pemuliaan mutasi dengan teknik in vitro dapat menghasilkan perubahan morfologi dan juga peningkatan variabilitas sifat kuantitatif dan  sejumlah  parameter  tersebut diharapkan  dapat  diaplikasikan  untuk  karakterisasi  variasi  kultivar pisang lainnya.Kata kunci : Musa acuminata (AAA), densitas stomata, dosis iradiasi sinar gamm