Judul: Seed treatment improved seed quality, seed production and controlled downey mildew disease on sweet corn
Abstrak: Downy mildew is a major disease in sweet corn caused by Peronosclerospora maydis, a seedborne pathogen. An effort to get successfully field production is by using high quality seeds. Seed quality consists of physical, physiological, genetical, and pathological (seed health) quality. The aims of this research were to evaluate the effectiveness of seed treatment using synthetic fungicide and biological agent to control downey mildew disease, to improve plant growth, seed production, and seed quality of harvested sweet corn. This study consistsed of 3 stages: pre experiment, experiment 1, and experiment 2. In pre experiment, the compatibility among the biological agents, the compatibility between biological agents and synthetic fungicides, phytotoxicity and hypersensitivity were tested. The optimum matriconditioning ratio and the time of conditioning were also evaluated. All the pre experiment activities were conducted in laboratory. Experiment 1 was done to evaluate the effect of seed treatments on seed physiological quality, disease incidence, and plant growth of sweet corn. Seed physiological quality test was conducted in laboratory, whereas disease incidence and plant growth were done in plastic house. Experiment 1 was conducted using completely randomized design with one factor which was seed treatment. The best result of experiment 1 was used as seed treatment in experiment 2 which was conducted in the field. Split plot design with two factors was used in this experiment, sweet corn line as main plot and seed treatment as sub plot. Experiment 2 was conducted to evaluate the effect of seed treatments on disease incidence, plant growth and seed production. The result of compatibility test showed that Bacillus megaterium did not inhibit growth of Brevibacillus laterosporus, and vice versa. The growth of biological agents (B. megaterium and B. laterosporus) were not inhibited by synthetic fungicide. Hypersensitivity test of B. megaterium and B. laterosporus isolates showed negative result. The ratio of seed : burned rice hull (100 mesh): solvent = 3: 0.5: 1 and 24 hours conditioning at 20 0C was optimum, resulting the highest seed physiological quality. In experiment 1, the best vigor index and germination speed resulted from B. laterosporus biological agent treatment. The lowest disease incidence (64%) was by synthetic fungicide treatment without matriconditioning, whereas control and all non fungicide treatments produced 100% disease incidence. All treatments except matriconditioning and control increased plant growth. Matriconditioning + mixture of synthetic fungicide + B. laterosporus was the best seed treatment in increasing plant dry weight. In experiment 2, line 07 was more resistant to downy mildew attack. Line 07 also produced better growth than line 06. Seeds of line 07 applied with matriconditioning + mixture of fungicide treatment + B. laterosporus resulted the highest ear weight per plant (53 g). Application of all seed treatments on line 07 were not able to increase the quality of harvested seed, but matriconditioning + mixture of synthetic fungicide + B. laterosporus on line 06 was able to increase physiological quality of harvested seed.
Keyword: Bacillus megaterium, Brevibacillus laterosporus, downey mildew, matriconditioning, Peronosclerospora maydis

Judul: Analisis Daya Gabung dan Heterosis Ketahanan terhadap Penyakit Bulai (Peronosclerospora maydis) dan Daya Hasil Jagung Manis
Abstrak: Zea mays var. saccharata Sturt. more popular called sweet corn was horticulture crop that have high economic value. This experiment consist of three experiments. First experiment aimed to evaluate 74 sweet corn lines of downy mildew resistance. The result showed that 74 sweet corn lines, had different resistance to downy mildew, 18 lines belonging to medium susceptible and 56 lines belonging to susceptible. Seven lines sweet corn selected with different response to downy mildew disease, the lines were DMST531 (B) 29.95%, DMSG781 (D) 37.00%, DMSC499 (A) 52.80%, DMSS491 (F) 59.15%, DMSE711 (E) 76.65%, DMSK5 (C) 84.35% dan DMSF11 (G) 88.50%. Clustering based on coefficient similiarity 81%, resulted in four cluster, one was lines DMST531, DMSF11, DMSG781 and DMSS491, second was line DMSC499, third was line DMSK5 and fourth was line DMSE711. Second experiment studied combining ability and heterosis for downy mildew (P. maydis) resistance in sweet corn. General combining ability (GCA) and specific combining ability (SCA) values were significant for disease resistant but the resiprocal effect was not significant. Diallel analysis based on disease incidence showed that more negative value was better than positive value. Genotype DMST531 showed more negative GCA value (-1.70) and the combination DMSK5xDMSS491 showed more negative SCA value (-2.11). The combination DMSK5xDMSS491 also showed more negative heterosis (-2.50%) and more negative heterobeltiosis (-2.50%) compared to the others. Additive variance was lower than dominant variance indicating downy mildew resistance is influenced by additive gene action. Third experiment studied combining ability and heterosis for yield and yield component in sweet corn. Resiprocal effect was not significant for all traits, indicating that gene location at nucleus more influential. Specific combining ability (SCA) x enviroment interaction was not significant for all traits, suggesting that screening at one location would be adequate. This experiment showed that non-additive gene action were more important for controlling inheritance of all traits. Genotype DMSG781 were good combiners for yield and yield per plot, genotype DMSE711 for ear diameter, ear rows, plant height and ear height. Genotype DMSF11 good combiners for ear lenght and rendement. Combination DMST531xDMSK5 were the best SCA for yield and yield per plot, DMSC499xDMSS491 for ear length, DMSS491xDMSF11 for ear diameter, DMSE711xDMSS491 for ear rows, DMSE711xDMSK5 for plant height and ear height. Combination DMSC499xDMSS491 have higher heterosis and heterobeltiosis for yield and yield per plot, DMSS491xDMSC499 and DMSK5xDMSE711 for ear lenght, plant height and ear height, DMSS491xDMSF11 for ear diameter, DMSK5xDMSS491 for rendement, DMSS491xDMSE711 for number of rows, DMSG781xDMSC499 for total soluble solid, DMSS491xDMST531 day of tasseling, day of silking and day of harvest.
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Judul: Formulasi Hamiltonian untuk Menggambarkan Gerak Gelombang Soliter Dimensi Tiga di Permukaan Laut
Abstrak: Gelombang permukaan adalah gelombang yang terjadi perbedaan rapat massa antara air dan udara. Salah satu gelombang permukaan yang ditinjau adalah gelombang soliter. Formulasi gelombang soliter dilakukan dengan menggunakan formulasi Hamiltonian.
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