Judul: Pendugaan Parameter Genetik dan Respon Seleksi Genotipe Jagung (Zea mays L.) di Lingkungan Lahan Masam
Abstrak: Acid soil is a limiting factor for maize production in the world. Development of maize varieties tolerant to acid soil is needed in order to maintain sustainability of food production. The objectives of this research are to estimate the broad sense heritability and response to selection, and to identify potential genotypes for further utilization in a maize breeding program. This research was conducted at the Cikarawang experimental station, University Farm IPB, from November 2014 to March 2015. The experiment was arranged in an augmented design with 265 candidate genotypes from The Indonesian Cereals Research Institute (ICERI) Maros, South Sulawesi, along with seven check genotypes. The analysis of variance results showed that the effects of candidate genotypes are significant for all observed traits, except for ear height, stem diameter, and 100 seeds weight. Growth ability, days to anthesis, plant height, and yield components have high broad sense heritability, whereas number of ears per plant has low heritability. An index-based simultaneous selection exercise with 5% intensity resulted in 12 genotypes selected, namely 195, 252, 298, 166, 112, 256, 249, 369, 32, 231, 247, and 326. The estimated responses to selection are positive for all characters, except for days to anthesis and days to silking, as expected. The clustering result showed that all selected genotypes are grouped in the same cluster except genotype 369. These selected genotypes are considered potential as genetic sources for breeding acid soil tolerant maize varieties
Keyword: Bogor Agricultural University, acid soil, broad sense heritabiliy, maize, selection index, selection response

Judul: Evaluasi daya hasil tujuh jagung hibrida dan pendugaan parameter genetiknya
Abstrak: The objective of this research was to evaluate yield potential of seven hybrid maize genotypes from Balai Penelitian Serealia (BALITSEREAL) Maros (Maros Centre for Cereal Research) with five commercial varieties and to estimate the heritability value of the hybrid maize characteristics. The genotypes used in this experiment were B11-126/Mr15, CA00102-BBB/Mr15, E54-2-BBB/Mr15, N153/Mr15, N226/Mr15, (161/Nei9008-2)Mr15, (161/Nei9008-1)/Mr15, while comparing varieties were Bima-2, Bima-3, Bima-5, Bisi-16 and P21. The research was conducted on-farm at Pabuaran Village, Bogor on September 2009 to January 2010. This research used Randomized Complete- Block Design, single factor using four replications. The result showed that genotype N153/Mr15 produced higher total dry kernel weight and total dry grain weight than comparing varieties. Meanwhile, there were two genotypes with potential vegetative and yield characteristics, i.e. CA00102-BBB/Mr15 and E54-2-BBB/Mr15. Three of them were recommended to be evaluated in other locations (multi-location trial). Characteristics with high heritability values were days to anthesis, days to receptive, plant height, ear height, stem diameter, middle ear diameter, end ear diameter, base ear diameter, ear length, number of kernel rows, number of kernel/ear, total dry ear weight, total dry kernel weight and kernel/ear weight. Characteristics with medium heritability values were days to physiological maturity, total weight of wet ear, ear weight, and 1000 kernel weight, whereas low heritability value was found in total ear harvest characteristic.
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Judul: Bifurkasi lokal pada titik tetap non-hiperbolik
Abstrak: Bifurkasi menggambarkan perubahan pada struktur orbit di sekitar titik tetap. Titik tetap dibagi menjadi dua yaitu titik tetap hiperbolik dan titik tetap non-hiperbolik. Titik tetap non-hiperbolik terjadi jika ada nilai eigen dengan bagian real sama dengan nol. Kestabilan dari titik tetap dapat diketahui dari nilai eigen yang diperoleh dari pelinearan medan vektor. Pada bifurkasi satu-dimensi ditemukan kasus-kasus untuk bifurkasi saddle-node, bifurkasi transcritical dan bifurkasi pitchfork. Bifurkasi saddle-node terjadi jika satu sisi dari nilai parameter tidak terdapat titik tetap dan pada sisi lain terdapat dua titik tetap, dimana yang satu stabil dan yang lainnya tak-stabil. Bifurkasi transcritical terjadi jika terdapat pertukaran kestabilan, yaitu dari titik tetap stabil menjadi titik tetap tak-stabil dan sebaliknya. Sedangkan bifurkasi pitchfork dibagi menjadi dua, yaitu: bifurkasi pitchfork supercritical dan bifurkasi pitchfork subcritical. Bifurkasi pitchfork supercritical terjadi jika satu titik tetap stabil berubah menjadi dua titik tetap stabil dan satu titik tetap tak-stabil, dan bifurkasi pitchfork subcritical terjadi jika satu titik tetap stabil dan dua titik tetap tak-stabil berubah menjadi satu titik tetap tak-stabil. Bifurkasi Hopf (bifurkasi dua-dimensi) terjadi jika terdapat orbit periodik pada struktur orbitnya yang berupa lingkaran dengan jari-jari konstan. Ada atau tidaknya orbit periodik dapat diketahui setelah sistem ditransformasikan ke dalam koordinat polar. Orbit periodik ini dapat bersifat stabil maupun tak-stabil. Model periklanan (advertising) Feichtinger merupakan salah satu contoh penerapan bifurkasi Hopf Model ini menghasilkan satu titik tetap dan orbit periodik yang bersifat stabil.
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