Judul: Induksi Pembungaan dan Perbaikan Mutu Buah Srikaya Jumbo (Annona squamosa L.)
Abstrak: Sugar apple (Annona squamosa-Annonaceae) is one of favorite local fruits. The main constraint in increasing fruit production is low flower production and dichogamy in which male and female reproductive organ did not mature at the same time. The objectives of this research were to increase flower production by pruning and to improve fruit quality by pollination. The research was conducted in Pakem, Sleman, North Yogyakarta in February until July 2013. The research consisted of two experiments, both were arranged in randomized complete block design with one factor. The factor for the first experiment was pruning i.e. total pruning, partial pruning, and unprunned as control. The second experiment was started with observation on flowering phenology from appearance of flower buds to anthesis, and continued on the receptive period of stigma. Following the observation pollination in which three types of pollination was employed, i.e. controlled pollination, natural pollination, and modified natural pollination. The result of the first experiment showed that flowering increased by total pruning up 83.3% and by partial pruning up to 41.8% compared to unprunned trees. The fruit yield from totally prunned trees was 5%, partially prunned was 3.9%, and unprunned was 2.2% of the flower bud appearance. Observation on flowering phenology showed that development of flower bud appearence until anthesis took 25-34 days. The receptivity of the stigma occurred twice during 05.00 am - 14.00 pm and 17.00 pm - 02.00 am. Controlled pollination resulted in 90 % fruit set as compared to 70 % fruit set in natural and modified natural pollination. Controlled pollination produced more symetrical fruit, ranged 136.8-287.8 g, natural pollination ranged 150.0-367.8 g. Modified natural pollination produced the smallest fruit ranged 82.0-235.2 g.
Keyword: sugar apple, stigma receptivity, pollination, pruning, dichogamy

Judul: Flowering biology and parthenocarpy of citrus derived from somatic hybridization of Mandarin Satsuma (Citrus unshiu Marc.) and Siam Madu (Citrus nobilis Lour.)
Abstrak: Fusi protoplas antara Mandarin Satsuma (Citrus unshiu Marc.) dan Siam Madu (Citrus nobilis Lour.) diharapkan menghasilkan buah dengan rasa yang enak dan mempunyai biji sedikit, namun kenyataannya menghasilkan hibrida dengan variasi genetik yang tinggi. Tujuan penelitian ini adalah mendapatkan informasi biologi pembungaan dan pembentukan buah serta sifat partenokarpi jeruk hasil fusi protoplas antara Mandarin Satsuma dan Siam Madu. Penelitian dilaksanakan di KP Pacet BB Biogen, Cianjur (1150 m dpl), selama Agustus 2019 – Juli 2020. Bahan penelitian berupa 15 galur jeruk hasil fusi protoplas (Mandarin Satsuma dan Siam Madu), masing-masing terdiri atas 5 tanaman (umur ± 2 tahun), yang diperbanyak secara okulasi dengan batang bawah JC (okulasi pada bulan Juni 2017). Biologi pembungaan diamati secara deskriptif mencakup morfologi bunga, perkembangan bunga dan buah, viabilitas serbuk sari dan reseptivitas stigma. Pembentukan buah dan biji dari bunga tanpa penyerbukan, penyerbukan sendiri dan silang untuk mendapatkan informasi adanya sifat partenokarpi pada tanaman hasil fusi protoplas. Hasil pengamatan menunjukkan bahwa morfologi bunga galur-galur tanaman jeruk hasil fusi protoplas cukup beragam dan mewarisi karakter kedua tetuanya. Fase pembentukan bunga hingga buah masak bervariasi antar galur, dengan lama perkembangan yang berkisar 212 – 316 hari. Media yang tepat untuk pengecambahan serbuk sari menggunakan media PGMm. Viabilitas serbuk sari tertinggi dan masa reseptif stigma tercapai pada saat bunga mekar sempurna. Galur FS 25 menghasilkan serbuk sari dengan viabilitas yang paling rendah dan buah tidak terbentuk tanpa penyerbukan. Penyerbukan sendiri FS 25 dan penyerbukan silang dengan FS 84 dan FS 89 menghasilkan persentase buah tanpa biji tertinggi. Penyerbukan antar galur yang cross-compatible diperlukan untuk produksi buah tanpa biji pada galur dengan potensi partenokarpi stimulatif yang kuat. FS 25 memiliki karakter partenokarpi stimulatif, dan FS 84 dan FS 89 dapat digunakan sebagai sumber serbuk sari untuk menstimulasi pembentukan buah tanpa biji., The somatic hybridization between Mandarin Satsuma (Citrus unshiu Marc.) and Siam Madu (Citrus nobilis Lour.) is expected to produce seedless fruit with good taste, but in fact produces hybrids with high genetic diversity. The purpose of this study was to obtain information on flowering biology and fruit formation as well as the parthenocarpic characters of the genotypes from somatic hybridization between Mandarin Satsuma and Siam Madu. The research was carried out at Pacet Experimental Station, BB Biogen, Cianjur (1150 m asl), during August 2019-July 2020. The research materials were 15 citrus lines resulting from somatic hybridization (Mandarin Satsuma and Siam Madu), each consisting of 5 plants (± 2 years old), which were propagated by grafting with JC rootstocks (grafting at June 2017). Flowering biology was observed descriptively including flower morphology, flower and fruit development, pollen viability and stigma receptivity. Development of fruit and seeds from flowers without pollination, self-pollination and cross-pollination were observed to invertigate the existence of parthenocarpy in plants resulting from somatic hybridization. The result showed that the flower morphology of citrus somatic hybridization lines varied and inherits the characters of both parents. The development from flower bud until fruit ripening varied among lines, ranged 212-316 days. The modified PGM was the most suitable for citrus pollen germination. The pollen viability was the highest at blooming during which
Keyword: BBCH, numbers of petal, stimulative parthenocarpy, self-pollinated, pollen viability

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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