Judul: Morphological and genetic diversity and degree of competition of several Echinochloa crus-galli (L.) Beauv. accessions to rice.
Abstrak: Weed disturbance is an important issue in rice production in Indonesia. Echinochloa crus-galli (L.) Beauv. is the most dominant weed in rice leading to loss of production. The research aims to analyze the morphology and genetic diversity of weeds accession E. crus-galli from West Java and degree of competition of E. crus-galli to rice. Research was carried out by using several steps, i.e : (1) Preliminary experiments on growth and production of rice with E. crus-galli weed population levels originating from three locations, (2) Morphological and genetic evaluation, (3) Identification of potential weed allelophaty E. crus-galli accession, (4) Study effect of E. crus-galli accession on the growth and rice production (greenhouse experiments), (5) Effects of accession and population rate of E. crus-galli on the growth and rice production (field trial), (6) Estimation of degree competition of E. crus-galli by the replacement series method, (7) Study of physiology competition between rice with weeds. Results showed that E. crus-galli accession from West Java exhibited morphological and genetic diversity. Accession from different geographical locations showed differences in morphology. The diversity of morphology is presumably due to the phenotypic plasticity and adaptation ability of E. crus-galli accessions. Cluster analysis based on SSR molecular markers produced four sub-groups with similarity coefficient of 0.86, with most of the group clustered in geographic zones of western West Java and northen. This genetic diversity might be caused by the movement of genetic material through harvest or through irrigation, isolation distance, and the possibility of mutation. E. crus-galli accessions had the potential allelophaty based on inhibit of radicle and plumula growth of rice. Based on the potential allelophaty, the accessions clustered to six groups at 0.72 similarity coefficient. Each accession of E. crus-galli showed a potential difference in reducing the growth and yield of rice plants. This ability is probablt related to morphological characteristics and allelophatyic potential. Accession K6 from Karawang showed the highest ability to suppress the growth and production of rice plants. E. crus-galli weed had a higher degree of competition to rice plants when the weed population was higher than the population of rice plants. Based on the value of aggressiveness, E. crus-galli competed stronger than rice when the population of rice plants and weeds is equal or weed population was higher than that of rice population. Each rice variety had a different response to population levels of E. crus-galli. The competition between rice plants with a E. crus-galli inhibited the physiological process of rice plant.
Keyword: Oryza, Field crops

Judul: Evaluasi Toleransi Genotipe Padi Sawah (Oryza Sativa L.) Pada Persaingan Dengan Gulma Echinochloa Crus-Galli.
Abstrak: Salah satu masalah utama dalam budidaya tanaman padi adalah adanya gangguan gulma. Gulma dapat menyebabkan kehilangan hasil lebih besar dibanding organisme pengganggu lainnya. Echinochloa crus-galli merupakan salah satu gulma penting pada pertanaman padi sawah. Gangguan yang ditimbulkan gulma ini berupa persaingan dalam memperebutkan sumber daya terbatas yang tersedia di lahan. Tujuan penelitian ini adalah untuk memperoleh karakter agronomi yang dapat digunakan sebagai indikator toleransi genotipe padi sawah dalam berkompetisi dengan gulma E. crus-galli dan genotipe padi yang mampu berkompetisi dengan gulma E. crus-galli. Penelitian terdiri atas percobaan rumah kaca, menggunakan pot di rumah kaca Balai Besar Biogen, Bogor, dilanjutkan dengan percobaan lapangan yang dilaksanakan di lahan sawah Desa Cibanteng, Kec. Ciampea, Bogor. Hasil percobaan I menunjukkan bahwa perlakuan kompetisi dengan 4 gulma E. crus-galli pot-1 mengakibatkan penurunan relatif pada karakter tinggi tanaman, jumlah anakan produktif, jumlah gabah isi per malai, bobot kering tajuk per rumpun dan bobot gabah per rumpun. Kriteria toleransi genotipe ditentukan berdasarkan rata-rata nilai tengah dan standar deviasi persentase penurunan relatif bobot gabah per rumpun, jumlah anakan produktif dan bobot kering tajuk per rumpun. Berdasarkan analisis data diperoleh 3 genotipe toleran (IR10L-155, IR10L-133 dan BIO-R84-1 ), 19 genotipe moderat (KP1-3-1-2, KP4-42-2-1, KP4- 42-2-3, KP4-43-1-2, IR83821-16-2-3-2, IR83821-99-2-2-2, IR81493-B-B-B-6-B- 2-1-2, IR82806-98-3-2-2-2-1, IR83840-90-3-2-1, IR85640-114-2-1-3, IR85627- 46-1-2-3, IR10L-130, IR10L-152, IR10L-135, IR10L-139, BIO-R68, BIO-R100, IR 64, Fatmawati) dan 3 genotipe peka (IR84778-53-1-2-2-1, IR80376-12-2-3-3, IR78119-24-1-2-2-2). Berdasarkan nilai korelasi komponen hasil terhadap bobot gabah per rumpun, jumlah anakan produktif (r=0.89) dan bobot kering tajuk (r=0.87) dapat dijadikan indikator toleransi genotipe padi dalam persaingan dengan 4 gulma E. crus-galli pot-1 . Perlakuan kompetisi dengan 6 rumpun gulma E. crus-galli m-2 di lapangan mengakibatkan penurunan pada karakter tinggi tanaman, jumlah anakan produktif, jumlah gabah isi per malai, dan produktivitas padi. Genotipe IR10L-155 dan IR10L-133 merupakan genotipe yang secara berurutan memiliki produktivitas paling tinggi 5.96 ton ha-1 dan 4.91 ton ha-1. Hal tersebut mengonfirmasi hasil percobaan I yang menunjukkan kedua genotipe memiliki bobot gabah per rumpun lebih berat dibandingkan genotipe lainnya pada kondisi bersaing dengan 4 rumpun gulma E. crus-galli pot-1. Hasil analisis korelasi menunjukkan jumlah anakan produktif dan jumlah gabah isi per malai layak dijadikan indikator toleransi genotipe padi dalam bersaing dengan 6 rumpun gulma E. crus-galli m-2 .
Keyword: Jajagoan, kompetisi, penurunan hasil

Judul: Pembuatan Film Tipis Cu2ZnSnS4 sebagai Lapisan Penyerap Cahaya pada Sel Surya Menggunakan Metode Elektrodeposisi
Abstrak: Thin film of Cu2ZnSnS4 (CZTS) is an alternative semiconductor used as light absorber layer on solar cell. CZTS can replace silicon that commonly used as commercial semiconductor. The advantage of using CZTS as absorber layer is due to the abundance of its chemical composer on earth, and its high value of absorption coefficient. The absorber layer was made by using electrodeposition method on ITO glass substrates. The films were deposited at room temperature using potentiostatic mode with a potential of –1.05 V for 30, 45, and 60 minutes. After that, the films were annealed at two different temperatures, 180 ºC and 500 °C, for 45 minutes in N2/H2S atmosphere. Based on X-ray diffraction analysis, the polycrystalline thin film obtained fall into kesterite crystal phase. This type of crystal was obtained when the CZTS was annealed at 500 °C in H2S/N2 atmosphere. The value of optical band gap energy for the CZTS thin film was 2.2 eV with the film thickness about 1.228–6.366 μm. The sample of CZTS with electrodeposition time of 45 minutes and annealing temperature of 500 °C showed the best result and in conformity with absorber layers criteria for solar cells.
Keyword: semiconductor, ITO glass, CZTS thin film, electrodeposition