Judul: Seleksi padi hibrida terhadap kekeringan untuk pengembangan di lahan sawah tadah hujan
Abstrak: The objective of the research was to determine method and character for early selection of rice to drought and to obtain drought tolerant hybrid rice genotypes to be used further in rainfed lowland. Experiments were conducted from April 2011 until July 2012 at Seed Science and Technology Laboratory, IPB and BB Biogen greenhouse Cimanggu, Bogor, at Babakan Experiment Station, IPB, Bogor, and at irrigated lowland, Cikembar, Sukabumi, and rainfed lowland, Gantar, Indramayu. The study consisted of seven experiments. The results showed that: (1) Polyethylene glycol (PEG) 6000 could detect and differentiate the response of hybrid rice genotypes to drought stress in both germination and seedling stage. The use of 25% PEG 6000 in the seedling stage could detect early hybrid rice genotypes tolerant to drought and have a compatibility with grouping of genotypes tolerant to drought based on yield criteria in the field. Variables of root dry weight, shoot dry weight and leaf dryness score were to detect hybrid rice genotypes tolerant to drought at seedling stage. (2) Genotypes BI485A/BP12, BI485A/BP15 and BI559A/BP15 under drought stress conditions decreased root length less (17.6 - 26.9 percent) than the IR64, the sensitive check variety (33.6 percent). Their grain weight, harvest index and grain yield (2.82, 2.58 and 2.72 ton ha-1) were higher than other genotypes. Moreover they were earlier to harvest, shorter in grain filling period and had sensitivity index to drought ≤ 0.50. Hybrid genotype tolerant to drought i.e BI599/BP15 under drought stress conditions had less stomatal density, maintained higher leaf relative water content, and contained non-structural carbohydrates in stem, sheath and leaf less than other genotypes. Genotypes BI485A/BP12, BI485A/BP15 and BI559A/BP15 were tolerant to drought and potentially could be developed for rainfed lowland; (3) The yield of these genotypes under irrigated lowland were not significantly different from those of Ciherang and Hipa 7 (i.e. 5.63, 6.87 and 6.30 ton grain ha-1, respectively). BI599A/BP15 genotypes under severe drought at rainfed lowland yielded 0.90 ton grain ha-1, whereas Hipa 7 and Limboto reached 0.34 and 0.29 ton grain ha-1, respectively.
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Judul: In vitro Selection For Drought Resistance On Rice
Abstrak: The rice demand is recently increasing , on the other hand the production is decreasing. It is caused by the long dry season due to the seasonal change. In addition, a lot of productive land has changed into industrial and settlement which in return minimize the number of productive land. To overcome this 2 varients with high yield and drought-stress resistant as in IR 64 variety should be produced. In this attemt, mutative induction combined with in vim culture and in vitro selection on the Gajahmungkur, Topwuti and IR 64 variants has been conducted and has yielded several somaclones which show the genetic variation. Through evaluation and characterization for the drought resistant using PEG 20% (BM 6000), several somaclone assumed to be drught resistant have been obtained. Subsequently, to find , out the mechanisme of the respective genotype toward the drought stress resistance, root penetration and proline content analysis at the somaclone have been $ conducted. From the evaluation, 23 Gajah mungkur somacloncs, 9 Towuti somaclones and 13 Ir 64 somaclones have been obtained as the ones with the high proline content. The drought stress treatment to the assumed drought stress resistent it is obtained 9 somaclones from Towuti, 5 from Gajahmungkur and 8 from IR 64 with the better characteristics under drought test than that of the main plants. Shorter plant with more shoots are obtained from Gajahmungkur but the seeds ripe earlier. From Tohti variants, more shoots and higher plants along with the more grain are obtained. From variety of IR 64 , somaclone which can produces seeds during the drought is obtained, meanwhile this does not happen with the plant originated from seed. The plants resulted from the selection produce more qualified shoot and grain than that of the main plants.
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Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology