Judul: Blast resistance introgression of oryzica llanos-5 on the advanced backcross population way rarem x oryzica Llanos-5
Abstrak: Upland rice is an alternative resource for enhancing rice productivity in Indonesia. However upland rice cultivation technology is still not optimum, particularly in controlling blast pathogen (Pyricularia oryzae). The development of cultivar multiline using NIL (Near isogenic lines) population is one of the important efforts to prevent the breaking down of blast resistance in field. The advanced backcross lines were developed using the recurrent parent Way Rarem, which is high yielding but recently was destroyed by blast, and the durable blast resistant Oryzica Llanos-5, as a donor parent. The study was aimed 1) to develop NIL Way Rarem x Oryzica Llanos-5 having a higher blast resistance compared to Way Rarem; 2) to obtain molecular markers which could detect the introgression segment of blast resistance-carrying donor on the advanced backcross lines; and 3) to get information about the blast resistance inheritance of Oryzica Llanos-5. The evaluation of blast resistance demonstrated that the percentage of the blast resistant plant on BC4F1 and BC5F1 were higher than that on BC3F1 and BC4F1, respectively. The blast test using each 133 and 173 blast races on BC5F1 showed that there were several BC5F1 plants having a higher blast resistance to each both blast races compared to Way Rarem. This high blast resistance character might be derived from the introgression segments of Oryzica Llanos-5. The detection of blast resistance introgression from Oryzica Llanos-5 using SSR primers on BC3F1 population demonstrated that three markers (RM411, RM7 and RM251) on chromosome 3 and three markers (RM276, RM549 and RM585) on chromosome 6 were polymorphic markers and could identify the donor introgression based on the appearance of heterozygous allele on PCR amplification. The six SSR markers and the evaluation of blast resistance were used to select the plant on each BC4F1, BC5F1 and BC6F1 generation which was backcrossed to Way Rarem. Based on the genome wide scan in the blast resistant BC6F1 plant we found several SSR markers which could detect the donor introgression on chromosome 2, 3, 6 and 8. RM207 and RM266 were on chromosome 2, also RM404 was on chromosome 8. This is interesting information because the introgression segment on both chromosomes could not detect in earlier research by Lestari et al. (2011). Both introgression segments were located quite close to blast resistance QTL derived from Oryzica Llanos-5 alleles in RIL population Fanny x Oryzica Llanos-5 that the introgression segment on chromosome 2 was located close to Pib gene and on chromosome 8 was located close to Pi33 gene. In addition there were also introgressions segment of Oryzica Llanos-5 on chromosome 3 that could be detected by RM565 and RM514 which were similar position with blast resistance QTLs on population of cross between Fanny x Oryzica Llanos-5 varieties.
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Judul: Molecular Marker Application on Selection of A Rice Backcross Population derived from a Cross between IR64/Hawara Bunar to Obtain Aluminum-Tolerant Rice Lines
Abstrak: Since 1971 the increase of food demand in Indonesia, especially rice is much greater (181.6%) than the increase of population (108%), therefore an effort to increase rice production is unavoidable. Currently, the ability of agricultural land to provide area for rice cultivation tends to decline from year to year due to massive conversion of productive lands into industrial and residential uses. The situation leads to expand rice cultivation into the utilization of marginal lands, such as acid soils for rice cultivation. However, rice cultivation in acid soils will face many constraints, which mainly due to the aluminum (Al) toxicity. The use of Al-tolerant rice varieties with high productivity will be an alternative solution to overcome the Al toxicity problem in acid soils. There is an Indonesian local rice genotype named Hawara Bunar that tolerant to Al stress and can be used as a Al-tolerant donor parent in rice breeding program. However, the potential productivity of the genotype is not as high as rice cv IR64. The use of a backcross population derived from a cross between both genotypes with cv IR64 as a recurrent parent is an approach to develop Altolerant rice cultivar with high productivity. It has been identified that a Quantitative Trait Loci (QTL) for Al-tolerance trait is located on the short arm of rice chromosome 3 flanked by markers RM489 and RM517 (Miftahudin et al. 2008; Akhmad 2009). The objectives of the study were to (1) increase molecular markers density in the area of QTL for Al-tolerance trait on rice chromosome 3 flanked by two SSR markers RM489 and RM517, (2) re-identify QTLs for Al tolerance trait in the previous Al-tolerance QTL area on rice chromosome 3, (3) and carry out marker assisted backcross selection (MABS) ob a rice backcross population derived from a cross between IR64/Hawara Bunar to obtain Al-tolerant rice lines with superior agronomic traits. The research was conducted from September 2009 to May 2012 at the Laboratory of Plant Physiology and Molecular Biology, Department of Biology, Bogor Agricultural University and at the Research Institute for Agricultural Biotechnology and Genetic Resources (Biogen) Bogor. An F2 population derived from a cross between rice cv IR64 and Hawara Bunar were used to increase marker density and re-identify Al-tolerance QTL, while BC2F1 plants and BC2F2 populations that have been developed from the previous and this studies, respectively, were selected through MABS combined with physiological and agronomic characters based selection. An amount of 17 SSR markers were screened for polymorphism between the two parents to obtain markers that being used to increase marker density. Five markers, which were RM2790, RM545, RM14535, RM14543, and RM14552, were polymorphic and could be mapped in between markers RM489 and RM517 with the average distance of 3 cM between adjacent markers. Al-tolerance QTL were identified in the previous QTL location between markers RM2790 and RM14552 (LOD 3.4) based on the Main Root Elongation characters. Foreground and background selections were successfully carried out on BC2F1, BC2F2 and BC2F3 populations using five foreground and 50 background SSR markers. The MABS obtained two BC2F3 rice lines (number 175-63-34 and
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf