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: Resistance Test toward of 48 Lines Rice to Blast Disease (Pyricularia oryzae) Race 001
Abstrak: Blast disease, caused by Pyricularia oryzae Cav., is one of the major fungal diseases infected rice (Oryza sativa L.) in Indonesia. The aim of this research was to examine the resistance of rice from the infection of P. Oryzae race 001 and to detect the existance of Pi-ta gene in resistant lines of rice. Resistance evaluation to blast disease (Pyricularia oryzae) on Cisadane (resistant), Kencana Bali (susceptible) as control, and 48 lines of rice was carried out in the green house by using injection inoculated method with P. oryzae race 001. Rice seedling were planted on sterilize soil, and sixteen days old of rice were soaked in the fungal spore suspension (105 spores/ ml) in the dark for 24 hours, and moved to the light. Rice disease was observered on 7-9th days after infection. There were 2 step screening of blast-resistant, which screening I performed a total of three replicates and screening II performed from selected plant in screening I a total of two replicates for each line of rice, with 10 plants in each replication. The result of second screening at green house showed that 13 lines resistant to P. oryzae 001 were IPB140-F-2-1, IPB115-F-4-2-2, IPB113-F-2-2, IPB107-F-7-3, IPB140-F-5, IPB149-F-2, IPB149-F-8, Martapura, IPB149-F-4, IPB149-F-5, IPB113-F-1, IPB102-F-92-1-1, IPB107-F-5-1 with the percentage of resistance ≥ 80 %. Two pairs of DNA primers specific to the dominant indica Pi-ta gene were designed from DNA sequence in gene bank with accession number AF207842 to amplify the Pi-ta DNA fragments by polymerase chain reaction (PCR) method. The results revealed that all of 13 resistant and 2 susceptible lines (IPB107-F-18-4-2 and IPB107-F-16E-6) of rice carrying Pi-ta genes, even in Kencana Bali. The previous experiment shown that Kencana Bali does not have Pi-ta resistance gene. It is expected that Kencana Bali has deletion of Pi-ta resistance gene in the end part of exon 2. Further more, those results also indicated that Pi-ta gene did not confer resistance to race 001 of Pyricularia oryzae. Resistance to P. oryzae race 001 might be controlled by different resistant gene.
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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