Judul: Genetic analysis and selection of lowland rice (Oriza sativa L) genotypes for adaptation in highland ecosystem
Abstrak: One of the important factors to ensure the success of rice breeding programs for increasing yield and tolerance to environmental stress condition is selection producers.
Keyword: low temperature stress tolerance, promising lines, selection index, West Java, South east Sulawesi

Judul: Keragaan karakter agronomi dan stabilitas genotipe padi pada ekosistem dataran tinggi
Abstrak: Rice is the most important staple food in the world. Development of rice cultivation area is needed to increase rice productivity through expanding of marginal land especially in high-elevation areas of Indonesia. Temperature, solar radiation and rainfall influence rice yield by directly affecting the physiological processes involved in grain production. The effects of abiotic stress on grain yield and yield components vary with growth stage, depending on variety and weather condition. The major constraint of rice cultivation in high elevation area is lack of cold tolerance varieties. The objectives of this research were to obtain the information of agronomic traits performance and stability of rice genotypes to be adapted in highland across three different high-elevations (700, 900 and 1200 m above sea level). The rice genotypes derived from mutation induction and hybridization treatment were cultivated in dry season (2011) and rainy season (2011/2012). Forty rice genotypes were used in dry season cultivation across two different high-elevations (700 and 1200 m above sea level). Twenty five rice genotypes were selected based on agronomic trait performance and grain yield in dry season and then cultivated in rainy season across three different high-elevations (700, 900 and 1200 m above sea level). Four stability analysis methods i.e. Finlay- Wilkinson, Eberhart – Russel, Francis - Kannenberg and AMMI were applied to analyze the stability of promising lowland rice lines. The results showed that the difference of high elevations had influenced on yield in dry season due to low air temperature (15ºC) during flowering period while there was no significantly effect in rainy seasons across three different high elevation areas. A minimum daily air temperature below 17°C in flowering period caused high unfilled grain numbers, low filled grain percentage, reduced grain weight, low panicle numbers, incomplete panicle extension, extended maturity date, extended grain filling period and low yield which varied among genotypes. Stability analysis indicated that some promising rice lines well adapted in different high altitudes areas. There were 12 rice lines stable based on Finlay Wilkinson method, Eberhart and Russell method (6 rice lines), Francis and Kannenberg method (16 rice lines) and AMMI models revealed three stable rice lines. The OS-30-199 mutant line produced the highest yield (4,69 ton/ha) among genotypes observed which highly significant over check variety, Sarinah (3,42 ton/ha).
Keyword: 

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