Judul: Pemanfaatan Minyak Sereh dan Filtrat Trichoderma sp. untuk Mengendalikan Patogen Terbawa Benih Acacia mangium Willd.
Abstrak: This research is aimed at studying the potency of lemon grass oil and antagonistic fungus Trichoderma sp. in controlling pathogen carried by Acacia mangium Willd. The research was conducted in Forest Biotechnology Laboratory of Center for Natural Resources Reseach and Biotechnology IPB, and Cikabayan Experimental Station of IPB. The treatments were : (1) soaking seed in 0.1 % lemon grass oil, (2) soaking seeds in filtrate culture of Trichoderma sp., and (3) control (seeds without soaking). The experiment used complete randomized design with four replications. Variables observed were percentage of F. solani attack, peroxidase activity, and the length of seedling stem. The result reveals that treatments were not significantly different based on the variables observed. However, soaking seeds in filtrate culture of Trichoderma sp. tend to be better lengthen the stem seedling of A. mangium.
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Judul: Peran bakteri kitinolitik dan fungi mikoriza arbuskular dalam pengendalian busuk pangkal batang kelapa sawit
Abstrak: Basal stem rot (BSR) is the most serious disease of palm oil that caused by Ganoderma boninense Pat. The objectives of these researches were to find chitinase-producing bacterial which inhibit G.boninense growth and to determine the relationship between mycorrhizal and chitinolytic bacterial in controlling the BSR. The experimenthals were conducted in laboratory, secreen house dan fields. The research activities were: (i) exploration of chitinolytic bacterial as antagonistic agents of pathogens (ii) evaluate the pathogenicity, index chitinolitic of the chitinolytic bacterial and their antagonism effect against G. boninense, (iii) study on the application of chitinolytic bacterial and AMF in controlling the oil palm BSR through split plot experimenthal design. There were seven isolate B13, B14, B16, B42, Al11, TB41 and L34 have been selected as the best chitinolase-producing bacterial and they were not pathogenic to plants. The study showed that selected bacterial have differences on chitinolytic index. All of them suppressed the growth of G. boninense above 95% in vitro antagonism test using dual culture method on liquid media. However the antagonism test on PDA only isolate of AL11, TB41 and L34 had higher antagonism capacity against the pathogen. The severity of basal stem rot that expressed by the root necrotics were reducted since the oil palm seedling showed high degrees of mycorrhizal root colonization. The application of combination of chitinolytic bacterial and AMF suppressed the disease severity (95%) higher compare to the single one (55% - 7
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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