Judul: Morphology and physiology adaptation of some soybean genotypes [Glycine max (L.) Merr] to drought and aluminium stress
Abstrak: The experiment was carried out to study the effect of drought and aluminium (Al) stress on morphological, physiological and yield component of tolerant and sensitive soybean genotypes. This experiment was conduct on two phase. At first was on June to September 2010 and use a randomized block design (RBD), which consists of three factors: 1) soybean genotypes (Anjasmoro, SC 56-3, PG 57-1, SP 30-4 and Tanggamus), 2) soil water content (100% , 75% and 50% field capacity), 3) the level of Al neutralization (100% neutralization, 75% neutralization and 50% neutralization). Genetically there were differences on plant height, number of leaves, leaves dry weight and root dry weight. Drought decreased plant height, number of leaves, leaves, root and nodules dry weight in most all genotypes. Stems dry weight and number of branches were affected by interact between genotype and water level. Drought and Al stress decreased stems dry weight mostly on all genotypes. On physiological parameter, leaves color index (LCI) and chlorophyll b content, were affected by genotypes. Otherwise, drought increased LCI, chlorophyll a and b content. Al stress decreased chlorophyll b content. The yield component of all genotypes were variety depend on each water level and Al neutralization. Water use efficiency (WUE) on water level 100% field capacity and neutralization Al 100% were optimal condition on most genotype. There were 10 parameters have positive correlated with yield, there are: plant height, number of leaves, number of branch, leaves dry weight, stems dry weight, roots dry weight, pods dry weight, number of pods, number of full pods and pods weight. The result of sensitivity index analysis on 10 variables were classified PG 57-1 as tolerant and SP 30-4 as sensitive genotype to drought and Al stress. The second phase axperiment was conduct on November 2010 to February 2011, use a randomized block design (RBD), which consists of three factors: 1) two soybean genotypes (PG 57-1 and SP 30-4), 2) two level of soil water content (75% and 50% field capacity), 3) the level of Al neutralization (100% neutralization, 75% neutralization and 50% neutralization). There were no differences between tolerant and sensitive genotype on proline content, net assimilation rate (NAR) and relative growth rate (RGR). But on tolerant genotype, nodules dry weight were higher than the sensitive one.
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Judul: Respon pertumbuhan tanaman kedelai [Glycine max (L.) Merr.] pada kondisi kekeringan dan cekaman aluminium
Abstrak: The government has launched the soybean self sufficiency by 2014 in an effort to enough needs domestic of soybean . This will be achieved by increased productivity , expansion of cropping intensity and extension of planting area. A extension of the planting area is to utilize marginal lands. The mostly marginal lands in Indonesia is dryland acid soil and has the potential to be developed as an extension of planting area. The cultivation in dryland acid soil had several constraints, such as drought and high solubility of Al3+. The soybean response to water deficit varies depending on the genotypes, and the duration of the stress and growth phase. High solubility of Al3+ in the soil inhibits root growth. The experiment was carried out to study the growth response and the mechanisms of adaptation the soybean genotypes to drought and aluminum stress, which consists of the two stages experiments. The first stage was carried out to study the effect of genotype, drought and aluminium stress on the vegetative and generative growth and the plant roots of soybean. The second stage was carried out to study the effect of genotype, drought and aluminium stress on component crops of soybean. This experiments was conducted in Januari to November 2011, in the greenhouse Cikabayan, University Farm, IPB Darmaga Bogor. This study used a randomized complete block design, with three factors: 1) soybean genotypes (SP 30-4, Anjasmoro, PG 57-1 and Tanggamus), 2) watering interval (2 days, 6 days and 10 days, 3) the level of Al neutralization (0% neutralization and 100% neutralization). The results show that the adaptation mechanism avoidance of soybean geno types was only seen in PG57-1 on root length variables when gripped by drought. This mechanism can be seen from its root elongation when gripped by drought. The higher of value of the observed variables would be the higher the number of pods produced. It also happens to variable root dry weight and dry weight of root nodules. In general, yield components of soybean more influenced by drought stress. However, flowering only variable affected by Al stress on different genotypes.
Keyword: aluminium stress, drought stress, the mechanisms of adaptation

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