Lihat Juga

• Productivity of Amorphophallus muelleri is considered low. Thus, pot experiment was conducted at the Cikabayan Experimental Farm, Bogor Indonesia during rainy season November 2007 to July 2008, in order to determine the optimum fertilizer dose for A. muelleri under 50% shading net. Treatments consisted of four doses of nitrogen (0, 50, 100 and 150 kg ha-1 N) and three doses of potassium (0, 50 and 100 kg ha-1 K2O). The results showed that application of N and K fertilizers significantly increased vegetative growth, i.e., number of leaves, number of leaflets and second leaf size, but did not affect harvesting time. Fresh weight and dry matter content of daughter corm were significantly affected by N and K applications. Combination of 50 kg ha-1 N and 100 kg ha-1 K2O resulted in higher corm weight than other treatments. It is evident that the application of nitrogen and potassium is important in A. muelleri. Keywords: disease infection, iles-iles, Indonesian konjac, nitrogen, potassium
  oleh: Santosa, Edi; Department of Agronomy and Horticulture, Faculty of Agriculture, Bogor Agricultural University, Jl. Meranti, Kampus IPB Darmaga 16680, Indonesia
• This research was aimed to study the effect of stem and primary branch prunning on photosynthetic rate and production of physic nut. The experiment was conducted in IPB experimental station in Cikabayan, Darmaga, Bogor, from February 2007 until May 2008. A randomized block design with one factor was used in the experiment. The treatments were combination between stem pruning with various height from the soil surface and pruning of primary branches with various number of branch remained. Stem pruning on 40 cm above the soil surface with no branch pruning resulted in the highest photosynthetic rate (8.10 μmol CO2 m-2 s-1), while stem pruning on 20 cm above the soil surface with 2 primary branches remained resulted in the lowest photosynthetic rate (4.71 μmol CO2 m-2 s-1). Stem pruning on 40 cm above the soil surface without branch pruning produced the highest yield components, i.e., capsul number (207.3 capsul plant-1), seed number (506 seeds plant-1) and seed dry weight (323.81 g plant-1). Keywords: photosynthetic rate, production, stem prunning
  oleh: Hariyadi, ,; Department of Agronomy and Horticulture, Faculty of Agriculture, Bogor Agricultural University, Jl. Meranti, Kampus IPB Darmaga 16680, Indonesia
• Yard long bean (Vigna unguilata L.) 777 was grown in Ultisols, which typically have low pH and high P-fixation, to determine the best correlation of soil extraction methods for soil P with yields, and to develop soil P response categories. The research was conducted at SANREM base camp in Hambaro Village, Nanggung, Bogor, Indonesia from April-August 2008. Treatments were arranged in a Split Plot Design with three replications. The main plots were treatments with soil P status of 0X, 1⁄4X, 1⁄2X, 3⁄4X and X, where is X = 1,590.5 kg SP-36 ha-1 (36% P2O5) applied once a month before planting. The subplots were P application rate of 0, 75, 150, 225 and 300 kg P2O5 ha-1. Yard long beans were planted in double rows per bed, 60 cm between rows and 25 cm within rows, 2 seeds per hole, with plot size of 1.5 m x 5 m. Coefficient correlation (r) of extraction reagents Olsen, Bray-1, HCl 25%, and Mechlich-1 were 0.772, 0.765, 0.755, and 0.732, respectively. Based on Olsen soil testing methods, soil response categories of very low, low, medium, and high were (ppm P2O5) ≤ 18.40, 18.40 < P < 117.27, 117.27 < P < 267.04, and ≥ 267.04 extracted-P, respectively. Based on Bray-1 soil testing methods, soil response categories for low, medium, and high were ≤ 87.81, 87.812O5), respectively. Fertilizer recommendation based on the Olsen soil test for low response category was 185.75 kg P2O5 ha-1, and for the medium soil category was 175.97 kg P2O5 ha-1. The Bray-1 soil test for the low response category was 184.31 kg P2O5 ha-1, and for the medium soil category was 161.39 kg P2O5 ha-1. Keywords: fertilizer recommendation, calibration, phosphorus, yard long bean
  oleh: Susila, Anas Dinurrohman; Department of Agronomy and Horticulture, Faculty of Agriculture, Bogor Agricultural University, Jl. Meranti Kampus IPB Darmaga 16680, Indonesia
• To accomplish the study of genetic parameters of chili resistance to P. capsici, thirty cross combinations from six parents’ crosses were made by full diallel method. The resistance was assessed based on the incidence of disease, following the inoculation of 28 days-old plant of chili. Inoculation was done by dropping 5 mL of inoculum (105zoospore mL-1) at the base part of each plant. There was non-allelic interaction and overdominance effect. Chili resistance to P. capsici controlled by one positive gene. The parents contained more dominant gene, with dominance order were IPB-C4, IPB-C10, IPB-C15, IPB-C9, IPB-C8, and IPB-C2. The prediction of the possible limits of selection if homozygote genes assemble on one individual was 0.676-0.691. Broad-sense and narrow-sense heritability values for the traits were high. Keywords: chili, diallel analysis, genetic parameter, Phytophthora capsici
  oleh: Yunianti, Rahmi; 1 Department of Agronomy and Horticulture, Faculty of Agriculture, Bogor Agricultural University, Jl. Meranti, Kampus IPB Darmaga 16680, Indonesia
• The effect of P fertilizer rates on growth and production parameters of waterleaf [Talinum triangulare (Jacq.) Willd] were studied over two months (February-April 2010) in Bogor. Treatments of five P-rates (0, 200, 400, 600, and 800 kg SP-18 ha-1) were laid out in a randomized complete block design with three replications. Generally, the effect of P fertilization in waterleaf was mostly prominent at 8th week after planting (WAP). The increase of P rates increased leaf area, leaf fresh weight, edible part (shoot weight), and protein production; but decreased anthocyanin production. These results suggested that to produce high protein and anthocyanin, waterleaf must be fertilized with 400 kg SP-18 ha-1; and P fertilizer must be applied at least two weeks before planting. Keywords: inorganic fertilizer, phosphorus, portulacaceae, secondary metabolite
  oleh: Mualim, Leo; Department of Agronomy and Horticulture, Faculty of Agriculture, Bogor Agricultural University, Jl. Meranti, Kampus IPB Darmaga 16680, Indonesia