Analysis of Genotype by Environment Interaction on Cocoa Hybrids (Theobroma Cacao L.) Resistance to Phytophthora Pod Rot

Phenomenon of genotype by environment interaction was able to influence the stability performance of cocoa resistance to Phytophthora pod rot (PPR). This research had an objective to evaluate the effect of genotype by environment interaction on resistance of cocoa hybrids to PPR. The tested hybrids were F1 crosses between selected clones of TSH 858, Sulawesi 1, Sulawesi 2, NIC 7, ICS 13, KEE 2 and KW 165. There were 14 tested hybrids and an open pollinated hybrid of ICS 60 x Sca 12 was used as control in multilocation trials at four different agroclimatic locations, namely Jatirono Estate ((highland-wet climate), Kalitelepak Estate (lowland-wet climate), Kaliwining Experimental Station (low land-dry climate) and Sumber Asin Experimental Station (highland-dry climate). Trials were established in the randomized complete block design with four replications. Resistance to PPR were evaluated based on the percentage of infected pod for the years during wet climate of 2010 in Jatirono, Kalitelepak and Kaliwining followed in dry climate of 2011–2015 in Kaliwining and Sumber Asin. Variance of data were analyzed for detecting the effect of genotype by environment interaction (GxE) then visualized with a graph of genotype main effect and genotype by environment interaction (a graph of GGE) biplot. There was consistently no interaction effect between hybrid and location to PPR incidence which was affected by single factor of hybrid, year, location and interaction between year and location. The effect of year indicated yearly change of weather was more important to PPR incidence than location difference. A graph of GGE biplot indicated a stable performance of the tested hybrids among locations

Pemodelan Nilai Tukar Rupiah terhadap $Us Menggunakan Hidden Markov*

Perilaku nilai tukar Rupiah terhadap $US dari tahun 1998 sampai dengan 2005 dicoba dimodelkan dengan menggunakan Hidden Markov (Elliott, et. al. 1995) Pendugaan parameter model dilakukan mengunakan Metode Maximum Likelihood dan pendugaan ulang menggunakan metode Expectation Maximization yang melibatkan Perubahan ukuran. Hasil yang diperoleh kurang baik karena galat antara nilai harapan dengan nilai sebenarnya cukup besar

Chromatographic Identification of Leaf Color Characteristics on Fine-flavor and Bulk Cacao as Selection Indicator

A problem encountered in plant breeding process to determine bean color quality of fine-flavor cocoa is a long selection period. Preliminary results indicatedthat the fine-flavor cocoa has a low color reflectance than bulk cocoa. The objectiveof this study is to find more applicable and easier method to do the early detectionof fine-flavor cocoa on the breeding population. Detection of the leaf color haracteristics was done by chromatographic and spectrophotometry analysis. hromatographic analysis was carried out in Kaliwining Experimental Station, IndonesianCoffee and Cocoa Research Institute using complete random design consistedof two types of cocoa; fine-flavor (10 clones) and bulk cocoa (10 clones). pectrophotometric analysis was conducted at Ma Chung University, Malang, East Java.Four clones of bulk cocoa and six clones of fine flavor cocoa were used in thisanalysis. The results of the study showed that the flush color characteristics of thefine-flavor cocoa were different from the bulk cocoa characteristics as shown bythe differences in the value of L*, b* and anthocyanin content. Flush characteristic s ofthe fine-flavor cocoa had brighter color, more toward green with higher yellowlevel, while the bulk cocoa had darker flush, red and lower yellow level. Thecolor parameter of L* and b* had a higher genetic variation compared with theenvironment variation. However, the parameter a* had a higher environmental variation compared with genetic variation. Grouping of fine-flavor cocoa and bulk cocoacould be done through the detection of flush anthocyanin content, when tendencyof flush anthocyanin content on fine-flavor cocoa was lower than bulk cocoa.The detection of flush color particularly L* and b* parameters through hromatographic analysis and anthocyanin content through spectrophotometric analysismay be used as a criteria for selection the fine flavor cocoa on seedling phase

Sampling Strategy for Space Mean Speed Survey

In most traffic projects, speed survey is required. If the speed survey uses detector, all data might be obtained. Otherwise a sampling strategy needs to be introduced. To ensure the collection of representative sample of speeds there were several sampling options, e.g. collecting sample every regular interval. In this paper three regular intervals were tested, i.e. 30 seconds, 1 minute and 2 minutes 30 seconds. Travel time data was collected in morning, mid day, and afternoon periods in a two-lanes two-ways underpass in Jakarta. Travel speeds were calculated by dividing light vehicle travel times with the underpass length. Space mean speeds were calculated as a light vehicle travel mean speeds/ 5 minutes. The observation of each light vehicle travel times (to get each light vehicle travel speeds) was conducted for the first 15 minutes of three observation periods. More frequent speed sample collection provides higher accuracy