Dampak Tanaman Transgenik Bt Terhadap Populasi Serangga Pengendali Hayati

An alternative technique to improve plant resistance to insect pests is plant transformation using the genetic engineering technology. Several transgenic plants resistant to insect have been produced and commercially released to environment in some industrial and developing countries. Before release, transgenic plants need to be assessed for their potential risks to human health and environment. One of the environmental risk assessments is the potential risk to non-target insects, including the biocontrol insects. Laboratories, glasshouse, and field experiments have been conducting the study of the impact of transgenic plant resistance to insect, especially transgenic Bt plants to the population of predators and parasitoids. However the results were controversial. The objective of this review is to inform some of controversial results, and to suggest serial experiments need to be done to solve the problem. The impact of the transgenic plant resistance to insects depends on several factors, such as genes that are used to transform the plants, the kind of plant pests, and the kind and stages of the insect natural enemies. Results of the experiments were influenced by sites of the experiments (laboratory, glasshouse, or field) and contact of the natural enemies to the toxin. Some experiments showed that the transgenic Bt plants have no impact to the natural enemies population, and otherwise. Due to the controversial results, the experiment and assessment should be done in depth and carefully studied. A sequential experiments need to be adopted to avoid the misleading interpretation, and the assessment need to be based on a case by case study

Pengelompokan Dan Struktur Populasi Parasitoid Telur Trichogrammatoidea Armigera Pada Telur Helicoverpa Armigera Pada Jagung Berdasarkan Karakter Molekuler

The effectiveness of this parasitoid was influenced by its population structure in the field. However, because this parasitoid has a tiny size, it was difficult to know the population structure of this parasitoid. This problem can be overcome by using molecular characteristic i.e. molecular markers. Based on RAPD-PCR analysis from 4 selected primers on 19 DNA samples from 3 different locations it was fond, that Gunung Bunder II population was divided into sub-population and so did Cugenang population, which is indicated by their small Fst and Nm index. The Fst and Nm index for Gunung Bunder II population was 0,39 and 0,77, while 0,51 and 0,47 for Cugenang population. If we calculated the Fst and Nm for all samples together, we found that this parasitoid has a random mating pattern, which is also shown by the dendrogram. The dendrogram indicate that each sub- opulation from one location was not grouped in one cluster but distributed in every cluster

Struktur Populasi Trichogrammatoidea armigera, Parasitoid Telur Helicoverpa armigera, Berdasarkan Analisis RAPD-PCR

Population Structure of Trichogrammatoidea armigera,Egg Parasitoid of Helicoverpa armigera Based on RAPDPCRAnalysis. Bahagiawati, Damayanti Buchari, Nurindah,H. Rizjaani, Dwinita W. Utami, B. Sahari, and A.Sari. Genetic structures of Trichogrammatoidea armigera(Hymenoptera: Trichogrammatidae), the egg parasitoid ofHelicoverpa armigera (Lepidoptera: Noctuidae) were studied.Egg masses of H. armigera were collected from fields ofseveral locations in West Java and East Java with differentdistances among them and two distinct cultural practices,i.e., monoculture and polyculture. Genetic relationshipsamong T. armigera populations that emerged from the collectedH. armigera eggs were analysed by the RAPD-PCRtechnique using four oligonucleotide primers. The fourprimers revealed 55 presumptive polymorphic loci that wereused to estimate the population structures. The estimatedvalues of Fixation Index (Fst) was 0.16, indicating that therewas a division of the populations into subpopulations. ThisFst value implied the present of reproductive isolationamong the populations that might be due to their lowmigration rate (1.3 insect per generation). This low migrationrate indicated the present of low level of gene flow amongthe populations. A dendrogram resulted from the NTSYSanalysis indicated that the West Java and East Java populationsof the egg parasitoid had quite wide genetic distances,while within each of the populations there was a subdivisionof minor populations. This finding has an important implicationon the program to release Trichogramma spp. as a biologicalcontrol agent. The release of the parasitoid cannot bedone randomly, because if we pick up a minor population,the starter or the released population will mate with thelocal population and multiply, thus the inundation will fail tocontrol the target pest