EFEK KRONIS TOKSIN Bacillus thuringiensis Cry1A.105 TERHADAP PERTUMBUHAN DAN PERKEMBANGAN Ostrinia furnacalis

FRANSISKA NINGRUM DIAN PUSPITA, Prof. Ir. Y. Andi Trisyono, M.Sc., Ph.D.

2015 | Skripsi | S1 ILMU HAMA DAN PENYAKIT TUMBUHAN

Toksin Bacillus thuringiensis Cry1A.105 merupakan protein toksin yang disisipkan dalam jagung transgenik MON 89034 untuk mengendalikan berbagai jenis hama Lepidoptera. Efek kronis protein B. thuringiensis telah dilaporkan pada beberapa spesies serangga. Penelitian ini bertujuan untuk mengetahui efek toksin B. thuringiensis Cry1A.105 terhadap pertumbuhan dan perkembangan Ostrinia furnacalis. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) dengan tiga perlakuan 0 ppm (kontrol); 0.006 ppm (LC15); 0.049 ppm (LC50) dengan masing-masing empat ulangan menggunakan 120 larva per ulangan. Parameter yang digunakan yaitu mortalitas, Larvae Growth Index (LGI), Standarized Insect-growth Index (SII), abnormalitas, rasio jantan betina, dan indeks Waldbauer. Aplikasi sublethal B. thuringiensis Cry1A.105 menurunkan laju pertumbuhan dan kemampuan larva O. furnacalis dalam mengubah jumlah pakan yang ditelan dan dicerna menjadi substansi tubuh sehingga dapat menghambat perkembangan larva menjadi pupa dan imago. Hal ini diindikasi dari tingginya pakan yang dicerna (AD) (39,65 ± 3,73%) pada larva yang telah terpapar toksin Cry1A.105 dibandingkan dengan kontrol (26.45 ± 2.96%). Disisi lain indeks konsumsi (CI), jumlah pakan yang ditelan menjadi substansi tubuh (ECI) dan jumlah pakan yang dicerna menjadi substansi tubuh (ECD) lebih rendah (27.07 ± 2.15 mg/hari, 2.79 ± 0.30%, 9.43 ± 1.26%, berturut-turut) dibandingkan dengan kontrol (31.05 ± 4.74 mg/hari, 5.49 ± 0.32%, 44.71 ± 19.78%, berturut-turut). LGI dan SII larva yang terpapar memiliki nilai yang lebih rendah (5,62 dan 4,67 ± 0,25) daripada larva LGI dan SII kontrol (7,17 dan 5,85 ± 0,31). Kata kunci : Bacillus thuringiensis, efek kronis, Cry1A.105, Ostrinia furnacalis.

Bacillus thuringiensis Cry1A.105 toxin is one of the proteins expressed in the transgenic corn MON 89034 intended for controlling the Asian Corn Borer (Ostrinia furnacalis). Chronic effects of B. thuringiensis proteins on several insects have been reported. This research was intended to determine the chronic effect of B. thuringiensis Cry1A.105 on growth and development of O. furnacalis larvae. This research employed a Completely Randomized Design (CRD) consisting of three treatments 0 ppm (control); 0.006 ppm (LC15); 0.049 ppm (LC50) and four replications. Each replicate used 120 newly hatched larvae. Parameters used were mortality, Larvae Growth Index (LGI), Standarized Insect-growth Index (SII), abnormality, sex ratio, and Waldbauer indexes. Sublethal aplication of B. thuringiensis Cry1A.105 reduced the growth rate and the ability of larvae O. furnacalis to convert the ingested food into the body substances. It eventualy inhibited the development of larvae to become pupae and adults. Those impacts represented disturbances in the metabolic process of intoxicated larvae. Although Approximate Digestibility (AD) on the larvae exposed to toxins Cry1A.105 was higher (34.23 ± 3.20%) in comparison to the control larvae (26.45 ± 2.96%), they consumed significantly less food as indicated by lower Consumption Index (CI) (27.07 ± 2.15 mg/day) compared to that for the control larvae (31.05 ± 4.74 mg/day). Furthermore, the Efficiency of Convertion of Ingested Food to Body Substance (ECI) and the Efficiency of Corvertion of Digestibility Food to Body Substance (ECD) of intoxicated larvae (2.79 ± 0.30%, 9.43 ± 1.26%, respectively) were less than those of the control (5.49 ± 0.32%, 44.71 ± 19.78%, respectively). Overall, the LGI and SII of the intoxicated larvae (5.62 and 4.67 ± 0.25, respectively) were also lower than controls (7.17 and 5.85 ± 0.31, respectively). Keywords : Bacillus thuringiensis, chronic effects, Cry1A.105, Ostrinia furnacalis.

Kata Kunci : Bacillus thuringiensis, chronic effects, Cry1A.105, Ostrinia furnacalis.