Bt Brinjal The scope and adequacy of the GEAC environmental risk assessment

52 Bt Brinjal: The GEAC environmental risk assessmentThese values for the yield benefit of Bt brinjal are significantly less than thosesuggested by Mahyco and EC-II.The main reasons for this are that (1) Mahyco and EC-II did not consider how EE-1 Bt brinjal would be compatible withpresent brinjal production systems,and (2) they assumed that yieldsTable 4. Estimated expected maximum yield benefit from hybrid Bt brinjal to farmers inIndia based on a comparison to a similar non-Bt brinjal hybrid without any control ofobtained under controlled experimentalBFSB, using data from the MST and LST, yield gaps, and other factors related to Indianconditions accurately estimated yields production systems described above.on farm and ignored the scientificLocation Size of farm Proportion Maximum potentialliterature on yield gaps. Moreover, theyof farmers yield benefit (q/ha)did not adjust their estimates to reflectMST LSTtheir own data. Their estimates areWest Bengal, Mostly small-scale0.61 0 0based on the MST data. The newer Orissa, Bihar resource-poorLST data shows significantly lower Rest of India Large-scale commercial 0.04 84.2 43.7potential yield benefits from EE-1 Btbrinjal, yet their estimates have notbeen adjusted downward.Rest of India Small-scale resource-poor 0.35 13.9 7.2Even so, the low estimates presented here are likely to overestimate the actual yield benefits to India as a whole because itis unlikely that all farmers will adopt EE-1 hybrid Bt brinjal technology. There are three factors that may limit adoption. Asdiscussed above, hybrid Bt brinjal may not fit well with some of the large-scale commercial production systems that presentlyrely on open-pollinated varieties (OPVs), and is unlikely to fit into small-scale resource-poor production. In addition, hybridBt brinjal may be too costly for some farmers to afford to use. Lastly, the yield risk of using hybrid Bt brinjal may deter manyfarmers from adopting it. About 16% of the field trials showed hybrid Bt brinjal having no yield advantage over non-Bt brinjaleven when non-Bt brinjal had no control of BFSB. Many farmers are risk-averse and may not adopt hybrid Bt brinjal if the riskof no benefit is too high.In addition, the estimates are likely to be overestimates because the relevant control comparison for farmers is the Btvariety against the best non-Bt variety being used in a region. The control comparison used in the MST and LST was the Btvariety against a genetically similar non-Bt variety. The best non-Bt variety in a region is expected to have higher yields than agenetically similar non-Bt control variety used in the MST and LST experiments, and this also will reduce the estimated yieldbenefit of hybrid Bt brinjal. This serves to reiterate previous points about the limitations of the data from the MST and LSTexperiments. One should expect a large yield gap and refrain from making any inferences about which hybrid Bt brinjal varietyis best in a region.The MST and LST were designed to answer the narrow question: how much does the EE-1 Bt transgene, by itself and allother things being equal (the ceteris paribis assumption), improve agronomic performance. This is not the relevant questionfor a farmer. A farmer is interested in whether hybrid Bt brinjal will “improve” things compared to what the farmer ispresently doing. For farmers, all things are not equal, and the concern is a comparison of brinjal varieties (often under unequalconditions), not merely the effect of the transgene. The narrow framing of the MST and LST limits the broader applicability ofthese data to problems of interest to the farmer or the Indian government.Finding 26. Insecticide use might decline in large-scale commercial Bt brinjal production systems by an average of6.5 applications. However, other factors may modulate this substantially, and new secondary pests will result in moreinsecticide use. It is not possible to estimate how insecticide use might change if Bt brinjal were used by small-scaleresource-poor farmers.Another expected advantage of Bt brinjal is a reduction in insecticide use. A reduction in the need for insecticide