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

Environmental Risk Assessment 23Gene Flow and Its ConsequencesConclusion 5. Brinjal has considerable valuable genetic diversity in India that could be threatened by geneflow. EC-II, the Dossier, and the Supplemental Materials are inadequate for concluding that Bt brinjal has nosignificant effects on the biological diversity or weediness of brinjal or its wild relatives.Brinjal has many local varieties and wild relatives in India that could be threatened by gene flow from Bt brinjal. India is theworld’s centre of biological diversity of brinjal (land races, cultivars, door-yard plants, etc.), with over 2500 local varieties known.Brinjal has at least one conspecific wild relative in India can introgress with brinjal, S. melongena var. insanum. Brinjal also hasseveral heterospecific wild relatives in India that can hybridise with brinjal. Thus, the potential threat to the genetic diversity ofbrinjal and its wild relatives and the potential weediness of brinjal and its wild relatives must be assessed. EEII, the Dossier,and the Supplemental Materials suggested that cultivated brinjal does not form wild populations and gene flow among brinjalpopulations and from cultivated brinjal to its wild relatives is so low that the risks associated with gene flow are negligible. Asdetailed below, the data presented are inadequate for concluding that these risks are negligible.Finding 10. It is highly likely that cultivated brinjal (Solanum melongena), including local varieties and landraceshave crossed with feral populationsof S. melongena, and it is possibleBOX 3that cultivated varieties can revertWhy the experimental gene flow estimates from Bt brinjalto wild phenotypes and establishmay be underestimatedferal populations. Therefore, thepossible effects of intraspecific gene A. The flowering times of the Bt brinjal and the surrounding non-Bt brinjalflow from Bt brinjal to other varieties were not coincident. Relevant data to determine the degree of coincidenceand populations of brinjal should be were not provided.examined.B. The location of the honeybee colonies at the corners of the Bt brinjalEC-II and the Dossier assert thatplot may enable bees to take very short inter-plant movements to harvestbrinjal does not form volunteer orsufficient pollen and/or nectar, thereby underestimating the degree of geneferal populations. This assertion isflow (most inter-plant movements would be among Bt brinjal plants ornot adequately demonstrated, and itamong non-Bt brinjal plants rather than between Bt and non-Bt brinjalis quite possible that brinjal can form plants). By positioning the colonies farther away, bees would have toferal populations in India. Working in move farther to find the plot, and then might be more likely to movesouthern India, Deb (1989) noted that more frequently between Bt and non-Bt plants, resulting in high rates of“feral forms [of brinjal] are sometimes outcrossing.found.” Indeed, wild populations of S. C. Slight differences in flower morphology between the Bt and non-Bt brinjalmelongena are known to occur in India might lead bees to specialise foraging on one or the other (but not both),(Choudhury 1995; Sekara et al. 2007). leading to underestimated levels of gene flow.Therefore additional studies are needed D. Native pollinators may be more efficient pollinators of brinjal thanto determine the extent of these wildhoneybees. Most solanaceous species, such as brinjal, are more effectivelypopulations and their weediness. Inpollinated by buzz pollinators than by honeybees. If these native pollinatorsaddition, the possibility that Bt brinjal were absent or rare, gene flow would be underestimated.is able to revert to a wild or weedyphenotype must be examined, because the Bt transgene could spread rapidly by this means into other natural populations of S.melongena and transfer the Bt transgene to many local brinjal varieties.Additional studies on the potential reversion of brinjal cultivars to wild and weedy phenotypes should be conducted. Thesecould be conducted on the parental varieties to Bt brinjal. It is important to evaluate progeny past the F1 generation, as rapid