Bt Brinjal The scope and adequacy of the GEAC environmental risk assessment
Bt Brinjal: The scope and adequacy of the GEAC ... - Down To Earth
Bt Brinjal: The scope and adequacy of the GEAC ... - Down To Earth
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Environmental Risk Assessment 292003). IIVR (2007a) can be considered to confirm <strong>the</strong>se previously published results. However, multiple papers have reportedsuccessful hybridisation between brinjal <strong>and</strong> S. violaceum (Box 6). Consequently <strong>the</strong> results in IIVR (2007a) for S. violaceummust be considered anomalous. Taking all <strong>of</strong> <strong>the</strong>se issues into consideration, as a whole, <strong>the</strong> data in IIVR (2007a) are ra<strong>the</strong>runinformative for assessing <strong>the</strong> gene flow <strong>risk</strong>s associated with <strong>Bt</strong> brinjal.Nine species <strong>of</strong> Leptostemonum are known to hybridise with brinjal (Box 6), <strong>and</strong> six <strong>of</strong> <strong>the</strong>se species are known to occur inIndia. Twenty-six species <strong>of</strong> Leptostemonum occur in India, <strong>and</strong> <strong>the</strong> brinjal hybridisation potential for almost 20 <strong>of</strong> <strong>the</strong>se speciesis unknown. Only three <strong>of</strong> <strong>the</strong> 26 species were even considered by EC-II, <strong>the</strong> Dossier, or <strong>the</strong> Supplemental Materials. Thus<strong>the</strong>re was insufficient information for concluding that gene flow <strong>risk</strong>s are low.Needed Experiments <strong>and</strong> ObservationsAdditional analysis <strong>and</strong> experimentation should be conducted so that gene flow <strong>risk</strong>s to o<strong>the</strong>r species <strong>of</strong> Solanum insubgenus Leptostemonum can be adequately assessed (numbering is continued from previous section):2) Identification <strong>of</strong> wild relatives. Additional effort should go into determining if <strong>the</strong>re are more species <strong>of</strong> Leptostemonumthat occur in India. <strong>The</strong> nation’s herbaria should be examined <strong>and</strong> taxonomic experts in <strong>the</strong> group should be consulted.3) Hybridisation. <strong>The</strong> 26 species listed in Box 4, <strong>the</strong> three additional species listed in Box 6, <strong>and</strong> any new species identifiedin <strong>the</strong> previous efforts in 1) should be carefully analysed to determine which species are known not to hybridise with brinjal.4) Overlap. For <strong>the</strong> species that remain from 2), if <strong>the</strong> data exist, <strong>the</strong> timing <strong>of</strong> flowering <strong>and</strong> <strong>the</strong> geographic distributionshould be characterised to determine <strong>the</strong> extent <strong>of</strong> overlap with brinjal.5) Cross-compatibility. For species with overlap (<strong>and</strong> species for which <strong>the</strong> information is insufficient to conclude that <strong>the</strong>reis no overlap), cross-compatibility between <strong>the</strong> species <strong>and</strong> brinjal should be evaluated experimentally using methods that willprovide more accurate estimates <strong>of</strong> successful hybridisation. To include relevant genetic diversity, <strong>the</strong> hybridisation studiesshould use recently collected wild <strong>and</strong> weedy genotypes (not older accessions) from a range <strong>of</strong> habitats <strong>and</strong> geographic areas inIndia (e.g., see Karihaloo <strong>and</strong> Gottlieb 1995), especially regions where brinjal production is concentrated. <strong>The</strong>se experimentsshould be designed to confirm previously published results on successful <strong>and</strong> unsuccessful hybridisation so that <strong>the</strong> data on newspecies can be considered to be reliable. If <strong>the</strong> previous studies cannot be confirmed, it will be necessary to conduct additionalexperiments to explain why. By doing this, <strong>the</strong> data from <strong>the</strong> hybridisation experiments will be more reliable.6) Fitness <strong>of</strong> interspecific hybrids <strong>and</strong> backcrosses. For <strong>the</strong> species in Box 6 <strong>and</strong> any o<strong>the</strong>r species forming fertile hybridswith brinjal, experiments should be conducted to determine <strong>the</strong> relative fitness <strong>of</strong> crosses between <strong>the</strong> hybrids <strong>and</strong> <strong>the</strong> wildparent (this cross is called an F1 backcross). If <strong>the</strong> fitness <strong>of</strong> <strong>the</strong> backcross progeny is greater than <strong>the</strong> F1 hybrid, <strong>the</strong>n <strong>the</strong>species should be considered at <strong>risk</strong> <strong>of</strong> gene flow.7) Gene flow rates. It will probably be a waste <strong>of</strong> time to conduct additional field experiments to estimate gene flowrates from <strong>Bt</strong> brinjal to <strong>the</strong> wild species. It is difficult to obtain unbiased estimates <strong>of</strong> gene flow, <strong>and</strong> for <strong>the</strong> purpose <strong>of</strong> <strong>risk</strong><strong>assessment</strong> it can be assumed that gene flow is high enough to be evolutionarily <strong>and</strong> ecologically meaningful.Finding 12. <strong>The</strong>re is insufficient evidence that wild or weedy relatives <strong>of</strong> brinjal would not obtain a fitness benefitfrom a <strong>Bt</strong> transgene should gene flow occur. <strong>The</strong>re is insufficient evidence that wild relatives <strong>of</strong> brinjal will not sufferreduced genetic diversity from <strong>the</strong> introgression <strong>of</strong> <strong>the</strong> <strong>Bt</strong> transgene. <strong>The</strong>re is insufficient evidence that non-GM brinjalwill remain uncontaminated by <strong>Bt</strong> brinjal.EC-II (page 56, our emphasis) asserts “FSB is a lepidopteran pest that prefers only brinjal <strong>and</strong> cry1Ac provides protectiononly against FSB <strong>and</strong> o<strong>the</strong>r lepidopteran pests. Since no lepidopteran pests are prevalent on Solanum wild species, <strong>the</strong> matter <strong>of</strong>fitness advantage does not arise.” No evidence is provided to substantiate <strong>the</strong>se claims. <strong>The</strong>re are no published studies on <strong>the</strong>arthropod herbivores (including lepidoptera) inhabiting wild populations <strong>of</strong> S. melongena, S. melongena insanum, or S. incanumor any <strong>of</strong> <strong>the</strong> o<strong>the</strong>r wild relatives potentially at <strong>risk</strong> (Box 4 <strong>and</strong> Box 6). Thus, it is possible that some wild relatives <strong>of</strong> brinjalwould gain an advantage from <strong>the</strong> <strong>Bt</strong> transgene.<strong>The</strong> host range <strong>of</strong> BFSB is uncertain. Even if EC-II is correct in that BFSB prefers to feed on brinjal, it is <strong>the</strong> suitablehost range, not <strong>the</strong> preferred host range that is relevant for assessing this <strong>risk</strong>. All things being equal, <strong>the</strong> preferred host will