6. Insecticidal effects on pollinator’s population and pollen mediated gene flow from transgenic to non-transgenic cotton genotypes

Effectiveness of refuge crop is on risk due to shifting of pollen mediated gene flow by honey bee pollinators.  Pesticides and pollinators both are essential for the high and quality production of many crops. Present studies were therefore carried out to study the pesticide risks on pollinators and the ultimate effect of pollinators on cotton refuge crop. Pollinator population was badly affected in insecticide treated plots with 92 percent reduction over control. Honey bee were the efficient pollinator in cotton and pollen mediated gene flow was recorded as higher as up to 26 percent in absence of any chemical or toxic sprays. Among cultivars VH-290 showed the highest attraction for honeybees and consequently greater gene flow (21.2%) than other varieties because of its unique floral morphology.  Regression analysis of pollinator population per plant and gene flow demonstrated that one-unit increase in pollinator population would increase geneflow @ 6.86% in sprayed field and 7.09% in un sprayed field. It is concluded that we should cultivate refuge non Bt cotton that have minimum chance of gene flow in order to minimize pollen mixing, maintain the quality of the refuge crop and to counter the field evolved resistance of insect pests against pesticides. Keywords: Honey bee; Pollen mediated gene flow; Pesticide risk; Pollinator; Refuge crop http://dx.doi.org/10.19045/bspab.2020.90233