Difference in net yield between traditional and

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Unformatted text preview: d between traditional and Difference generic generic Example 1 Example Potential yield local variety =4 ton/ hectare Potential Yield generic variety 3 tons/ hectare Damage 50% Bt reduce damage by 100% Yield effect of modified local variety 4 - 4*(1 - .5) = 2 Yield effect of generic variety 3 -2 =1 Productivity: Evidence for Bt Cotton Gains Productivity: Bt cotton in: United States: yield effect 0 – 15% China: yield effect 10% China: South Africa: yield effect 20%-40% India: yield effect 60 – 80 % In every country have reduction in chemical usage Field trials in 2001-2 has yield effect of 80% Field Some Indian Stories Some with generic variety and 87% with local GMV with Pesticides use decline by 70% No wonder yield loss can be 60% In 2002-3 when actual cotton was planted yield In effect was between -10%-30% effect Law pest pressure Law In some locations a wrong variety was introduced The yield gain in 2003-4 was higher-higher pet The damage damage Robin hood and GMV Robin In Gujjarat a local breeder introduced illegally In Bt cotton with spectacular result Bt A unholy alliance of environmentalists and unholy companies wanted the cotton to be burned companies Farmer demonstrated and the cotton saved and Farmer Bt legalized Bt It is meaningless tp speak about yield effect It Bt as insurance Bt since pest damage is a random variable and yield effect varies yield A switch to generic GMV may reduce yield in switch a good year but increase it substantially in a bad one bad Bt...
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