<P> As of 2014, there have been a few MSV - tolerant cultivars released in Africa . A private company Seedco has released 5 MSV cultivars . </P> <P> US Environmental Protection Agency (EPA) regulations require farmers who plant Bt corn to plant non-Bt corn nearby (called a refuge) to provide a location to harbor vulnerable pests . Typically, 20% of corn in a grower's fields must be refuge; refuge must be at least 0.5 miles from Bt corn for lepidopteran pests, and refuge for corn rootworm must at least be adjacent to a Bt field . </P> <P> The theory behind these refuges is to slow the evolution of resistance to the pesticide . EPA regulations also require seed companies to train farmers how to maintain refuges, to collect data on the refuges and to report that data to the EPA . A study of these reports found that from 2003 to 2005 farmer compliance with keeping refuges was above 90%, but that by 2008 approximately 25% of Bt corn farmers did not keep refuges properly, raising concerns that resistance would develop . </P> <P> Unmodified crops received most of the economic benefits of Bt corn in the US in 1996 - 2007, because of the overall reduction of pest populations . This reduction came because females laid eggs on modified and unmodified strains alike . </P>

Where was the genetic traits obtained for corn