South Australia will extend its ban on genetically modified crops, keeping the market in the two biggest grain-growing states closed to Monsanto Co. and Bayer AG. […..] The decision restricts an avenue for expansion in Australia, the world’s third-largest canola exporter, for Monsanto and Bayer that was opened when Victoria and New South Wales ended four-year bans on genetically modified canola crops in November. Western Australia, the biggest grain producer, said last year it won’t remove the ban. [...] ”There is no immediate need to give the go ahead for what would have been only a small number of growers wanting to grow crops from the two GM canola seeds developed by companies, Monsanto and Bayer,” McEwen said.