Thursday, May 19, 2016

GMO Roundup Resistant Crops

GMO Roundup Resistant Crops --- ===

http://sitn.hms.harvard.edu/flash/2015/roundup-ready-crops/
Why Roundup Ready Crops Have Lost their Allure

do not have to go into detail about probabilities to assess whether superweeds will form – we already have confirmation that they have. Twenty-four cases of glyphosate-resistant weeds have been reported around the world, 14 of which are in the United States [7]. Farmers are now back to tilling their farmlands and spraying more toxic herbicides in addition to Roundup in an attempt to control the superweeds spreading across their farmlands [8]....  The environmental benefits – reduced tilling and reduced use of more toxic herbicides – are fading because the weeds Roundup was supposed to control have sprung up in revolt.

Summary: In the history of agriculture, no technology has been adopted so quickly and completely as genetically engineered crops. Particularly useful crops are ones that have an engineered resistance to herbicides. These crops have alluring benefits: reduced crop damage when herbicides are sprayed, easier weed management, and even the potential for environmental benefits. So what’s the problem? Herbicide-resistant weeds. The benefits gleaned from these crops begin to disappear as these superweeds gain prominence on farmlands across world. However, to fully appreciate the current predicament, it is necessary to understand what led to the difficult problem of superweeds. And it starts with the most common herbicide used in agriculture: Roundup.


Roundup and the crops that resist it

Chances are you’ve heard of Roundup, a common weed killer used by farmers and homeowners alike. Roundup is the brand name for the herbicide, glyphosate. Glyphosate works by preventing plants from being able to make the proteins they need to survive. Since virtually all plants make these essential proteins the same way, glyphosate affects nearly all plants. For this reason, glyphosate is deemed a “broad-spectrum” herbicide [1].

Of course, this is a double-edged sword. While Roundup is a great weed killer, its broad-spectrum effects make it a decent crop killer, too. That’s no good. If our crops aren’t resistant to Roundup, can we figure out a way tomake them resistant? In fact, the agriculture company Monsanto did just that. [snip]

 results show that farming practices associated with Roundup Ready crops actually have a lower environmental impact.

One reason for this is that they are able to reduce their pesticide use and replace more harmful pesticides with glyphosate [1]. The harmfulness of a pesticide is assessed by exposing organisms to higher and higher concentrations of the pesticide until it appears to inhibit their ability to survive. Glyphosate is considered less harmful because much higher concentrations are required to hurt aquatic animals and plants than with other herbicides [5]

 early as the 1960s, scientists have known that the tactic of only spraying one pesticide has strong potential to push weeds to develop resistance to it. Resistance to an herbicide occurs when one weed has a mutation that allows it to survive a Roundup sprayin

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