There's some merger-and-acquisition drama sweeping the agriculture sector today, as Corn Products International (CPO: sentiment, chart, options) announced that its board has withdrawn support for the company's planned buyout by Bunge Ltd. (BG: sentiment, chart, options) . A sharp plunge in Bunge's share price seems to have spooked CPO; the deal was proposed back in June as an all-stock exchange. Now, BG is trading some 28% south of the bid's original value.

Alberto Weisser, CEO of Bunge, stated that "We are disappointed by the Corn Products Board's decision." Under the terms of the agreement, Bunge could continue to force a vote of CPO shareholders, or it could seek $10 million in expenses related to the deal.

Analysts at Citigroup, on the other hand, have cheered CPO's decision. The brokerage firm just upgraded the stock from "hold" to "buy," boosted its price target from $27 to $35, and added CPO to its "top picks live" list as a preferred small-cap idea. The analysts noted that the merger deal looks about "95% dead" following today's news.

As midday approaches, CPO is up about 3%, while BG shares are down 2.7%.