Syngenta AG may seek partners to help improve its product lineup after a thorough review in the wake of a rebuffed takeover approach from Monsanto Co., the agrichemicals group's chairman told a Swiss newspaper.

Syngenta's board is under pressure from shareholders to show how it plans to generate value after turning its back on Monsanto's $47 billion cash-and-share offer, which it said undervalued the company and had too great an execution risk.

In an interview with Finanz und Wirtschaft, Michel Demare said it was too early to discuss what steps Syngenta planned to boost its results.

But he added: "We will subject our product portfolio to a total review, especially on the seed side. Then we will see if there are appropriate transactions to improve ourselves, perhaps with partnerships and joint ventures."

Asked about short-term steps it could take, he said: "Some of these things can be done in the short term. But what we do not want is to improve earnings in the short term at the expense of the future. We must remain responsible."

Demare said he had no concerns about activist shareholders and had no immediate plans to try to forge a group of core investors from the company's fragmented investor base.

"But if we made a major acquisition, it would be possible for example to take a major investor on board who co-financed the transaction by purchasing Syngenta shares," he added.

Demare said he took six calls from Monsanto boss Hugh Grant in the first two weeks of August alone and had no idea what Grant planned next.

Some Syngenta investors have expressed dismay that the company did not at least open talks with Monsanto. "For me it is clear that the chairman did not behave as many shareholders would have wished," FuW quoted Artisan Partners fund manager Richard Logan as saying.

Demare acknowledged Syngenta had to "explain ourselves, regain trust and deliver results" but also dismissed as "illusion" the offer price of 449 Swiss francs and then 470 francs per share that Monsanto said it had proposed. He noted the 18 months it would have taken to wrap up any deal.

Syngenta shares fell 18 percent on news Monsanto was abandoning its approach and closed on Friday at 323.70 francs.

Demare noted the stock was slightly above the level it was when Monsanto emerged as a suitor, while rivals' shares were down by as much as a fifth.

He said Syngenta's cost-cutting program was ahead of plan but could be expanded should it find more room to cut.