(Reuters) - Monsanto Co (>> Monsanto Company), the world's largest seed producer, has approached Bayer AG (>> Bayer AG) to express interest in its crop science unit, including a potential acquisition worth more than $30 billion (20.7 billion pounds), according to people familiar with the matter.

The move underscores Monsanto's unabated expansion drive after Switzerland's Syngenta AG (>> Syngenta AG) rejected its takeover approaches last year and agreed earlier this year to be acquired by ChemChina for $43 billion.

It also illustrates Monsanto's determination to further consolidate its industry, as the global seed and crop protection market continues to suffer from high inventories and low prices for agricultural commodities.

Monsanto executives met in Chicago recently to discuss the company's interest in Bayer's agricultural assets, the sources said this week. Monsanto sees valuable synergies between its seed business and the crop protection assets of Bayer, the sources added.

Among the possibilities discussed were an outright acquisition of the crop science unit and a joint venture or other type of partnership between the two companies, the sources said. These talks were preliminary, and another meeting between the two sides has been scheduled for April, the sources added.

Bayer has been holding the talks with Monsanto to probe its interest, the sources said. The German company currently has no plans to actively pursue a sale of its crop science division, the sources added.

The sources asked not to be identified because the discussions were confidential. Monsanto and Bayer declined to comment.

Bayer’s crop science division has businesses in seeds, crop protection and non-agricultural pest control. It had sales of 10.4 billion euros ($11.7 billion) in 2015 and posted adjusted earnings before interest, tax, depreciation and amortisation of 2.42 billion euros.

Bayer is the second biggest player in crop chemicals, with an 18 percent market share, just behind Syngenta, which has a 19 percent share. Monsanto is a leader in seeds, with a 26 percent market share, followed by Dupont (>> E I Du Pont De Nemours And Co), with 21 percent. DuPont agreed last year to merge with Dow Chemical (>> Dow Chemical Co).

Bayer said last year it planned to keep its crop chemicals business, saying it was an "integral part" of the German healthcare group. It has said it aims to concentrate on its core brands in crop protection.

It also wants to strengthen its position in its established crops  - cotton, oilseed rape/canola, rice and vegetables – and to establish competitive positions in soybeans and wheat.

(Reporting by Ludwig Burger in Frankfurt and Mike Stone in New Orleans; Additional reporting by Maria Sheahan in Frankfurt and PJ Huffstutter in Chicago; Editing by Leslie Adler)

By Ludwig Burger and Mike Stone