* BASF to pay for Bayer assets with cash
* To take on more than 1,800 employees as part of deal
* Bayer sells assets to gain approval of Monsanto deal
* Transaction conditional upon Monsanto deal going through
* Shares in BASF fall, Bayer rises (Adds further details of transaction, Bayer comments on Monsanto deal, share prices)
FRANKFURT, Oct 13 (Reuters) - BASF has agreed to buy significant parts of Bayer's seed and herbicide businesses for 5.9 billion euros ($7 billion) in cash, the two companies said on Friday.
BASF, the world's third-largest maker of crop chemicals, has so far avoided seed assets and instead pursued research into plant characteristics such as drought tolerance, which it sells or licenses out to seed breeders.
But Bayer's $66 billion deal to buy Monsanto has created opportunities for rivals to snatch up assets it must sell to satisfy competition authorities.
"With this investment, we are seizing the opportunity to acquire highly attractive assets in key row crops and markets," BASF Chief Executive Kurt Bock said in a statement.
"It will be a strategic complement to BASFs well-established and successful crop protection business as well as to our own activities in biotechnology," he said.
The sale of the LibertyLink-branded seeds and Liberty herbicide businesses, which generated around 1.3 billion euros of sales in 2016, is a key part of the assets Bayer must sell.
It said it would use the proceeds of the sale to partially refinance the planned acquisition of Monsanto, which it still hopes will close in early 2018.
Bayer said it would provide an update on expected synergies from the acquisition when the deal closed, at the latest.
As part of the asset sale to BASF, which is conditional upon the Monsanto acquisition going through, more than 1,800 staff located primarily in the United States, Germany, Brazil, Canada and Belgium will transfer to BASF.
As part of the agreement, BASF has committed to maintaining all permanent positions, under similar conditions, for at least three years after the deal closes, Bayer said.
BASF will also acquire Bayer's manufacturing sites for glufosinate-ammonium production and formulation in Germany, the United States, and Canada, seed breeding facilities in the Americas and Europe as well as trait research facilities in the United States and Europe.
Shares in Bayer rose 0.7 percent to the top of Germany's blue-chip DAX index in pre-market trade at brokerage Lang & Schwarz. BASF fell 0.9 percent to the bottom of the DAX.
($1 = 0.8442 euros) (Reporting by Maria Sheahan; Editing by Stephen Coates and Adrian Croft)