It's going to take a lot of money to woo the world's largest supplier of genetically modified seeds.

More than $62 billion.

Multinational pharmaceutical company giant Bayer AG found that out the hard way this week, after their hefty offer – valued at $122 a share – was rejected by agrochemical giant Monsanto, despite declining prices for major crops over the past three years and dwindling incomes for seed companies.

Monsanto CEO and chairman Hugh Grant called Bayer's bid "incomplete and financially inadequate", saying "the current proposal significantly undervalues our company and also does not address or provide reassurance for some of the potential financing and regulatory execution risks related to the acquisition."

Bayer says it will continue to pursue Monsanto, and Monsanto says they are open to further negotiations with the pharmaceutical company.

If all goes according to previous trends, Bayer would abandon the Monsanto name after the purchase, giving Monsanto a clearer path to overcoming public backlash against their genetically modified seeds.

In the wake of Monsanto rejection, Bayer's shares fell 5.6 percent to 84.47, the lowest since October 2013.

Bayer's broad portfolio of products includes over a dozen insecticides and herbicides. If they acquire Monsanto, Bayer will become the world's largest supplier of seeds and agricultural chemicals.

Read More:

• Monsanto rejects Bayer bid, but open to more talks (Reuters)
• Bayer's $62 million Monsanto Bid Raises Alarm on Final Price (Bloomberg)
• Â Monsanto Rejects Bayer Merger Offer, Says Its Open to Talks (Wall Street Journal)