Chief executive Ian Glasson said he was excited about the partnership.
"Our immediate focus will now move to completing settlement and ensuring a smooth transition to the separate business structures."
Once the deal is done, the slimmed down PGG Wrightson will consist of stock agency, retail and water rural services based entirely in New Zealand.
On Monday, PGG Wrightson announced a board reshuffle with David Cushing among the incoming directors.
Burt and independent directors Bruce Irvine and John Nichol will retire on April 30 and be replaced by Cushing, Rodger Finlay and Sarah Brown. The three appointees are deemed to be independent directors.
Finlay, who is deputy chair of the Cushing-controlled farm manager Rural Equities, will assume Wrightson's chair. He replaces Agria representative Joo Hai Lee, who will be Finlay's deputy.
H&G, the Cushing family's investment vehicle, bought a 2.2 per cent stake from Agria last week, adding 17 million shares to its existing stake of 3.1 million shares. That equates to about 2.7 per cent of Wrightson's shares on issue.
PGG Wrightson shares last traded at 52c, valuing the company at $392m.