Officials said at least 4,000 delegates from the 36 states and the capital Abuja were expected to vote at the PDP primaries in the oil hub of Port Harcourt, in the heartland of the Niger delta, in an event due to extend to Sunday.
"On behalf of al of us, we congratulate you".
The statement argued that the just-concluded convention had confirmed that democracy in Nigeria can be entrusted in the PDP than the ruling All Progressives Congress (APC), calling on Nigerians to give PDP another opportunity to manage the country.
He said, "Indeed, we have learned our lessons and by this convention, we are now set to forge a new path for our great party and Nigeria".
"All the doubting Thomases that thought we would all walk out after the results have been announced, we are not going anywhere but walking with Atiku to victory".
Former vice President Atiku Abubakar polled over 1000 votes, thereby beating other aspirants to clinch the ticket to be the party's flag bearer in next year's presidential election.
The Governor also stated that no single person can influence the outcome of the national convention.
Port Harcourt streets had been festooned with conference banners, while police said thousands of officers were deployed to the PDP primary.
"Thank you for choosing me", Abubakar said on Twitter.
It is not a one man's job, it is one of collective responsibly, he added.
"Let me also commend my fellow competitors for displaying a sense of unity, a sense of objective and a sense of commitment".
The national chairman also promised Nigerians an all-inclusive government if the party's candidate is elected as president.
"As you can see that we had a very successful convention and we are all delighted to support President Muhammadu Buhari in his quest for a second term".
Mr Abubakar is expected to be the main challenger to Mr Buhari in the 2019 presidential election.