"We've had a very strong summer followed by the Test series victory in the West Indies where a number of younger players put their hands up for consideration.
"Two of those integral to the series win in the West Indies were spinners Ish Sodhi and Mark Craig. While we accept that Mark and Ish are by no means the finished product, they are promising bowlers that we want to invest time in."
Edgar says that with a full tour against Pakistan in the United Arab Emirates coming up it was critical to select two Test spinners. The year ahead also features a tour to England, a full tour by Sri Lanka, and short visits by South Africa and Pakistan in preparation for the major prize - the ICC Cricket World Cup co-hosted by New Zealand and Australia.
Also new to the contracted group are pacemen Milne and Henry who performed well when given the opportunity in limited overs matches last summer.
"Adam and Matt are two exciting young bowlers that if we manage well have got a big future in all forms of the game."
The addition of Neesham and Ronchi rewards their contributions over the past year, says Edgar.
"Jimmy and Luke are both consistent members of our shorter form teams and they've recently been selected in our Test squad as well.
Edgar says there was not enough certainty to offer Black Caps contracts to two opening Test batsmen - instead just Tom Latham was confirmed in the 20.
"There'll be plenty of opportunities for the openers and others with domestic contracts to put their hand up on both the New Zealand A tour to England later this month and throughout the season in the domestic competitions."
The first round of Major Association contracts will be announced on 25 July.
The 20 players offered BLACKCAPS contracts for the year 1 August 2014 to 31 July 2015 are as follows:
Corey Anderson - Northern Knights
Trent Boult - Northern Knights
Mark Craig - Otago Volts
Martin Guptill - Auckland Aces
Matt Henry - Canterbury
Tom Latham - Canterbury
Mitchell McClenaghan - Auckland Aces
Brendon McCullum - Otago Volts
Nathan McCullum - Otago Volts
Kyle Mills - Auckland Aces
Adam Milne - Central Stags
Colin Munro - Auckland Aces
Jimmy Neesham - Otago Volts
Luke Ronchi - Wellington Firebirds
Ish Sodhi - Northern Knights
Tim Southee - Northern Knights
Ross Taylor - Central Stags
Neil Wagner - Otago Volts
BJ Watling - Northern Knights
Kane Williamson - Northern Knights