The one-day competition, founded in 1983, has absorbed the 18 first-class board XIs, minus Glamorgan plus Huntingdonshire, and has been split into eight qualifying groups.
The reforms also extend to the championship, where each minor county will play three of their nine games under 'grade' rules two-day, one-innings matches of 120 overs apiece.
The MCC Trophy, which retains the carrot of a Lord's final, is now a 60-overs event, not 55. Sunday's opening fixtures are in the South-West, Devon meeting Dorset at Budleigh Salterton and Cornwall playing Somerset at Taunton.
MCC TROPHY.- Gp A: Cornwall, Devon, Dorset, Gloucs, Somerset. Gp B: Bucks, Berks, Hants, Kent, Sussex. Gp C: Beds, Herts, Middlesex, Surrey. Gp D: Hereford, Wales, Warwicks, Wilts, Worcs. Gp E: Huntingdon, Leics, Notts, Oxon, Staffs. Gp F: Cheshire, Cumberland, Derbys, Lancs, Shrops. Gp G: Cambs, Essex, Norfolk, Northants, Suffolk. Gp H: Durham, Lincs, Northumberland, Yorks. Group winners qualify for the qtr-finals.