What is "grynner"

Grynner (rhymes with "miner", real name Macdonald Blenman) is a popular calypsonian from Barbados. Like his compatriot Mighty Gabby, his songs often feature political and social commentary. He has been named the Barbados Crop Over Road March "Tune of the Crop" winner seven times (1983–85, 1988–90, and 1998).