Y mathau hybrid sy'n cael eu defnyddio i gynhyrchu 'Cennin Cymreig' yw'r rhai sy'n fwyaf addas ar gyfer amodau tyfu Cymru. Maent yn cynhyrchu cynnyrch terfynol sydd â'i nodweddion penodol ei hun, megis y prif ddail gwyrdd tywyll sy'n dros 40% o hyd y genhinen.
The hybrid varieties used to produce ‘Welsh Leeks’ are those most suited to Welsh growing conditions. They produce a final product which has its own specific characteristics, such as the predominant long distinctive dark green flag which comprises over 40% of the overall length of the leek.