Board Thread:Dragon City Questions and Answers/@comment-203.118.242.186-20130405133140/@comment-3271569-20130406104529

Nop, there's is no combination where you have 100% chance to result one. However it's close. I'm not sure about gummy but: So in fact if you breed him with a element that will give less results your chance can increase. It in fact all depense on the dificulty. If gummy is listed in dificulty 2 you will need to try to get 230-299 rating for the best results. However since we don't known if gummy is listed in dificulty 3 it's better to get your rating as high as possible.
 * Electric Dragon (dificulty 3)
 * Nature Dragon (dificulty 1)
 * Gummy Dragon (dificulty 2 or 3 ??)