Alloployploid breeding
At the polyploid level, breeding is the same as for a diploid. The only difference is that because the chromosome number is high, there is more potential for progress via re-assortment. Sugar cane has a 2n chromosome number of 100 to 130 (barley has 14, rice has 24 ...).
Introgression is possible from diploid ancestors in the same way as for allopolyploids.
A well-known example is the Brassicas:
Brassica spp. polyploid relationships ("U's triangle")
B. nigra, oleracea and campestris are all diploid
B. napus, juncea and carinata are all tetraploid