The schematic sketch of "U” triangle presents the production strategy of polyploid hybrids from one-way crosses of diploid and tetraploid parent (wf9, Twf9 and 9475) . The maize and Z. perennis cytoplasm are represented by light green and light pink circles, respectively. The dense green and dense pink strips represent maize and Z. perennis chromosomes, respectively and central red marks represents centromere of both types of chromosome