Analysis of the genitor origin of an intergeneric hybrid clone between and for forage production by McGISH.

In this study, the chromosome number and composition of a novel perennial forage crop, 'Yucao No. 6' (Yu6), was revealed by chromosome spread and McGISH (multicolor genomic hybridization) techniques to clarify its genitor origin. Cytogenetic analysis showed that Yu6, which has 56 chromosomes, is an aneuploid representing 12, 17 and 27 chromosomes from ssp. L. (Zm, 2n = 2x = 20), L. (Td, 2n = 4x = 72), and (Hitchc.) Reeves & Mangelsd. (Zp, 2n = 4x = 40), respectively. This finding indicates that Yu6 is the product of a reduced egg (n = 36 = 12Zm + 17Td + 7Zp) of MTP (a near-allohexaploid hybrid, 2n = 74 = 20Zm + 34Td + 20Zp) fertilized by a haploid sperm nucleus (n = 20Zp) of . Moreover, 3 translocated chromosomes consisting of the maize-genome chromosome with the segment of were observed. These results suggest that it is practical to develop perennial forage maize by remodeling the chromosomal architecture of MTP offspring with as a pollen parent. Finally, the overview of forage breeding in the and genera was discussed.