Unexpected Inheritance Pattern of Erianthus arundinaceus Chromosomes in the Intergeneric Progeny between Saccharum spp. and Erianthus arundinaceus

Erianthus arundinaceus is a valuable source of agronomic traits for sugarcane improvement such as ratoonability, biomass, vigor, tolerance to drought and water logging, as well as resistance to pests and disease. To investigate the introgression of the E. arundinaceus genome into sugarcane, five intergeneric F(1) hybrids between S. officinarum and E. arundinaceus and 13 of their BC(1) progeny were studied using the genomic in situ hybridization (GISH) technique. In doing so, we assessed the chromosome composition and chromosome transmission in these plants. All F(1) hybrids were aneuploidy, containing either 28 or 29 E. arundinaceus chromosomes. The number of E. arundinaceus chromosomes in nine of the BC(1) progeny was less than or equal to 29. Unexpectedly, the number of E. arundinaceus chromosomes in the other four BC(1) progeny was above 29, which was more than in their F(1) female parents. This is the first cytogenetic evidence for an unexpected inheritance pattern of E. arundinaceus chromosomes in sugarcane. We pointed to several mechanisms that may be involved in generating more than 2n gametes in the BC(1) progeny. Furthermore, the implication of these results for sugarcane breeding programs was discussed.