Identification and characterization of intergeneric hybrid of commercial sugarcane ( Saccharum spp. hybrid) and Erianthus arundinaceus (Retz.) Jeswiet

To generate drought-tolerant sugarcane, we obtained hybrid lines by the intergeneric hybridization of a Saccharum spp. hybrid with Erianthus arundinaceus. A test using 5S rDNA as a marker identified five intergeneric hybrid lines with a production efficiency of approximately 3 %. There was difficulty in maintaining these hybrid lines because they were weak, and one line only survived. We examined the amount of roots and polyphenol content of the roots, which are related to drought tolerance, in the surviving line. Although the shoot–root ratio, an indicator of the amount of roots, was high in sugarcane and low in E. arundinaceus, the shoot–root ratio of the hybrid line was intermediate between those of the parents. Regarding the polyphenol content of the roots, only the surface of a root sample was stained by NaNO3 in sugarcane, whereas the entire cross section of a root sample was stained in E. arundinaceus. For the hybrid line, the entire cross section of the root was faintly stained. From these results, we concluded that the roots characteristics were introduced by the intergeneric hybridization between a Saccharum spp. hybrid and E. arundinaceus.