Identification of BC_2 Progeny from Saccharum officinarum × Erianthus arundinaceus by ISSR Markers

Erianthus arundinaceus (Retz.) Jeswiet is of great interest as a germplasm source to sugarcane breeders for its good ratoon ability, tolerance to environmental stress, disease resistance and vigor. Many attempts were performed to introduce these characters into modern sugarcane cultivars, and great progress has been made. In this paper, a microsatellite-based technique, viz. inter-simple sequence repeat (ISSR), was used to identify genuine hybrids from some putative BC2 clones, which come from E. arundinaceus (Retz.) Jeswiet. Thirty ISSR markers were screened using the two parental templates DNA in each cross. The markers, which produced parents' specific bands or only paternal-specific band(s), were used to detect the putative BC2 clones. A total of 164 putative BC2 clones, selected from 10 crosses between sugarcane cultivars (Saccharum spp.) and E. arundinaceus-derived BC1 progenies (designated as YCE 01 series), were tested. The results showed that 160 genuine hybrids were identified as E. arundinaceus descendants, of which 138 hybrids have both parents' specific bands, and the rest just have the paternal-specific band(s). Only 4 clones, derived from 2 crosses, were not genuine hybrids in the present research. As a whole, 2 ISSR markers would be enough to identify the genuine hybrids in most crosses, while in other crosses, fewer, even only one marker. This is the first verification of BC2 progenies from E. arundinaceus × sugarcane cultivars with ISSR markers. This study showed the usefulness of ISSR markers for marker-assisted selection of true cross progeny in the conventional crossing procedure.