MOLECULAR MARKERS SHARED BY DIVERSE APOMICTIC PENNISETUM SPECIES

Two molecular markers, a RAPD (randomly amplified polymorphic DNA) and a RFLP/STS (restriction fragment length polymorphism/sequence-tagged site), previously were found associated with apomictic reproductive be havior in a backcross population produced to transfer apomixis from Pe nnisetum squamulatum to pearl millet. The occurrence of these molecula r markers in a range of 29 accessions of Pennisetum comprising II apom ictic and 8 sexual species was investigated. Both markers were specifi c for apomictic species in Pennisetum. The RFLP/STS marker, UGT 197, w as found to be associated with all taxa that displayed apomictic repro ductive behavior except those in section Brevivalvula. Neither UGT197 nor the cloned RAPD fragment OPC-04(600) hybridized with any sexually reproducing representatives of the genus. The cloned CO4(600) was asso ciated with 3 of the 11 apomictic species, P. ciliare, P. massaicum, a nd P. squamulatum. UGT197 was more consistently associated with apomic tic reproductive behavior than OPC04(600) or cloned C04(600) thus it c ould be inferred that UGT197 is more closely linked to the gene(s) for apomixis than the cloned C04(600). The successful use of these probes to survey other Pennisetum species indicates that apomixis is a trait that can be followed across species by using molecular means. This te chnique of surveying species within a genus will be useful in determin ing the relative importance of newly isolated markers and may facilita te the identification of the apomixis gene(s).