A GENETIC-MAP OF THE APOSPORY-REGION IN BRACHIARIA HYBRIDS - IDENTIFICATION OF 2 MARKERS CLOSELY ASSOCIATED WITH THE TRAIT

The objective of this work was to identify molecular markers tightly l inked to the gene controlling apospory in a hybrid population derived from a cross between apomictic Brachiaria brizantha and sexual Brachia ria ruziziensis. Since a maize chromosome 5 linkage group had previous ly been associated with the apomixis locus in Brachiaria we used twent y-five RFLP clones that map in detail maize chromosome 5 to cover syst ematically all syntenic regions of the hybrid genome. Forty-six AFLP m arkers were also generated. Three RFLP markers (detected by rz567, rz2 73, and cdo507) and two AFLP markers (PAM52-5 and PAM49-13) appeared t o be related to the ape-region. Segregation data, together with previo usly reported data (corresponding to RFLP markers umc147, umc72, csu13 4, csu149 and RAPD marker OPC4) were used to generate a complete map o f the region. Markers PAM52-5 and PAM49-13 were located respectively a t 1.2 cM and 5.7 cM either side of the target locus. The map shows clo se synteny to regions of maize chromosome 5 and rice chromosome 2.