Mapping of the nodulation loci sym9 and sym10 of pea ( Pisum sativum L.)

Several mutants defective in the nodulation process during rhizobial or endomycorrhizal endosymbiosis of pea have been identified previously. We have integrated the map positions of two such nodulation mutations, sym9 and sym10, into the molecular map of pea by applying molecular-marker techniques combined with bulked segregant analysis (BSA). Lines P2 and P54 were found to carry alleles of sym9, line P56 carried an allele of sym10. F2 populations were derived from crosses of P2, P54 and P56, to JI281 and JI15, two of the parental lines that have been used previously to generate a molecular map of pea. sym9 was located on linkage group IV by AFLP-BSA analysis and subsequently mapped by RFLP in both F2 populations, P2 2 JI281 and P54 2 JI281. RFLP-BSA analysis was applied to assign sym10 to linkage group I. The RFLP marker locus, chs2, co-segregates with sym10 in the F2 population of P56 2 JI15.