RFLP MAPPING USING NEAR-ISOGENIC LINES IN THE SOYBEAN [GLYCINE-MAX (L) MERR]

A molecular marker analysis of a near-isogenic line (NIL), its donor parent (DP), and its recurrent parent (RP) can provide information about linkages between molecular markers and a conventional marker introgressed into the NIL. If the DP and RP possess different alleles for a given molecular marker, and if the NIL possesses the same allele as the DP, then it is reasonable to presume a linkage between that molecular marker and the introgressed marker. In this study, we examined the utility of RFLPs as molecular markers for the NIL gene-mapping approach. The allelic status of fifteen RFLP loci was determined in 116 soybean RP/NIL/DP line sets; 66 of the 'Clark' RP type and 50 of the 'Harosoy' RP type. Of the 1740 possible allelic comparisons (116 NILs x 15 RFLP loci), 1638 were tested and 462 (33.9%) of those were informative (i.e., the RP and DP had different RFLP alleles). In 15 (3.2%) of these 462 cases the NIL possessed the DP-derived RFLP allele, leading to a presumption of linkage between the RFLP locus and the introgressed conventional marker locus. Two presumptive linkages, pK-3 - r and pK-472 - Lf1, were subsequently confirmed by cosegregation linkage analysis. Although not yet confirmed, two other associations, pk-7 - ab and pK-229 - y9 seemed to be plausible linkages, primarily because the pk-7 - ab association was detected in two independently derived NILs and both markers of the pK-229 - y9 association were known to be linked to Pb. The data obtained in this investigation indicated that RFLP loci were useful molecular markers for the NIL gene-mapping technique.