For developing molecular markers linked to white rust resistance in chrysanthemum, RAPD and AFLP were carried out in ‘Puma White’ x ‘Dancer’ mapping population through Bulked Segregant Analysis (BSA) methods. 10 resistant and 10 susceptible individuals were selected and bulked. And then, these bulks were screened using 280 RAPD primers (10 mer) with two parents. As a result of BSA-RAPD, 25 Dancer/R-bulk specific bands in 21 primers and 22 Puma White/S-bulk specific bands in 18 primers were selected. These resistant or susceptible specific bands were screened in 10 resistant and 10 susceptible individuals. Except OPI-13520, all bands were confirmed as false positive. OPI-13520 band presumed as closely linked marker to white rust disease resistance was tested in whole population. Among 187 progenies, just six off-springs did not correspond with phenotypic data. Based on expected phenotypic segregation ratios in the pseudo F1 progenies, it was assumed that a duplex type of white rust resistance in ‘Dancer’ (RRrrrr) were in combination with a duplex type of OPI-13520 marker. As a result of x2-test of independence between resistance gene and OPI-13520 marker, x2 score is 76.08 and probability is 2.13x10-16. And resistance gene and OPI-13520 marker were assumed to be linked in coupling phase. The value of recombination fraction obtained by successive trials and second derivative of log likelihood was 0.03832±0.0271.

A single recessive gene, rxp, controls the bacterial leaf pustule (BLP) resistance in soybean and in our previous article, it has been mapped on linkage group (LG) D2 of molecular genetic map of soybean. A total of 130 recombinant inbred lines (RILs) from a cross between BLP-resistant SS2-2 and BLP-susceptible Jangyeobkong were used to identify molecular markers linked to rxp. Fifteen simple sequence repeat (SSR) markers on LG D2 were screened to construct a genetic map of rxp locus. Only four SSR markers, Satt135, Satt372, Satt448, and Satt486, showed parental polymorphisms. Using these markers, genetic scaffold map was constructed covering 26.2cM. Based on the single analysis of variance, Satt372 among these four SSR markers was the most significantly associated with the resistance to BLP. To develop new amplified fragment length polymorphism (AFLP) marker linked to the resistance gene, bulked segregant analysis (BSA) was employed. Resistance and susceptible bulks were made by pooling equal amount of genomic DNAs from ten of each in the segregating population. A total of 192 primer combinations were used to identify specific bands to the resistance, selecting three putative AFLP markers. These AFLP markers produced the fragment present in SS2-2 and the resistant bulk, and not in Jangyeobkong and the susceptible bulk. Linkage analysis revealed that McctEact97 (P=0.0004,~;R2=14.67~%) was more significant than Satt372, previously reported as the most closely linked marker.