03202naa a2200241 a 450000100080000000500110000800800410001910000210006024501230008126000090020430000120021349000370022550001800026252021480044270000190259070000190260970000160262870000170264470000190266170000190268070000150269977302460271414668482007-07-27       2004    bl uuuu     u00u1 u    #d1 aSÁ, M. E. L. de  aMicrosatellite markers linked to soybean cyst nematode resistance, race e, in a cross between two Brazilian cultivars.  c2004  ap. 319.  a(Embrapa Soja. Documentos, 228).  aEditado por Flávio Moscardi, Clara Beatriz Hoffmann-Campo, Odilon Ferreira Saraiva, Paulo Roberto Galerani, Francisco Carlos Krzyzanowski, Mercedes Concordia Carrão-Panizzi.  aThe identification of QTLs associated with SCN resistance would be useful in breeding programs using marker-assisted selection, speeding up the selection and eliminating the environmental effect. Microsatellites markers (SSR) have been presented as a powerful tool due to their efficiency, automation capability and low cost. The objective of this work was to identify SSR markers associated with QTLs for resistance to SCN, race 3. The study was based on 88 F2:3 families derived from a cross of two Brazilian soybean cultivars: BRSMG Segurança (susceptible) x BRSMG Liderança (resistant). SCN bioassays were performed under greenhouse conditions and the plantlets were inoculated with 4000 eggs. The Female Index (FI) was used to evaluate the SCN reaction. Twenty-two polymorphic microsatellite markers (in a total of 313 markers) were used to construct the linkage map employing MAPMAKER software, using a minimum LOD score of 2.5 and a maximum distance of 50cM. The Cartographer program was used to detect markers linked to QTLs. After that the SAS GLM procedure was employed to analyze the association between four detected markers and the putative resistance loci by Single Mark Analysis. Two microsatellite markers, Satt309 (P&lt0.0001; R2=29.5%) and Sat163 (P&lt0.0001, R2=24.3%), were strongly linked to one QTL conferring SCN resistance. This locus is located in the molecular linkage group (MLG) G. Other two markers, Satt241 (P=0.0011; R2=16.3%) and Satt573 (P=0.0006; R2=16.7%), also revealed association with another SCN resistance locus, although they were reported as belonging to different MLGs. In both loci the resistance alleles were originated from the resistant parent. In the MLG G the SCN resistance alleles, race 3, were dominant, while in the other MLG they were recessive. A two-way ANOVA for the closer markers to both QTLs (Satt309 and Satt241) accounted for about 43% of the phenotypic variation in the SCN resistance, and showed only additive effect. The selection efficiency, using a FI cutoff equal to 10%, only for homozygous families, varied from 42.9% to 65.0% when compared with the phenotypic selection.1 aBOTHONA, C. A.1 aBERNARDELI, K.1 aMORO, G. L.1 aSILVA, H. D.1 aARANTES, N. E.1 aGOULART, L. R.1 aFRONZA, V.  tIn: WORLD SOYBEAN RESEARCH CONFERENCE, 7.; INTERNATIONAL SOYBEAN PROCESSING AND UTILIZATION CONFERENCE, 4.; CONGRESSO BRASILEIRO DE SOJA, 3., 2004, Foz do Iguassu. Abstracts of contributed papers and posters. Londrina: Embrapa Soybean, 2004.