Development of SCAR marker linked to stem canker resistance gene in soybean

Abstract

Stem canker caused by the fungus Diaporthe phaseolorum f. sp. meridionalis is a disease that limits soybeancultivation. Phenotypic evaluations aiming at disease resistance require labor-intensive processes, as for instance handlingand transport of phytopathogens. The use of DNA markers in the selective procedures eases certain phases, besides beingpractical, safe and reliable. A RAPD fragment of 588pb was identified among bulks of resistant and susceptible plants in thecross BR92-15454 (R) x IAC-11 (S). Through co-segregation, the distance between the resistance locus and the fragment wasestimated at 7.4 ± 2.1 cM, with a Lodmax. of 23.072 (first year) and at 6.0 ± 3.4 cM with a Lodmax. of 7.806 (second year). Thefragment was converted into a SCAR marker and digested with enzyme Hinc II, which made the classification in homozygousresistant, heterozygous resistant and susceptible plants possible. This SCAR marker is suitable for use in the improvementprogram conducted in Jaboticabal.

Keywords

• RAPD
• Glycine max
• Diaporthe phaseolorum f. sp. meridionalis
• assisted selection