Molecular breeding for charcoal rot resistance in soybean I. Screening and mapping population development

Charcoal rot caused by Macrophomina phaseolina is a major yield reducing disease in the soybean growing countries across the world. Its effect is more pronounced in crops under stress, biotic or abiotic. Changing global climatic conditions particularly occurrence of frequent drought or drought-like situations are making soybean more vulnerable to this disease. Improper screening methods rendered conventional breeding approaches unproductive. Identification of molecular marker(s) linked to the charcoal rot resistance gene would greatly facilitate screening and thus accelerate the development of new cultivars. A core set of 100 diverse genotypes were subjected to screening for resistance under paper towel methods. No genotypes were immune; 7 germplasm lines appeared to be resistant. F₁ hybrids were produced by crossing resistant and highly susceptible genotypes. Parental polymorphism and purity of the F₁ hybrids was established using SSR markers. Advancement has been made to develop mapping population to map QTL for charcoal rot resistance in soybean.