Microsatellite Markers Associated with Spot Blotch Resistance in Spring Wheat

Spot blotch, caused by Cochliobolus sativus, is a serious wheat (Triticum aestivum L.) disease in the warm areas of South Asia. Breeding for resistance in the past 15 years has produced limited progress, and newly developed wheat cultivars suffer considerable yield reductions under spot blotch epidemics in the region. Resistance is often controlled by multiple genes with additive effects. Marker-assisted selection, in combination with field selection, could accelerate the identification of progeny with multiple genes for resistance early in the breeding process. A study was conducted to determine microsatellite markers associated with resistance in the F7 progeny from a cross between the spot blotch-susceptible Sonalika and resistant G162 wheat genotypes. A parental survey using 171 simple sequence repeats (SSR) primer sets and spread over 21 chromosomes of wheat identified 52% polymorphic loci. However, only 15 polymorphic markers showed association with two bulks, one each of progeny with low and with high spot blotch severity. The detailed analysis indicated that progeny lines with low spot blotch severity could be separated from those with high severity using three SSR markers located on three wheat chromosomes. The findings may be useful in developing a marker-assisted selection strategy for spot blotch resistance in wheat.