Validation of microsatellite molecular markers linked with resistance to Bipolaris sorokiniana in wheat (Triticum aestivum L.)

Abstract

SUMMARYSpot blotch disease caused by Bipolaris sorokiniana (Sacc.) Shoem causes yield losses and reduces grain quality in wheat. Molecular markers reported to be linked with resistance to B. sorokiniana could accelerate the identification of resistant genotypes as they are independent of the environmental effect. However, before they can be utilized for marker assisted selection (MAS), validation in an independent population is required. The objective of the present study was therefore to validate three simple sequence repeat (SSR) molecular markers (Xwgm570, Xgwm544 and Xgwm437) linked with resistance to B. sorokiniana. The markers were validated using 66 wheat genotypes comprising 11 parental genotypes and 55 F2 progenies. Single marker analysis was performed using simple linear regression to ascertain the relationship between the marker and the trait. All the markers were confirmed to be associated with resistance. They all gave significant association with resistance to B. sorokiniana. The markers amplified DNA fragments in the resistant parental genotypes that were similar to those observed in resistant F2 progenies, but absent in the susceptible ones. Hence, these markers could be useful in increasing the efficiency of selection for resistance to B. sorokiniana in wheat breeding. Since the R2 values are low, a combination of two or three SSR markers can be employed during MAS. This was evident by the multiple linear equation which gave a combined R2 value of 18·0%, obtained from the inclusion of all three markers.