Abstract:
Spot 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.
