Abstract

VALIDATION OF WHEAT MAPPING POPULATION FOR KARNAL BUNT DISEASE RESISTANCE USING MICROSATELLITE MARKERS: A MOLECULAR APPROACH

Sudhir Singh Chandel*, Rajani Nigam and Ram Naresh Saket

ABSTRACT

Tilletia indica, a fungus responsible for causing Karnal bunt (KB) disease in wheat, poses a significant challenge to the grain industry not due to substantial yield loss but because of quarantine regulations restricting the free movement of affected grain in international trade. Various sources of resistance to KB have been identified, and understanding the genetics of this resistance is crucial for incorporating it into new wheat cultivars. Furthermore, the identification of PCR-based markers linked to KB resistance opens the possibility of employing marker-assisted selection schemes in breeding resistant wheat cultivars. This study involved generating recombinant inbred line (RIL) populations from crosses of susceptible cultivars HD-2009 and WL-711 with resistant parents HD-29 and HD-30. The F4 and F5 populations were evaluated for resistance against the KB pathogen
under artificial epiphytotic conditions in a greenhouse. This research aims to leverage simple sequence repeat (SSR) primers to identify DNA markers closely linked to KB resistance genes in bread wheat. Four SSR primers (Xgwm88-6B, Xgwm337-1D, Xgwm637-4A, and Xgwm538-4B) specific for the KB resistance gene were used to screen wheat populations from a single cross, HD 30x HD 2009, and HD 29x WL711. Each primer revealed one to two resolvable bands. Notably, Xgwm88-6B, Xgwm637-4A, and Xgwm538-4B produced single bands of a specific base pair (bp), while Xgwm337-1D generated two alleles with amplicons of bp and bp. This study highlights the effectiveness of SSR technology and confirms the presence of the KB resistance gene in the newly developed RIL populations.

Keywords: Karnal bunt disease, Tilletiaindica, Recombinant inbred lines, SSR primers.