Marker-assisted gene pyramiding (MAGP) for semi dwarfed bacterial blight resistance genes into traditional basmati variety “Ranbir Basmati”

Evolution of new virulent races has led to increased sensitiveness of the traditional basmati varieties to bacterial blight (BB) disease. Among the traditional basmati varieties, Ranbir Basmati is tall statured variety, and are susceptible to BB diseases. The variety has thin stem and prone to lodging leading to significant yield losses as well as deteriorate the grain qualities. In the present study, the marker-assisted backcross breeding (MABB) strategy were used for simultaneous stepwise transfer of two major BB resistance genes (Xa21 and xa13) along with a dwarfing gene (sd1) into Ranbir Basmati. The molecular markers viz., pTA 248, xa13prom and h linked to Xa21, xa13 and sd1, respectively were used in MABB programme. Both foreground and background selection approaches are used for pyramiding of genes of interest into Ranbir Basmati. The crosses were attempted for pyramiding the BB resistance genes along with dwarfing gene from Punjab Basmati 4 (Xa21, xa13 and sd1) into Ranbir Basmati. MABB programme was carried out up to BC2F5 generations. In total five semi-dwarf pyramided lines namely, SBTIL25, SBTIL39, SBTIL80, SBTIL121 and SBTIL31 have been identified for further field screening. These pyramided lines possess superior length/width ratio, excellent cooking properties and pleasant aroma. These five lines have been further evaluated for morpho-physiological and quality traits, and can be serve as potential donors for different rice pre-breeding programmes. These promising pyramided lines in bulk will be subjected to testing in multi-location and replicated trial for yield and disease resistance for their possible release as variety.