Marker Assisted Selection in Advanced Backcross Population of Rice Variety, MTU1010 for Bacterial Blight and Blast Resistance

The present study was aimed for identification of the bacterial blight and blast resistant lines in the advanced back cross population of MTU-1010 using marker assisted foreground selection and also for evaluation of agro-morphological characters. The M-16-59 introgressed line (derived from an intercrossing of BC2F1 plants of MTU-1010 x GPP2 and MTU-1010 x NLR 145) is developed under ongoing DBTDBSRR subproject -IV possessing Xa21, xa13, Pi1 and Pi54 resistance genes having broad spectrum resistance to bacterial blight and blast is used as a donor parent and MTU-1010 was used as a recurrent parent for the back cross. Before attempting the backcross both the parents were verified for the target genes along with the original donors GPP2 and NLR 145 using gene specific/linked molecular markers viz., xa13-promo for xa13 gene, pTA248 for Xa21 gene, RM 224 for Pi1 and Pi54 MAS for Pi54. under the F1 generation (equivalent to BC3F1 because two backcrosses were completed earlier), 120 plants were screened, and 16 plants were confirmed for xa13, Xa21, Pi1, and Pi54 genes under heterozygous conditions. These confirmed plants were assessed for agro-morphological characteristics such as yield, grain features, and plant type. The results showed that the confirmed heterozygous plants were comparable to MTU-1010 and passed to the next round of selection and evaluation. The BC1F1-198th plant (96.8%) was selfed to produce BC1F2 population. Twenty five plants were advanced to BC1F3 generation based on BB resistance and above other phenotypic characters. The selected BC1F3 progenies were screened for blast and BB resistance. Four BC1F3 progenies with four target genes (xa13xa13Xa21Xa21Pi54Pi54Pi1Pi1) showed very high level of resistance to both the diseases. BC1F2-198-52nd line found similar to MTU1010 with respect to yield and yield related characters besides showing resistance to both BB and blast.Improved lines of MTU1010 can be advanced for multi-location testing under All India Coordinated Rice Improvement Project (AICRIP) for their evaluation and possible release for the benefit of rice farmers.