Dissection of wheat spot blotch disease resistance QTLs in to single Mendelian genes

Two QTLs imparting spot blotch resistance and located on chromosomes 2BS and 5BL were dissected in to a single Mendelian gene using 341 single seed descent (SSD) derived F-3 and F-4 lines of YS102 x Sena lika and 335 F-3, F-4 and F-5 lines of YS116 x Sena lika cross. The resistant parental lines YS102 and YS116 were selected on the basis of phenotypic and genotyping data of base mapping population (Yangmai 6 x Sone lika in F-12 generation) used for QTL mapping. Both the populations were tested for spot blotch resistance under artificial epiphytotic conditions in the field. Disease severity (%) and AUDPC values of each line were calculated. The parent YS116 was known to possess a single major QTL on chromosome 5BL, while YS102 possess QTL on chromosome 2BS. The test for goodness of fit (1:2:1 in F-3, 3:2:3 in F-4 and 7:2:7 in F-5 generations) confirmed segregation at one locus in both the crosses. These SSD derived lines from both the crosses may further be used for fine mapping and map based cloning of the QTLs of spot blotch resistance OTLs.