UNRAVELING THE GENETICS OF SUBMERGENCE TOLERANCE THROUGH PHENOTYPING AND MOLECULAR MARKER SCORING IN RICE (ORYZA SATIVA L.)

Abstract

The major rice quantitative trait locus Submergence 1 (Sub 1) confers tolerance to submergence for about 2 weeks. To identify the inheritance pattern of submergence tolerance, we have conducted a polymorphic survey using allele-specific markers targeting SUB1A and SUB1C and also field evaluation for assessing the tolerance mechanism through backcross populations developed with highly susceptible genotypes ADT43, Improved White Ponni (IWP) and highly tolerant genotype FR13A. The six generations viz., P1, P2, F1, F2, BC1 and BC2 of the two cross combinations viz., ADT 43 x FR 13A and IWP x FR 13A were used for this investigation. The marker segregation pattern indicated that a duplicate dominant allele influence tolerance as seen from the observed F2 ratio 15:1 for susceptible and tolerant in cross 1 and cross 2 under submergence condition. The study on inheritance pattern for submergence tolerance indicated that both the crosses the submergence tolerance was found to be controlled by duplicate dominant genes in which is confirmed through respective BC1 and BC2 crosses. The field study (phenotypic scoring) also confirmed the ratio in F2 of 15: 1 (duplicate dominant epistasis).