Genetic and Physiological Improvement of Rice forSubmergenceTolerance
Author:D. Vijayalakshmi1* and M. Raveendran2
Submergence stress is a major problem in Tamil Nadu during the monsoons. Every year paddy
production is greatly affected due to flash floods. A major QTL on chromosome 9, Sub1 has
provided the opportunity to apply Marker Assisted Backcrossing (MAB) to develop submergence
tolerant versions of rice cultivars that are widely grown in the region. Present study was at
aimed at marker assisted introgression of Sub1 locus controlling submergence tolerance from
FR 13A into the background of CO 43, a popularly grown rice variety in the cauvery delta region.
Molecular markers that were tightly linked with Sub1, flanking Sub1, and unlinked to Sub1 were
used for foreground, recombinant, and background selection, respectively, in backcrosses
between a submergence tolerant donor, FR 13A and the widely grown recurrent parent, CO 43.
Polymorphic markers for foreground and background selection were identified. Genotyping and
phenotyping of BC1
and F2 generations revealed the superiority of the plants introgressed with
Sub1 locus. By the BC2
generations a submergence tolerant plant was identified that
possessed 100% CO 43 genome with Sub1 locus. These backcross progenies were evaluated for
their tolerance against flooding. All the plants were able to survive 11 days of complete flooding.
Key Words: Rice, Submergence tolerance, Marker assisted breeding, Genotyping, Phenotyping