Heterotic response of genomic regions derived from Oryza rufipogon and O. nivara in improving grain morphology and quality of indica rice (Oryza sativa L.)

Limited backcrossing was followed to introgress useful variability, needed for improving grain morphology and milling traits, from wild Oryza species into two indica cultivars PR114 and Pusa44.These alien introgressions lines (ILs), having similar grain quality parameters to the recurrent parent, were used for developing rice hybrids to assess the effect of these introgressions in the heterozygous state and to assess their grain quality parameters, as most of the hybrids commercialized in the tropics have inferior grain quality. These ILs and their recurrent parents, possessing fertility restoration ability for wide abortive cytoplasm, were crossed with CMS line PMS 17A to generate introgressions line hybrids (ILHs). Hybrids developed from recurrent parents were used as a check to compare the performance of ILHs. Based on yield and phenotypic acceptability, six ILHs having enriched genome of O. rufipogon and O. nivara were selected and analyzed for grain quality traits. All six hybrids observed significant improvement in milled rice recovery (up to 10%), head rice recovery (up to 25%) over ILs and check hybrids. Introgressions were analyzed using polymorphic SSR markers. The majority of O. rufipogon and O.nivara alleles identified in the study seems to be effective across recipient genotypes and could be used effectively in quality breeding programs.