*5.2.1 Exploitation of inter-specific heterosis*

Inter-subspecific (*indica/japonica*) hybrids as discussed in earlier section are more heterotic than intra-subspecific hybrids. However, owing to hybrid sterility and poor grain quality, this genetic pool remains untapped. Grain quality of inter-subspecific hybrids proposed to be improved by utilizing parental combinations having good combining ability but similar in quality parameters, might reduce the concern of segregation for quality traits. Hybrid sterility problem in inter-subspecific hybrids can be addressed by stacking *indica* allele (*S-i*) at *Sb, Sc, Sd,* and *Se* loci and the neutral allele (*S-n*) at *S5*locusin to *japonica* genetic background [35] or by silencing the *S-i* and *S5* mutant loci through genome editing tools [34].
