Sterility of intersubspecific hybrids of Oryza sativa L. in connection with search of genes of wide compatibility and correct reference of samples to subspecies Indica and Japonica

In rice ( Oryza sativa L.) between indica and japonica subspecies a number of transitional forms both on phenotype and on physiological determinants present, which have the characteristic features in their development and adaptation to stress. The heterosis effect in intersubspecific hybrids ( japonica/indica ) can be of 100 % and more. The superhigh heterosis can be used during intersubspecific hybridization on conditions that the genes of wide compatibility (WC), which ensure a grain content more of 70 %, will be involve in breeding. The authors made the crossings between the samples of domestic and foreign breeding from japonica subspecies. The analysis of grain formation in the hybrid combinations did not allow to reveal WC genes in studied varieties of Russian selection defining high fertility of hybrids. The molecular scanning of hybrids and their parental forms was made with the use of 11 polymorphous SSR-markers, typical for subspecies. A possibility to obtain the fertile intersubspecific hybrids of rice and the list of trait used for differentiating samples to subspecies japonica and indica are discussed. The obtained results show that it is necessary to include additional characteristics into the list of trait for the taxonomic attributing samples to indica and japonica subspecies.