Study On Mapping And Fine Mapping Genes For Interspecific Hybrid Sterility Between Oryza Sativa L. And Oryza Longistaminata A. Chev.et Roehr.

Oryza sativa L. is an important crop, but the narrow genetic variation limits its improvement furture. Its wild relative, O. longistaminata A. Chev. et Roehr., which is rich in the genetic variation and has AA genome same as O. sativa is a valuable gene pool to achieve the sustainable development of rice production. However, hybrid sterility between them impairs the exploitation of favorable genes within O. longistaminata. So mapping hybrid sterile genes and clarifying the molecular mechanisms of hybrid sterility would help to improve O. sativa using O. longistaminata.To understand the genetic architecture of hybrid sterility, a series of near-isogenic lines (BC6F10) were developed via successive backcrosses, phynotype selection and marker-assisted selection using O. sativa (RD23) as recurrent parent and O. longistaminata as donor. In this study, BC7F2 populations for 10 NILs were raised and their pollen fertility and spikelet fertility were investigated. Genetic analysis, molecular mapping and fine mapping were done.The main results of this study are as follow:1.732 SSR markers were used to detect introgressive segments from O. longistaminata in the near-isogenic lines.2. Hybrid sterile genes were mapped in BC7F2 populations. A gamete eliminator,S1, was mapped near RM587 on the sixth chromosome; a pollen killer, S44(t), was mapped between RM5814 and RM20695 on the sixth chromosome and a pollen sterilie locus, qHSll, was mapped between RM332 to RM1124 on the eleventh chromosome. S44(t) and qHSll appear distinct from all previous reported loci.3. SI and S44(t) obeyed one-locus allelic sporophyte-gamete interaction mode. An epistatic interaction was detected between S44(t) and qHSll.4.2106 individuals were used to fine map S44(t), and it was limited in about 97.7kb region between RM20689 to RM20695 and 14 open reading frames were found.These results will lay a solid theoretical foundation for elucidating the nature of interspecific hybrid sterility and utilizing favorable genes from related species of O. sativa to guild rice breeding.