Abstract

Autotetraploid rice is a new germplasm developed through diploid chromosome doubling. Hybrids developed by indica autotetraploid rice crossed by japonica autotetraploid rice has clear biological advantage on F₁, causing widespread concerns for special research evolution to evaluate and utilize F₁ hybrid vigor. However, the widespread fertility of F₁ indica and japonica autotetraploid rice is low, which makes it difficult to direct utilization of F₁ vigor. In diploid indica and japonica rice, the fertility of F₁ hybrids is also proved to be low. Embryo sac infertility is known to be one of the most important reasons for hybrid sterility and many studies has indicated that the primary cause of F1 sterility was abortion of the embryo sac, which was identified by the genotype of the S5 gene on the chromosome. Previous studies have cloned S₅ based on common wild rice and cultivated rice and S₅ sequence was obtained and studied. In this paper, typical sequence of different materials of S₅ japonica and indica rice group of autotetraploid hybrids observed with whole-mount eosin B-staining confocal laser scanning microscopy WE-CLSM was utilized, to overcome F₁ hybrids embryo sac sterility.

Key words: rice (Oryza sativa L.); autotetraploid; hybrid sterility; S₅ gene; embryo sac fertility.