Cytohistological studies on male sterility in different cytoplasmic genetic male sterile lines of rice (Oryza sativa L.).

摘要

Cytological, cytohistological and morphological causes for pollen breakdown in two cytoplasmic genetic male sterile lines, MS577A and IR58025A, were carried out in comparison with their corresponding maintainer lines (MS577B and IR58025B) and a restorer line (Vajram). The anther sac layers, i.e. the inner tapetum, middle endothecium and outer epidermis showed slight variation in their thickness at all stages among the lines but showed normal behaviour in development in all studied genotypes. In IR58025A, the critical stage of breakdown was at the binucleate stage, whereas in MS577A pollen grains were morphologically similar to its maintainer line but failed to fertilize on selfing. The reason for pollen breakdown may be incompatibility between nuclear and cytoplasm genes.