FAN, SHUGUO*, CHENGYE LIANG, AND HONGXIAN LIU. South China Institute of Botany, Academia Sinica, Guangzhou 510650, P. R. China. - Fertility-restoring mutants in somaclones of male-sterile rice (Oryza sativa L.) cultured in vitro.
Young panicles from three rice varieties, Zhenshan 97A (WA type
cytoplasmic male-sterile (CMS) line, indica), Hongyuan A (HL type CMS
line, indica) and Baoyuan A (BT type CMS line, indica), were cultured
on different media. Regenerated plants were obtained. Pollen fertility
was examined. Characteristic of fertility-restoring mutants was
examined. The main results were as follows: Two fertile revertants
were found in R1 regenerated plants of Zhenshan 97A with 100% fertile
pollens and more than 90% self seed set rate. One of the stabilized
fertile revertants (coded A3-9-15-2) was named R type restoration
which could restore the fertility of CMS lines, and its self seed set
rate was over 80% in F1 hybrids. Genetic analysis of the progenies of
the tested crosses indicated that the fertility restoration of
Zhenshan 97A involved two pairs of restoring genes. The other fertile
revertant was named B type restoration which could maintain the
sterility of CMS lines for five generations all along. These two
fertile revertants were similar to Zhenshan 97B in major agronomic
characters. Three fertile revertants were found in R1 regenerated
plants of Hongyuan A (coded HF-1, HF-2 and HF-3) and Baoyuan A (coded
BF-1, BF-2 and BF-3) respectively. One excellent restorer line was
obtained from the fertile revertants of Baoyuan A (coded BR-1) and
Hongyuan A (coded HR-1) by means of genealogical method respectively.
Development of fertility-restoring mutant by somaclonal variation
could be used as an effective method to obtain restorer line of CMS
line.
Key words: cytoplasmic male sterility (CMS), fertile revertant, in vitro culture, indica, japonica, Oryza sativa L.