FAN, SHUGUO*, CHENGYE LIANG, AND HONGXIAN LIU. South China Institute of Botany, Academia Sinica, Guangzhou 510650, P. R. China. - Somaclonal male sterile mutants and their expressions in male sterile rice (Oryza sativa L.) somaclones.
Young panicles from five rice varieties, Zhenshan 97A (WA type
cytoplasmic male-sterile (CMS) line, indica), Hongyuan A (HL type CMS
line, indica), Baoyuan A (BT type CMS line, indica), Nongken 58s
(photoperiod-sensitive genic male-sterile rice (PGMR), japonica) and
W6154s (thermo-sensitive genic male-sterile rice (TGMR), indica), were
cultured on different media. 10 cases of male-sterile variants in
three rice varieties, Hongyuan A, Baoyuan A and W6154s were found.
Abortive pollen of rice could be classified into four types: pollen
free type (PFT), typical abortion type (TAT), spherical abortion type
(SpAT) and stained abortion type (StAT). The phenomenon that type of
pollen abortion could change from one to another through tissue
culture was found in rice somaclones in R1 generation. Male-sterile
variants in R1 generation were crossed with ten typical maintainer
lines and restorer lines (Zhenshan 97B, Erjiuai 4B, Hongyuan B,
Baoyuan B, Taiyin 1, Minghui 63, Ce 64, IR24, IR26 and IR36) to
investigate the restoring and maintaining relationship of these
male-sterile variants. The main results were as follows: The restoring
and maintaining relationship of one typical abortion type (TAT)
variant in R1 regenerated plants which derived from Baoyuan A (coded
28-18) was the same as that of WA type. The variant had been
backcrossed with their maintainer lines for five generations, and kept
sterile all along. Four male-sterile variants, which derived from
Hongyuan A (one was coded 24-1, StAT; the other was coded S14-1, TAT)
and Baoyuan A (one was coded 28-5, SpAT; the other was coded 28-19,
TAT), kept sterile continuously for five generations when they were
backcrossed with the ten parents stated above. The other five
male-sterile variants, which derived from Hongyuan A (coded 24-5),
Baoyuan A (coded 28-35) and W6154s (coded WP-1, WP-2 and WS) turned
into fertility with a lot of fertile pollens and more than 80% self
seed set rate when they were crossed with the ten parents stated
above.
Key words: in vitro culture, indica, japonica, male sterile mutants, Oryza sativa L., somaclone