Wj. Tao et al., ESTABLISHING JAPONICA RICE SUSPENSIONS RETAINING A HIGH REGENERATION POTENTIAL AFTER 14 MONTHS OF CULTURE, Plant cell, tissue and organ culture, 47(3), 1996, pp. 213-216
We report here a method of 'two cycles of selection' for rapidly estab
lishing rice embryogenic cell suspensions which had high regeneration
potential even after long-term culture (up to 14 months). Embryogenic
calli were induced from immature embryos of 17 genotypes of cultivated
japonica rice (Oryza sativa L.) and tested for their regeneration pot
ential. Five of the 17 genotypes showed relatively high regeneration f
requencies (27%-45%) and were selected. This process was the first cyc
le selection, namely, the selection for responding genotypes. The seco
nd cycle of selection, or the selection for responding individual call
us, was then conducted. Calli from different immature embryos of the s
ame genotype were found to differ in regeneration potential, therefore
calli with high regeneration potential were selected again in each of
the five genotypes. Five finely-dispersed and rapidly-growing embryog
enic cell suspensions, one for each of the genotypes, were established
from the calli chosen by the two cycles of selection. The regeneratio
n potential of these cell suspensions-was tested every two months over
a period of 14 months. All of the five genotypes retained high regene
ration frequency (above 62%) over the whole period tested.