Abstract:
In-vitro responses of fresh and old calli of japonica variety, Taipei 309, and indica
variety, Qiuguiai 11, were investigated with different culture procedures to develop
an efficient protocol to improve the regeneration efficiency of long-term cultured calli
of rice. Pre-culture media were used to restore the declined plant regeneration
ability in long-term cultured calli. Both proliferation rates and regeneration
efficiencies were compared between 2 varieties with fresh and old calli before and
after using pre-culture media. It was clear that in-vitro culture responses were being
declined after the second subculture of calli, indicating the loss of abilities to
regenerate plants from long-term cultured calli in rice. An efficient protocol
developed in this study with a pre-culture medium containing 10 mg/l BA,4 mg/l ABA,
1 mg/l NAA and 3% maltose showed 7-9 folds increase of in-vitro responses in longterm cultured old calli. This protocol not only restored the declined in-vitro ability,
but also reduced the somaclonal variation, especially in indica variety, Qiuguiai 11.
Furthermore, japonica variety, Taipei 309, performed well in the proliferation
cultures before and after using pre-culture media, showing higher proliferation rates
with both fresh and old calli, comparing with indica variety, Qiuguiai 11. Higher
regeneration efficiencies with less number of albino plants were given by indica
variety, Qiuguiai 11 throughout the study. This study clearly indicates that the invitro culture responses in rice depend mainly on the varieties of different subspecies,
culture conditions and compositions, and the stages of the culture procedures.
