Production of potato virus-free plants via meristem culture
2000
Majidi, Eslam | Davoodi, Daryoush | Hashem Poor, | Irandoost
Potato seed tubers produced by conventional methods are of many diseases and these contaminations are capable of passing viral diseases from one vegetative generation to the next. Pathogen attack does not always lead to death of plant. Many viruses may not even show visible symptoms. However, the presence of viruses in the plants can reduce the yield and/or quality of the crop. The virus cleaning and subsequent multiplication program begins with the selection of tubers from individual plants (clones). Before attempting virus eradication, the health status of the source plant should be determined in order to reduce the number of tests that must be applied to each of the plantlets that develop in culture. In vitro potato stock plants (Solanum tuberosum L. CV. Agria) were obtained from apical meristems followed by thermotherapy. These in vitro plants were multiplied by serial subcultures in 300 ml jars containing MS liquid medium. Cultures were incubated under 24/22℃day/night temperature regime with a 16-h photoperiod fluorescent light at an irradiance of 3000 lux (36 μmol m-2 s-1). Multiplication medium consisted of MS salts and vitamins, 30 gL-1 sucrose, 2 mgL-1 6-benzylaminopurine (BAP), 0.1 mgL-1 naphthalene acetic acid (NAA) and 1.0 mgL-1 gibberellic acid (GA3). Tuber induction medium was the same as basal medium except 80 g L-1 sucrose, and 7 mg L-1 BAP were used. Shoots produced in a 300ml jar were transplanted into a 3L bioreactor vessel and the medium was pumped into it every 8 hrs. to immerse the shoots for about 30 minutes. The entire medium was changed with tuber induction liquid medium after 4 weeks. These cultures were incubated under continuous dark condition at 20℃for 4 weeks. The growing shoots were subcultured from 300ml jar to bioreactor in which they continue to grow. After 3 days tuber induction was observed. The tuberization occurred mainly at middle part of the bioreactor. The total number of microtubers in this 3L bioreactor was about 550 and was very more efficient than routine system (3 to 4 microtubers per 300 ml jar).
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