EFFECT OF THERMOTHERAPY AND MERISTEM-TIP CULTURE ON PRODUCTION OF VIRUS-FREE GARLIC IN CHILE

Garlic cultivars for crop production in Chile are infected with onion yellow dwarf virus (OYDV), (Bruna et al., 1992). In order to produce virus-free garlic, thermotherapy and meristem-tip culture trials were carried out.
In a first trial, garlic cloves cultivar Rosado-INIA were preconditioned at 30°C for 7 days and then treated at 38°C for 38 days in environmental growth chambers.
The control cloves were incubated at 20°C for 45 days.
Meristem tips around 0,5 to 0,8 mm in diameter were excised and grown in medium containing macronutrients of B₅ (Gamborg et al., 1968) and the micronutrients and vitamins of M & S (Murashige et al., 1962). Three months later the plantlets were transplanted to greenhouse and indexed by ELISA. (Clark et al., 1977). 65% of garlic plants regenerated from explants were free from OYDV. When infected cloves were subjected to thermotherapy at 38°C before tissue culture, 100% of the plants were OYDV-free.

In a second trial, garlic cloves were subjected to thermotherapy at 38°C for different periods of time (48–54–60–67 and 75 days) and then indexed by ELISA. This was compared with garlic cloves precondioned at 30°C for 7 days before being exposed to 38° C for the same periods of time already described.

The percentage of virus-free garlic plants increased from 38 with 48 days at 38°C to 100% with 75 days at 38°C. The percentage of plants alive decreased from 95% on the 48 days treatment to 62% on the 75 day’s treatment.
Preconditioning was not necessary under our environmental conditions.

I International Symposium on Edible Alliaceae

A. Bruna

https://doi.org/10.17660/ActaHortic.1997.433.72