Protocol: Rye A Agar ( For long-term maintenance) for 1 liter
- Soak 60 g of rye grain in distilled water for 24 hours at room temperature. This is done in a small tray so that water just covers grain. Cover tray tightly with aluminum foil.
- Next day, pour supernatant off germinated grain and put aside.
- Place grain in a beaker, add distilled water ( about 1 inch above grain) and blenderize on high for 2 minutes. Cook in water bath for 1 hour at 68C. Don’t modify extraction time or temperature.
- Filter through 4 thicknesses of cheese cloth squeezing gently to remove residual liquid. Discard cheese cloth and grain sediment.
- Combine original supernatant ( liq. poured off grain at the beginning) with filtrate. (At this point the preparation can be frozen for use later).
- Add 20g sucrose, 15g Bacto Agar then adjust volume to 1 liter.
- Autoclave at 15 psi for 20 minutes.
- One liter will yield 40-50, 100x15 mm petri plates.
Reference: Caten, C. E. and J. L. Jinks. 1968. Spontaneous variability of single isolates of Phytophthora infestans. I. Cultural variation. Can. J. Bot. 46: 329-348.
