8. Aeroponic technique in seed potato production
The technique of aeroponic culture is an optional method of
soil-less culture in growth-controlled environments such as greenhouses.
This method consists of enclosing root system in a dark
chamber and supplying nutrient solution with a mist device. The
aeroponic system mainly consists of an electrical unit, two light
proof (dark) growth chambers, a nutrient solution chamber, a high
pressure pump, filters, and spray nozzles as shown in Fig. 1 (Singh
et al., 2010).
In vitro grown 15–21 days old duly hardened microplants of
about 15 cm height are planted in the holes made in the roof of
the growth boxes of the aeroponic unit. All the essential nutrient
elements required for plant growth are dissolved in the water in the
nutrient tank (solution chamber), and solution pH is maintained at
the desired level throughout the crop period. The nutrient solution
is replenished from time to time (Otazu, 2010).
This nutrient solution is compressed through nozzles by a highpressure
pump, forming a fine mist in the growth chambers. At
the roof of the growth chambers, in vitro propagated and hardened
plantlets are planted in 20 mm diameter holes. Pump is automatically
operated for 10–30 s after every 10–30 min interval regulated
by an electronic timer and a conductor. This system maintains
growth chambers at 100% relative humidity by misting nutrient
solution round the clock. After a week, root system starts developing
inside the growth chambers. Like in the soil system, stolon
and tuber formations are initiated at different intervals depending
upon the variety. Picking of the tubers starts after 60–65 days
when some of the tubers attained 15–17 mm dia under other conventional
minituber production systems. Once the first flush is
harvested, formation of additional tubers is triggered resulting into
more minitubers/plant. is done after every two weeks, and in the
total 4 flushes is taken. On an average 30–35 minitubers can be
harvested from a single plant as against 8–10 minitubers under the
net-house. These minitubers are stored at 2–4 ◦C and are used for
planting in the next generation