SPINDIGO partners
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SPINDIGO Partners have grown indigo-yielding crops in Spain, Italy, Germany, UK and Finland for the past three years. The crops have been woad (Isatis tinctoria), Chinese woad (Isatis indigotica), and polygonum (Polygonum tinctorium). Using the key yield parameters of leaf weight and indigo yield per unit leaf weight, we have compared genetic lines from a variety of sources; analysed the relationship between indigo yield and the main environmental parameters of air temperature, global radiation, day-length, rainfall, and photosynthetically active radiation (PAR). We find that woad grows well in all the climatic zones examined, with yields of indigo up to 100 kg indigo/ha; Chinese woad gives higher yields, but is less reliable because of bolting and disease susceptibility; while polygonum yields well, and is more suited to Central Europe and the Mediterranean, but tolerates neither drought nor very high temperatures.
