Effect of harvest time, drying technique, temperature and light on the germination of quinoa (Chenopodium quinoa)

The influence of light, temperature and dry matter content of seeds on germination in quinoa (Chenopodium quinoa Willd.) was investigated under laboratory conditions, using seed harvested at weekly intervals over seven weeks. Light had no influence either on the germination rate or final germination. The number of seeds which germinated was affected significantly by harvest time, moisture content of the seed at harvest and germination temperature. At higher temperatures seeds germinated rapidly regardless of harvest time and moisture content of the seed at harvest, so that at 20 degrees C average germination was 99%, while at 10 degrees C average germination was reduced to 85%. Lowering the temperature to 6 degrees C reduced average germination to 25%, but at this temperature an interaction with harvest date was recorded, so that delaying harvest increased final germination. No significant difference was detected between germination rate at 6 and 10 degrees C. Time to 50% germination was 2.1, 3.9 and 4.1 days, and maximum increase in germination per day was 11.1, 3.9 and 3.3% at 20, 10 and 6 degrees C, respectively. Drying seeds after harvest at 35 degrees C resulted in 2% higher germination than drying at 25 degrees C. It is recommended that quinoa is sown when the soil temperature is 8-10 degrees C. To obtain laboratory germination comparable to field germination, tests should be conducted at 6 or 10 degrees C as differences in seed quality, which are important in the field, are not revealed at 20 degrees C.