Effects of water and temperature on seed germination and grain yield of quinoa

Quinoa is a kind of dry land crop which is rich in nutrients and likes cold. The emergence rate is one of the main factors affecting its yield. Temperature and water are the necessary conditions affecting seed germination and growth. Therefore, it is of great significance to study the emergence and field growth and development of quinoa under temperature and drought stress for high yield and high efficiency cultivation of quinoa. In this study, the typical quinoa variety 'Jili 3' in Bashang area was used as the experimental material. ①Seed germination test: three drought stress treatments (osmotic potential of PEG-6000 solution was 0, −0.3 MPa, −0.6 MPa, respectively) and four temperatures (10℃/0℃, 15℃/5℃, 20℃/10℃, 25℃/15℃). The effects of drought and temperature stress and their interaction on germination rate, germination potential, root length and shoot length, superoxide dismutase and catalase were analyzed, and the response mechanism to environmental stress factors was clarified. ②Sowing date test: five sowing dates of May 1, May 11, May 21, June 1 and June 11 were set up to explore the effects of different sowing dates on seedling emergence rate and yield, and to clarify the suitable planting time for high yield of quinoa in cold area of Bashang, Hebei. The results of seed germination test showed that the germination rate, germination potential, root length and bud length increased gradually with the increase of temperature, and the seed germination rate was higher at 20℃/10℃ and 25℃/15℃. Under drought stress, the seed germination index decreased as a whole. When the drought stress was light (PEG-6000 was −0.3 MPa), the activities of SOD and CAT were higher. and the seed germination was less affected. The results of field experiment showed that with the delay of sowing date, the temperature and grain yield of quinoa during seedling emergence decreased first, then increased and then decreased, with the highest treatment on June 1. Correlation analysis showed that the emergence rate was positively correlated with the ambient temperature, and the yield was significantly positively correlated with the number of plants. The average temperature during the emergence period of the sowing date on June 1 was 17.77℃, and the emergence rate was 95.72%. The average temperature during the emergence period of the sowing date on May 11 was 5.90℃, and the emergence rate was 6.58%. Compared with the sowing date of May 11, the yield of June 1 increased by 435.67 kg∙hm⁻². The above results showed that quinoa seeds could tolerate a certain degree of drought stress, but the germination performance was poor at temperatures below 15℃/5℃. In the cold area of Bashang, in order to ensure that the emergence rate of quinoa is not negatively affected by low temperature, it is not advisable to sow too early. The suitable sowing date is from mid-May to early June to ensure the suitable temperature required for the growth of quinoa. The results can provide a scientific basis for optimizing the management of quinoa planting in the cold area of Bashang.