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

Quinoa is a dryland crop that is rich in nutrients and prefers cold. The emergence rate is one of the main factors affecting yield. Temperature and water availability are necessary conditions that affect seed germination and growth. Therefore, it is important to study quinoa’s emergence, field growth, and development under temperature and drought stress to achieve high-yield and high-efficiency quinoa cultivation. This study used the typical quinoa variety ‘Jili 3’ in the Bashang area as the experimental material. ①Seed germination test: three drought stress treatments (osmotic potential of PEG-6000 solution was 0, −0.3 MPa, and −0.6 MPa, respectively) and four temperatures (10℃/0℃, 15℃/5℃, 20℃/10℃, and 25℃/15℃). The effects of drought and temperature stress and their interactions on the germination rate, germination potential, root length, 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 the cold area of Bashang, Hebei Province. The results of the seed germination test showed that the germination rate, germination potential, root length, and bud length increased gradually with the increase in temperature, and the seed germination rate was higher at 20℃/10℃ and 25℃/15℃. The seed germination index decreased under drought-stress conditions. When the drought stress was light (PEG-6000 was −0.3 MPa), the activities of SOD and CAT were higher; and seed germination was less affected. The results of the field experiment showed that with a delay in the sowing date, the temperature and grain yield of quinoa during seedling emergence first decreased, then increased, and then decreased, with the highest treatment on June 1. Correlation analysis showed that the emergence rate was positively correlated with ambient temperature, and 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 on 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 areas of Bashang, it is not advisable to sow too early to ensure that the emergence rate of quinoa is not negatively affected by low temperatures. The most suitable sowing date was from mid-May to early June to ensure a suitable temperature for the growth of quinoa. The results provide a scientific basis for optimizing the management of quinoa planting in the cold areas of Bashang.