Studies on Effects of Different Temperature Treatments on Seed Germination and Vitality of Brassica juncea

Objective As an important vegetable, Brassica juncea has high economic value due to its edible and processed characters. However, the possible seed dormancy after harvesting is harmful to agricultural production, hence, studies on seed germination and vigor may contribute to understanding the physiological rules and timely sawing of B. juncea seeds.

Method In order to study the relationship between temperature and seed vigor and dormancy, B. juncea seeds harvested in 2017 and 2020 were used to analyze indexes of seed germination, seedling number, seedling length, mean germination time (MGT), and seedling vigor index (SVI) at 25℃ (CK), 4℃ and -10℃ with different treatment time.

Result Seeds harvested in 2017 (hereinafter called 2017 seeds) had no dormancy but seeds harvested in 2020 (hereinafter called 2020 seeds) did have instead. And vigor indexes of 2020 seeds were extremely higher than those of 2017 seeds. The germination rate of 2017 seeds was less than 20%, and SVI was less than 1.5, however, the germination rate of 2020 seeds was higher than 60%, and SVI was more than 5. Especially, the germination rate of 2020 seeds was increased to 80% under -10℃ treatment.

Conclusion Short time (24 h) treatment at 4℃ was adverse to seed germination of B. juncea seeds, but -10℃ treatment under dry condition was beneficial to breaking seed dormancy and raising seed vigor. Finally, seed storage time should be controlled in 1 year.