Seed characteristics of Bromus catharticus at different harvest times

The study was to clarify the changes in seed moisture content, thousand-seed weight, seed germination, and conductivity of Bromus catharticus at different harvest times (8, 13, 19, 25, 32, 36, and 42 d after the onset of the flowering period). Jiangxia and Qiannan varieties were studied as test materials. The results showed that the seed moisture content of the two varieties decreased gradually with seed maturation; however, the change in thousand-seed weight showed the opposite trend and tended to stabilize at 32 d after flowering in the Wuhan area. Germination rate, germination potential, germination index, and vigor index of the seeds harvested at different stages showed a gradual increasing trend, except on day 42 after flowering, when the values decreased slightly. However, no significant differences were observed for any index from 32 to 42 d after flowering (P > 0.05). During the seed maturation process, the conductivity of the two varieties decreased continuously from 379.45 μs·(cm·g)^–1 and from 340.90 μs·(cm·g)^–1, respectively, at day 8 after early flowering to more than 84% by day 42. The differences were significant at 8 – 42 d (P < 0.05). Taking this into consideration, the best harvest time for B. catharticus was between days 32 and 36 after flowering, and the seed water content of Jiangxia and Qiannan was 26%～45% and 32%～49%, respectively.