Dormancy Spreads Seed Germination over a Long Period with a Discontinuous Procession in Aegilops tauschii , the D-genome Donor Species of Bread Wheat

摘要

Aegilops tauschii Coss. is the donor species of D-genome of bread wheat. This species has been widely utilized in wheat improvement. However, Ae. tauschii has been becoming the high-risk weed in the bread wheat fields of China. Dormancy is the vital factor for the weed reproduction during its life cycle. In the present study, we firstly observed the dormancy for a long time by monitoring the germination procession of three Ae. tauschii accessions under laboratory conditions for 120 days. The results revealed that all Ae. tauschii accessions had long and discontinuous dormancy. There were differences between intact spikelets and threshed seeds. Intact spikelets of all the three Ae. tauschii accessions displayed two obvious peaks of germination at about 50 and 90th day. However, time of peak appearance of threshed seeds was different among accessions. The dormancy characteristic of Ae. tauschii provides the possibility for this species as weed under a wide range of environments.