Understanding seed dormancy breakage and germination ecology of Cynara cardunculus (Asteraceae)

HUARTE ROBERTO; BOLANDELLI F; VARISCO D; BATLLA, DIEGO

WEED RESEARCH

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2018

0043-1737

Cynara cardunculus is a troublesome weed in temperate grazing lands of Argentina and many other countries. C. cardunculus achenes are usually dormant at dispersal and require alternating temperatures to terminate dormancy and germinate. Here, we present results of experiments carried out to explore treatments, other than alternating temperatures, able to terminates dormancy of C. cardunculus dormant achenes and determine the effect of different environmental factors and agronomic practices on non-dormant (dry afterripened) C. cardunculus achenes germination and emergence. Scarification, hydrogen peroxide and sodium hypochlorite promoted germination of C. cardunculus dormant achenes. Dry afterripening and cold stratification were tested in two different population. Dormancy of both populations were released by dry afterripening. In contrast, cold stratification allowed dormancy release in one population while the another one was induced into secondary dormancy. Germination of non-dormant (dry afterripened) achenes was maximum in a range of temperatures from 10 to 20°C and was inhibited at higher temperatures. Reduction of osmotic potential below -0.6 MPa. lead to a decrease in final germination. These results explain, at least partially, the adaptation of C. cardunculus to autumn emergence after dormancy release during summer. Maximum seedling emergence was close to 60% at soil depths of 1 cm and only decreased as depth increased over 6 cm, with no emergence at 8 cm. Seedling emergence was not reduced by the presence of cover residues and a flooding duration of 21 d was required to suppress emergence significantly. This information is useful to increase the understanding of C. cardunculus seed ecology and could facilitate the development of effective weed control programs.