Effect of environmental, seed burial depth, and straw mulch on germination and seedling emergence in Cichorium glandulosum

Cichorium glandulosum Boiss. et Huet is a species that has recently spread widely in the autumn crops of northwestern Iran. A study was conducted to evaluate the effect of environmental factors on the germination, emergence, and management of two populations of C. glandulosum. The effects of temperature, photoperiod, NaCl concentration, osmotic potential, seed burial depth, and straw mulch on seed germination and seedling emergence were evaluated for two populations of C. glandulosum from Tabriz and Marand, Iran. The highest germination percentage was observed in the Tabriz (93%) and Marand populations (94%) at 20/10 C (day/night). In both populations, germination was 82% to 93% across a wide range of light/dark periods (8 to 24 h of light). However, germination was significantly reduced (similar to 70%) under continuous darkness. The osmotic potential required to inhibit 50% of germination was 0.68 MPa for the Tabriz population and 0.62 MPa for the Marand population. The concentration of NaCl required to inhibit 50% of germination was 4.76 dS m(-1) for the Tabriz population and 3.81 dS m(-1) for the Marand population. The seed burial depths that caused a 50% decrease in emergence for the Tabriz and Marand populations were 1.86 cm and 2.22 cm, respectively. In the Tabriz and Marand populations, the application of 6000 kg ha(-1) of straw mulch resulted in a decrease in C. glandulosum emergence to 3% and 10%, respectively. This study's results inform the conditions required for C. glandulosum germination and establish a theoretical and practical foundation for predicting, preventing, and managing this species using scientific principles.