OPTIMIZATION OF WEED SEED DORMANCY BY CHEMICAL AND PHYSICAL TREATMENTS

The dormancy of weeds plays a very important ecological role. It prevents the seeds from germinating, as soon, and to be destroyed by climatic conditions that are unfavorable to their growth. The dormancy is the result of a complex interaction between the genome and the agroclimatic factors that seed-bearing plants undergo during their "reproductive and vegetative phase". Knowledge of the time of emergence and the dynamics of weed seed germination and the factors that affect it gives us an idea of the infestation of agricultural areas by these weeds, This would reduce the use of herbicides without affecting crop yields or weed control levels. This article presents the results of seed germination tests and the emergence of dormancy of the following weeds: Phalaris brachystachys, Avena sterilis, Ridolfia segetum, Centaurea diluta, Cichorium endivia, Lolium rigidumn and Picris echioides , in which four methods were applied to seeds in order to promote germination , a chemical treatment with the phytohormone giberelic acid (GA3), mechanical scarification with a scalpel, cold stratification 4°C, and a cold stratification at 0°C . The results obtained showed that mechanical and chemical scarification recorded the highest germination percentages in our species with an average of 81.42% and 75.23% respectively, while stratification (0° and 4°) gave a low average of 62% and 67%. The results found confirm with others that mechanical scarification and chemical treatment with gibberellic acid increses the germination of the tested seeds to a greater extent. thus revealing a physical dormancy induced by their teguments. This will enable farmers to use stratification 0° and 4° to block seed weed germination.