Invastigations on effects of cold stratification, floating in ash sollution and sulfuric acid pretreatments on overcoming seed dormancy of crataegus orientalis (Paal. ex. m. bieb) (Oriental hawthorn) and Crataegus pontica (k. koch.) (Eastern Blacksea hawthorn) seeds

In this study, it was aimed to determine the preliminary treatments that could be effective for eliminating germination barriers in Crataegus orientalis (Oriental Hawthorn) and Crataegus pontica (Eastern Black Sea Hawthorn) seeds. For this purpose, chemical scarification of sulfuric acid (H2SO4 (98%)), floating in ash solution (Oak, 5%), hot-cold stratification and combinations of these pretreatments were applied for different durations. Seeds subjected to 86 pretreatments for each species were planted in April, 2016, according to the design of 4 replicated randomized block design in open field conditions. Although germination started in the 2016 vegetation period, it was not possible to obtain effective germination. The germinations obtained in 2017 were evaluated. As a result of the study, it was determined that in both species seeds pretreated together with cold stratification and ash solution could be obtained higher germination percentages compared to seeds pretreated together with sulfuric acid and cold stratification. The study also concluded that the germination barrier levels were higher in Crataegus orientalis seeds, based on the higher germination rate of Crataegus pontica seeds.