The Effect of Different Stratification and Scarification Treatments on Breaking the Dormancy of Saskatoon Berry Seeds

Abstract

Saskatoon berry has become as important as a commercial fruit crop. One main goal is to release new plant cultivars well adapted to different climatic and soil conditions. Dormant seeds obtained from breeding are serious problems delaying the program. The seeds were directly extracted from fruits after harvest (unstored) or after storage at −18 °C for 6 months (stored) and subjected to modified stratification (3 °C) with KNO3, H2O2, NO, smoke-water (SW) or scarification using sandpaper or H2SO4 for 10, 20, 30, 40 min or treatments with pulsed radio frequency (PRF) or red light. The seeds were also subjected to warm–cool stratification (20/3 °C). Unstored seeds germinated in a higher percentage and with better uniformity (T75–T25) than stored seeds. Stored seeds positively affected the onset of seed germination (T1) and mean germination time (MGT). Dormancy breakage was promoted by stratification with KNO3, SW or scarification with sandpaper, H2SO4 or treatments with PRF. The recommended method for the breeding program of breaking seeds dormancy is when unstored seeds are subjected to stratification in KNO3 (0.2%) or SW (1:100). Depending on the applied methods, the percentage of seeds’ germination increased to 87% compared to untreated (64%) control seeds. The positive effects of the selected methods persisted during seedling development by stimulating their growth and enhancing the chlorophyll content index (SPAD) and effective quantum yield of PSII of chlorophyll in leaves (ΦPSII).