Citation: Górnik, K.; Sas-Paszt, L.; Seliga, L.; Pluta, S.; Derkowska, E.; Gluszek, S.; Sumorok, B.; Mosa, W.F.A. The Effect of Different Stratification and Scarification Treatments on Breaking the Dormancy of Saskatoon Berry Seeds. Agronomy 2023, 13, 520. https:// doi.org/10.3390/agronomy13020520 Academic Editor: Frederic Marsolais Received: 16 January 2023 Revised: 4 February 2023 Accepted: 8 February 2023 Published: 11 February 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). agronomy Article The Effect of Different Stratification and Scarification Treatments on Breaking the Dormancy of Saskatoon Berry Seeds Krzysztof Górnik 1, * , Lidia Sas-Paszt 1 , Lukasz Seliga 2 , Stanislaw Pluta 2 , Edyta Derkowska 1 , Slawomir Gluszek 1 , Beata Sumorok 1 and Walid F. A. Mosa 3 1 Department of Microbiology and Rhizosphere, The National Institute of Horticultural Research, Konstytucji 3 Maja 1/3, 96-100 Skierniewice, Poland 2 Department of Horticultural Crop Breeding, The National Institute of Horticultural Research, Konstytucji 3 Maja 1/3, 96-100 Skierniewice, Poland 3 Plant Production Department, Faculty of Agriculture, Saba Basha, Alexandria University, Alexandria 21531, Egypt * Correspondence: krzysztof.gornik@inhort.pl; Tel.: +48-46-8345504 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 KNO 3 ,H 2 O 2 , NO, smoke-water (SW) or scarification using sandpaper or H 2 SO 4 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 (T 75 –T 25 ) than stored seeds. Stored seeds positively affected the onset of seed germination (T 1 ) and mean germination time (MGT). Dormancy breakage was promoted by stratification with KNO 3 , SW or scarification with sandpaper, H 2 SO 4 or treatments with PRF. The recommended method for the breeding program of breaking seeds dormancy is when unstored seeds are subjected to stratification in KNO 3 (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). Keywords: Saskatoon berry; Amelanchier alnifolia Nutt.; seed dormancy breaking; seed stratification; seed scarification 1. Introduction The genus Amelanchier (family Rosaceae) includes about 25 species of shrubs or small deciduous trees. The most popular species are Saskatoon berry (A. alnifolia), Canadian serviceberry (A. canadensis), juneberry (A. lamarckii) and snowy mespilus (A. ovalis)[1]. Saskatoon berry (A. alnifolia Nutt.), a fruit-bearing shrub, is native to the Prairie Provinces of Canada and northern plains in the United States of America [2,3]. The most popular cultivars of this plant species, mainly grown in Canada and the USA, are ‘Smoky’, ‘Honey- wood’, ‘Thiessen’, ‘Northline’ and ‘Martin’, which were brought to Poland in 2007. Recent research and observations showed that Saskatoon berry adapted well to Polish climatic and soil conditions and could be successfully cultivated in our conditions [4]. It can also grow in almost all soil types, except marshy sites and sands that are too dry and barren. Well-hardened shrubs withstand winter temperatures even down to −40 ◦ C, and the buds and flowers are tolerant to spring frosts. Moreover, this crop is also interesting for growers Agronomy 2023, 13, 520. https://doi.org/10.3390/agronomy13020520 https://www.mdpi.com/journal/agronomy