747 SEEDS OF MALUS TRILOBATA Yilmaz, M. (2008), Seed Sci. & Technol., 36, 747-756 Optimum germination temperature, dormancy, and viability of stored, non-dormant seeds of Malus trilobata (Poir.) C.K. Schneid. M. YILMAZ KSU Faculty of Forestry, Department of Silviculture, Kahramanmaras, Turkey, 46060 (E-mail: mustafayilmaz@ksu.edu.tr) (Accepted April 2008) Summary Studies were made to determine the optimum germination temperature, depth of dormancy, and storability of non-dormant, prechilled Malus trilobata seeds from three altitudinal provenances (Kadirli, Önsen, and Bertiz) in the Eastern Mediterranean region of Turkey. The optimum germination temperature (based on seed germination percentage and speed) was 18°C and the seeds required about 12 weeks prechilling to break full dormancy. Germination of non-dormant, prechilled seeds, 7.5% moisture content, decreased by about 24% after 1 year of storage at 3°C. Introduction Deer or horse apple, Malus trilobata (Poir) C.K. Schneid., an Eastern Mediterranean species, is an interesting and rare tree species in Turkey (Browicz and Karaca, 1993). Deer or horse apple grows to 4–14 m in the height, has distinctive leaves and is found in South Anatolia, Thrace (Greece), Bulgaria, and Lebanon (Yaltırık, 1966; Browicz, 1982; Zahreddine, 2005). In Turkey, it mainly occurs at 350-1300 m altitude where it usually prefers sunny places on rocky, limestone-rich, or chalky soils. Both in its flowers and in leaves, M. trilobata is a very ornamental species (Browicz and Karaca, 1993). Branches and leaves are used to make a natural dye (Türkmen et al., 2004) as well. It is called as “at elması” (horse apple), “geyik elması” (deer apple), and “geyicek” in Kahramanmaras, Adana, and Mersin regions, respectively. In Turkey the number of M. trilobata has decreased dramatically as a result of their over use as firewood despite its sparse distribution since it is publicly perceived as a fruit tree rather than a forest tree. There is an increasing interest in using native local trees both for reforestation and urban plantings (Ürgenç, 1998; Grey and Deneke, 1992). Research on the seed physiology of this species is needed before widespread seedling production and ex-situ conservation of M. trilobata can be successfully carried out. Temperature is one of the most effective factors affecting the germination behavior of seeds (Bewley and Black, 1994; Schmidt, 2000). Temperature requirements of seeds for