Rootstock-Induced Dwarfing and Yield Efficiency in Apricot: Performance of SP-2 (Prunus spinosa) and DO-1,2,3 (Prunus Domestica)

Propagation of fruit trees is typically achieved through vegetative methods due to their long juvenile period. Common vegetative propagation techniques include cuttings, grafting, and in vitro micropropagation. Grafting involves the union of two distinct plant parts to form a symbiotic organism. The root system, or rootstock, significantly influences the growth and yield characteristics of the grafted scion cultivar. Therefore, selecting appropriate rootstocks is critical in fruit production. Among stone fruits, wild plums (Prunus spp.) and their hybrids are the most widely used rootstocks, primarily due to their tolerance to extreme soil conditions and ease of vegetative propagation. Kahramanmaraş region, located within the natural distribution range of many stone fruit species, has been the focus of a comprehensive rootstock selection program initiated in 2009. This effort identified approximately 50 promising wild plum genotypes, which were incorporated into breeding studies. Among these, SP-2 (P. spinosa), known for its dwarfing effects, and DO-1, DO-2, and DO-3 (P. domestica), recognized for their high compatibility with apricots, were examined in detail. This study evaluated the effects of these rootstocks on tree growth, yield, and fruit quality parameters in table apricot cultivars. The research, conducted between 2015 and 2021 at the Eastern Mediterranean Transitional Zone Agricultural Research Institute, revealed that SP-2 exhibited the smallest trunk cross-sectional area (TCSA) at 6.55 cm², indicating a pronounced dwarfing effect. Most vigorous development was observed in the Myrobolan 29C (7.34 cm) in the study. Fruit weight ranged from 35.81 g to 40.09 g, with the highest observed in apricots grafted onto DO-1, comparable to Myrobolan 29C. Other fruit quality parameters showed no statistically significant differences between the candidate and control rootstocks. In conclusion, the tested rootstocks exhibited a significant dwarfing effect while maintaining yield and quality parameters consistent with the literature. These findings will inform future rootstock breeding programs.