The effect of pre-cultured boron and calcium application on the success of micropropagation in apricots

In this study, three-year-old seedlings of the 42-25 apricot (Prunus armeniaca L.) genotype, previously identified in field studies conducted in Konya as superior in terms of rootstock characteristics and obtained through micropropagation at the Department of Horticulture, Selçuk University, were used as plant material. The study aimed to determine the effects of pre-culture applications of boron (150 and 300 ppm), calcium (1% and 2% CaCl₂), and their combinations on in vitro micropropagation and rooting success in this apricot genotype. Cuttings taken from plants sprayed with predetermined doses of Ca and B before culture were sterilized and transferred to MS nutrient medium. During the propagation phase, explants were subcultured regularly until a sufficient number was reached, continuing for a total of seven subcultures. Shoots showing healthy growth in each subculture were transferred to fresh medium. At this stage, plant viability, shoot number, shoot length, and vitrification rate were evaluated. In the rooting phase, rooting rate, root number, root length, and apical necrosis rate were examined. According to the findings, the highest shoot number was recorded in the control group (9.40 shoots/explant), whereas the longest shoots were obtained from the 300 ppm B treatment. The highest vitrification rate was also observed in the 300 ppm B treatment; however, vitrification was completely prevented in 1% CaCl₂ and some combination treatments. Rooting rate reached 100% in all treatments, including the control, while root number was particularly higher in 1% CaCl₂ and control treatments. Root length reached its maximum levels in 1% CaCl₂ and its combinations. Additionally, the lowest apical necrosis rate was recorded in the 1% CaCl₂ treatment, indicating a strong suppressive effect.