Increased root and shoot production during micropropagation of cherry and apple rootstalks: effect of subculture...

Shoot cultures of apple rootstock cv. M9 and cherry rootstock cv. F12/1 were established and then divided into several sub-lines that were subcultured at 28-42-day intervals. Consequently, similarly aged cultures received various numbers of subcultures. Cultures kept at 24 degrees C showed an increase in shoot and root production over time. There were differences in shoot and root production between apple lines, but there were no differences among sub-lines. In cherry, altering the subculture interval affected rooting competence, which increased with time. Cherry cultures maintained at 4 degrees C gave rise to cultures that were as easy to root as cultures kept at 24 degrees C with more frequent subculturing. We conclude that total time in culture is the most important factor bringing about physiological changes in these genotypes of micropropagated apple and cherry.