Reza Ghahremani - MSc graduated, Tissue culture specialist, Department of Horticultural Science, Collegeof Aburaihan, University of Tehran, Tehran, Iran
Naser Askari - Assistant Professor, Tissue culture specialist, Department of Horticulture, University ofJiroft, P.O. Box ۳۶۴, Jiroft, Iran

Adventitious root induction is one of the basic steps in micropropagation of apple rootstocks. Light quality play key role on new adventitious roots initiation. We explored the efficacy of jelly food coloring (red, blue and purple) on rooting percentage, the numbers of roots and root length in MM.۱۱۱ rootstock as a model plant, at the first time. We established that colored medium improves adventitious root formation, and found that this results can recommend for other rootstocks in rooting phase. In general, red culture medium had the highest percentage of root induction and also the number of roots. On the other hand, the results showed that it is necessary to combine both red and blue color (purple) for maximum increase in the root length of shoot explants.

Adventitious root; apple rootstock; colored medium; light quality