Variation among and within clones in formation of roots and shoots during micropropagation of Campanula isophylla

Abstract

It is known that treatments enhancing shoot formation often suppress root formation and vice versa. It would be of interest to know if such negative correlations between formation of roots and shoots were also present among genetically different plants, given the same treatment, to ensure that selection for superior shoot formation would not lead to inadvertent decreases in the capacity for root formation. Height and dry weight of micropropagated shoot clusters and the numbers of shoots and roots were measured in 95 seedling clones. Within clones, shoot size was negatively correlated with number of shoots and positively correlated with number of roots. Among clones, however, the number of shoots was not correlated with the size of shoots, but positively correlated with the number of roots. While it is difficult to devise treatments that simultaneously optimize the initiation of roots and shoots, it is thus possible to select for fast-growing clones without compromising root formation.