The infuence of Imidazole fungicides on multiplication in vitro of pyrodwarf pear rootstock

Pyrodwarf, low vigorous pear rootstock was used as a model plant in these investigations. Under the in vitro conditions, successful micropropagation of this genotype is largely based on the nodal transplantation of shoots due to low potential of lateral shoots to form. Therefore, the objective of these investigations was to study the influence of imidazole fungicide Prochloraz on the multiplication. The commercial chemical SPORTAK 45-E-450, which contains active substance Prochloraz (N-propyl-N-[2-(2,4,6-trichlorphenoxy)-ethyl]imidazole-1-carboxamide), was used as the source of the imidazole fungicide. The experiment was performed during the multiplication phase, and it involved the study of 19 types of media which included MS macro and micro salts, different prochloraz concentrations, BAP, IBA and GA3. Prochloraz involved 3 concentrations (1, 5 and 10 μM), either individually or combined with BAP (4.4 μM), IBA (5 μM) and GA3 (0.3 μM). Upon the second subcultures, the parameters of the shoot multiplication, multiplication index and the length and the number of leaves on axial and lateral shoots were determined. Fresh and dry shoot weight, i.e. callus, stem and leaves were also checked. The highest multiplication index (1:2.72) was obtained at the medium which contained 10 μM of prochloraz combined with 4.4 μM BAP and 0.3 μM GA3, individual multiplication index being even up to 1:6. Individual or IBA combined application of fungicides affected the shoot rooting of the Pyrodwarf (up to 100%). The obtained results suggest that Prochloraz intensifies the effect of the added exogenous BAP on in vitro multiplication of the Pyrodwarf pear rootstock and could be recommended for micropropagation of this rootstock