Factors influencing rooting in cutting propagation of cypress (Cupressus sempervirens L.)

Some aspects related to the rooting of cuttings of Cupressus sempervirens w ere examined in this work. They are of both scientific and practical releva nce, dealing with the genetic variability of the rooting ability, the expre ssion of this character in different periods of the year and the efficiency of the modality of hormone supplying. A greater efficiency of indole-butyr ic acid given to the cuttings in the form of either potassium salt solution or talcum dispersion were found, compared to the alcoholic solution. The d ifferent treatments did non affect the number of adventitious roots per cut ting and the mean root length. A strong variability in the rootability of cuttings was found among differe nt genotypes. In an experiment performed on April with 20 selected clones, the rooting percentage of the K-IBA-treated cuttings ranged between 0% and 88%, with most of the clones showing a rooting potential below 30%; in the same trial the best-rooting clone gave 34% rooting of nontreated cuttings. In another experiment performed on December the rooting was very poor for a ll the clones tested, whether for the treated or for the untreated cuttings . With three clones characterised by a different rooting potential, the roota bility of cuttings was detected, along the best rooting season, making a se ries of tests in which cuttings were collected at short intervals. A charac teristic trend in the ability to root, in terms of natural and induced root potential and, particularly, in the expression of this potential along the period studied was observed in the clones tested.