The effect of the cutting method on rooting of Dahlia pinnata Cav. cuttings

Dahlias are propagated through stem cuttings. In the years 2003–2005, in a glasshouse of the Experimental Station in Felin, University of Life Sciences in Lublin, the research was conducted to evaluate rooting of different types of dahlia cuttings. The studied Dahlia pinnata cultivars were: ‘Berliner Kleene’, ‘Gea’, ‘Orange’ and ‘Orietta’. Six types of cuttings were tested: cuttings with heel, without heel, tip ones, tip long ones, lateral and middle ones. The cuttings excision was started when sprouting shoots had 5–7 pairs of leaves. The tip part with 2–3 pairs of leaves was cut off, leaving at least 2 pairs of leaves on the stem (tip cuttings). After about 2 weeks, in the nodes, new shoots start to arise, which might be used as cuttings when they form 2–3 pairs of leaves. When the tip cuttings are excised, new shoots will sprout directly from a tuber. They might be excised with a part of a tuber as cuttings with heel or without it – cuttings without heel. It is also possible to place tuberous roots into a glasshouse early, let the sprouting shoots form 6–8 pairs of leaves, and then excise longer then before tips with 3–4 pairs of leaves (long tip cuttings). The remaining, middle parts of the stems with 2 pairs of leaves, might be also used as lateral cuttings. Different types of cuttings were used and all of them rooted very well. No matter the type of cutting, their survival exceeded 90%. The types of cuttings did not significantly affect the percentage of rooted cuttings. However, the intensity of taking the roots depended on the cutting method. The growth started the earliest in case of cuttings with heel and tip ones. Plants formed from these types of cuttings characterized with the highest weight of the underground part as well. During the three years of the experiment, the highest mean weight of the above ground part was observed in case of tip and long tip cuttings.