THE EFFECT OF TEMPERATURE REGIMES ON MICROPROPAGATION EFFICIENCY AND FIELD PERFORMANCE OF EUSTOMA GRANDIFLORUM

For most of the floricultural areas of Italy the low yield of flowers in the first year of the biennial cycle is a limiting factor to the extension of the cultivation of Lisianthus (Eustoma grandiflorum) for cut flower production.
The insufficient yield is depending on the late period of availability of the local seed propagated plants and on the suspencion of flowering in October.
Micropropagated plants had been already tested to evaluate the possibility to increase the first year production and to improve the quality of the flowers.
In this previous experiment plants obtained by direct rooting of cuttings from "in vitro" mother plants showed a reduced yield.
A specific study was started to investigate the effect of the temperature regimes imposed during the micropropagation phases.
The data prove that the lack of blooming and the delay of flowering are the result of the too high temperature level (24 or 18 °C) during the multiplicative phase.
A "normal" behaviour of the plants was veryfied in 3 clones out of 4 for the multiplication with a thermoperiod of 18/10 °C. The highest multiplication rate was found with 24 ° C temperature.
A certain clone-specificity regarding the main productive and propagative aspects was pointed out for each temperature regime tested.
Some interesting aspects concerning the tendency to bloom in fall/winter months of the micropropagated plants are discussed.

II International Symposium on the Development of New Floricultural Crops

E. Farina, B. Ruffoni

Lisianthus, cut flower, heat stress, growth, clones

https://doi.org/10.17660/ActaHortic.1993.337.9