EFFECT OF HEAT TREATMENTS ON DIFFERENTIATION AND FLOWERING OF TUBEROSE (Polianthes tuberosa L.).

Abstract

Tuberose (Polianthes tuberosa L.) is an ornamental plant produced worldwide, mainly as a cut flower. A limitation of tuberose production is the control of flowering time, for which different strategies have been evaluated, one of these is the pretreatment of the corms with temperature. In this study, corms of tuberose were subjected to two storage temperatures (4 and 27 °C) for 4, 5, 6 and 7 weeks, in addition to two controls: corms kept at room temperature (T0) and corms with a pretreatment with GA₃
(200 ppm). The variables evaluated were meristem length (ML), meristem width (MW), days to sprouting (DS), days to flowering (D), flower stem length (FSL), flower stem diameter (FSD), spike length (SL) and number of flowers (NF). The fastest growth and differentiation of the meristem occurred after the establishment of corms in the greenhouse; treatments at 27 °C advanced the sprouting of the first leaves. The treatments of 27 °C for six weeks and 4 °C for one week showed fewer days to flowering
(100.8 and 104.0 respectively). In general, corms treated at 27 °C showed greater homogeneity in the harvest curve without affecting the rest of the variables evaluated, which is important because such treatments can be used to control tuberose flowering without affecting quality.