Floral phenology of nine poinsettia varieties (Euphorbia pulcherrima Willd. ex Klotzsch).

Abstract

Most phenological studies focus on the observation of changes in the morphology of the plant, with relatively rapid appearance, transformation or disappearance of certain organs or different events, which are called phenological phenomena. The interval between two events or phenological phenomena defines a phenological state or development phase of plants. The objective of this work was to document the floral phenology of poinsettia and its anatomical changes, to define aspects related to genetic improvement. Three varieties of poinsettia and six shade cultivars were studied. The recording of the observations of the phenological phases of flowering began with the pigmentation of the central midrib of the bract, which shows the beginning of the reproductive phase, daily observations were made to describe the successive phenological changes until the formation of fruits; The international Biologische Bundesanstalt, Bundessortenamt und Chemische (BBCH) scale, which provides a decimal coding system, was used to describe the different phenological stages. The duration of flowering was recorded (in days). The duration of flowering differed in each of the phenological stages among varieties. On the sun poinsettias the onset of the ciatus development occurs in an ascending manner, while on the shadow poinsettias it occurs in descending manner. The results allowed documenting the floral phenology with which, in later works, a genetic improvement program can be established that allows for crossbreeding between varieties