Flowering quality and regulation in azalea: interaction between genetic, physiologic and growth specific factors (AZALEABLOEI)

High flowering quality is extremely important for a flowering pot plant such as azalea. Non-optimal flowering is the unequal opening of the flower buds of a single plant or flower buds that remain closed after sale. This is not good for the image of the azalea as a high quality product. The azalea sector is increasingly confronted with problems related to flowering quality. The goal of this project is to determine the causal factors of this problem. Do the altered growth conditions of the last decade have an impact on this problem? Can we propose a charter for high quality growth and ensure higher flowering quality?

In several experiments azaleas are grown under different conditions. Each experiment stresses a specific growth phase (bud initiation, dormancy, anthesis). Test objects are studied using a multi-disciplinary approach. Flowering of the plants are evaluated by counting the number of flower buds. The physiological condition of the plants is also compared during different growth stages, e.g. by determining the amount of carbohydrates stored. Finally, the expression of a set of key genes is measured in the different growth stages. The combination of all of these data should demonstrate how specific growth manipulations influence flowering of the plants.

  

 

Project results confirm the existence of two factors that have a major impact on flowering quality. First, it is extremely important that plants are stored in the cold chamber at 7 °C for dormancy release. The exact timing for storing the plants has to be determined based on the stage of flower differentiation. Depending on the cultivar, 4 to 10 weeks of cold temperatures are needed for dormancy release. Second, carbohydrate metabolism plays an important role. Plants need a certain amount of starch to stimulate the opening of the flowers. For this reason, the presence of a sufficient amount of light during forcing is crucial. During forcing, starch is accumulated, which allows flowering later on in (dark) living areas. This project demonstrates this both genetically and physiologically. These results allow the grower to alter the growth of their azaleas in order to assure optimal flowering after sale of the plant.

 

Funding provider(s)
IWT - Instituut voor de aanmoediging door wetenschap en technologie in Vlaanderen

External partner(s)
PCS - Proefcentrum voor de Sierteelt
Ugent - Fac. Bio-ingenieurswetenschappen