Does light spectrum influence fruit set in sweet pepper?

Fruit set indicates the initiation of fruit growth derived from flowers, and the cessation of this process is termed as abortion. Fruit set is a crucial development process in the plant life cycle, and it is also a main determinant of crop yield. In sweet pepper, up to 80% of all flowers can abort. This results in a low yield as well as a strong cyclical pattern in fruit set, where periods with high fruit set are alternated with periods with low fruit set, causing unstable market supply and product price.

Fruit set/abortion is responding to various environmental signals, where light quality could be an important factor. However, this has hardly been studied so far. From preliminary experiments, supplementary far-red light reduced fruit set in sweet pepper, however its mechanism is still unknown. Multiple questions are addressed: Is this process related to hormonal balance (e.g., auxin, ethylene) in shade avoidance syndrome? Does FR promote fruit sink strength of sweet pepper? Is the low PSS (phytochrome photostationary state) achieved by high blue: red ratio has the same effect on fruit set as adding FR? More questions can be put forward after discussion with supervisors.

To investigate these questions above, we will set up and conduct greenhouse/climate chamber experiments, collect and analyze plant tissue samples in labs. With the completion of this study, the students are expected to have deeper understanding on plant reproductive development, and the interaction between plant and light environment.

Used skills

  • Destructive and non-destructive morphological measurements in greenhouse and/or climate room
  • Light spectrum measurement
  • Light microscope (depends on the specific topic)
  • Plant hormone determination (depends on the specific topic)
  • Sugar analysis (depends on the specific topic)
  • Gene expression analysis (qPCR) (depends on the specific topic)

Interested in doing a BSc or MSc thesis at HPP? Please contact the HPP student coordinator Katharina Hanika.