Universität Bonn

INRES Crop Science

Leaf photosynthesis responses of old and modern wheat cultivars under varying soil N conditions

Master Thesis

Research area

Crop science

Motivation / State of the art / Relevance

With “Farm-To-Fork” strategy, the European farmers must reduce around 20-30% nitrogen application to crops by 2030 due to its negative environmental impacts (e.g. N leaching and contaminated ground water) while they need to sustain further crop productivity. Findings of cultivars that are suitable to low N or optimized N applications thus are important in this context. Photosynthesis traits were one of the most important traits that have been targeted in the past to improve the nitrogen use efficiency and crop yield. However, degree of importance of photosynthesis traits varied depending on cultivars and N conditions. Understanding how N distributions from soil to different organs (leaf and stems) and their relations to photosynthesis thus are important to identify optimal N application doses and suitable cultivars as well as improvement of current crop models in simulating N dynamics.


The aim of the study are to (i) quantify the N concentration and dynamics from soil to stem and leaf (ii) quantify crop physiological traits (stomatal conductance, maximum carboxylation rate of Rubisco, and photosynthesis); and (iii) to analyze and understand the correlations of dynamic N with the photosynthesis traits.

Methodology / Procedure / Workscope / external cooperation

This work will base on the field trial with different cultivars and N applications. Students will have an opportunities to work in the well-designed field trial with different old and modern cultivars under contrast soil N conditions as well as different measuring methods (destructive and sensing techniques) in the laboratory and field. Student is also supposed to perform statistical analysis in understanding relations of various crop traits and relevant environmental factors.

Expected results

Cultivars variations in crop photosynthesis responses to N


02/2024 – 09/2024


English or German

Previous knowledge

Interests in crop phenotyping, photosynthesis, N application


Dr. Thuy Nguyen, Dr. Thomas Gaiser



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