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Tropentag, September 14 - 16, 2022, Prague

"Can agroecological farming feed the world? Farmers' and academia's views."


Genotype × environment effects on leaf properties and pigment composition in wheat under water deficit

Ilaria Parente1, Geckem Dambo1, Alejandro Pieters1, Francisco Pinto2, Folkard Asch1

1University of Hohenheim, Inst. of Agric. Sci. in the Tropics (Hans-Ruthenberg-Institute), Germany
2CIMMYT Mexico, Remote Sensing, Mexico


Abstract


Wheat growing environments are increasingly characterised by extreme temperatures and reduced water availability. These conditions can potentially result in photooxidation of pigment-protein complexes and chloroplasts components, which will lead to decreased of photosynthesis and growth. Thus, identification of high-performing and stress resilient wheat germplasms is pivotal. Photoprotection can contribute a large share to achieving such resilience as it is the interface between efficient use of absorbed light in photosynthesis and the safe dissipation of excess light energy. However, a complete understanding of the adaptive response of the wheat photoprotection system to water deficit during crop development is missing. The purpose of this research was to identify changes in leaf hyperspectral reflectance at different crop developmental stages for the youngest fully expanded leaf and the third leaf. Thirteen wheat genotypes from the Best PT panel developed by CIMMYT, were grown in the field at CIMMYT research station in Obregon, Mexico, and exposed to two different environments: drought and potential yield. The drought environment was irrigated at sowing, 50% emergency and at the initiation of booting, whereas the potential yield environment was irrigated at sowing, 50% emergency and every fourteen days but reduced to nine days towards maturity. The lines were selected according to their contrasting evapotranspiration performance, estimated through canopy temperature measurements, and estimation of yield in previous water deficit experiments in the field. Using frequent sensor-based methods, we studied the temporal dynamics of spectral indexes, including NDVI, NPCI, PRI and relative chlorophyll content measured with SPAD. The lines studied showed contrasting patterns for the different physiological indexes at different growth stages. These results will be corroborated in the laboratory by HPLC analysis of leaf samples. These results will be linked to soil humidity and canopy temperature. These findings can lead to the characterisation of the dynamics of photoprotection mechanisms in wheat, which can be incorporated into a field-based screening tool for high-throughput phenotyping. 


Keywords: Photoprotection, reflectance indexes, water deficit, wheat


Contact Address: Ilaria Parente, University of Hohenheim, Inst. of Agric. Sci. in the Tropics (Hans-Ruthenberg-Institute), Fruwhirtsrasse 11, 70953 Stuttgart, Germany, e-mail: ilaria.parente@uni-hohenheim.de


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