Methodological aspects and impact on grain weight of source reduction through shade meshes during grain filling of bread wheat

MAYDUP, MARIA L.; ANTONIETTA, MARIANA; ROUILLET, NICOLÁS; CANO, MARIA G.; GUIAMET, JUAN J.; TAMBUSSI, EDUARDO A.

Crop and Pasture Science

CSIRO Publishing

Año: 2020 vol. 71 p. 739 - 751

1836-0947

In crop studies, shading is a common approach for reducing source activity (i.e. assimilates produced by photosynthesis); however, if source reduction is not directly proportional to the degree of light attenuation, estimations could be flawed. We analysed the effects of shading at three levels on light transmittance, air and canopy temperatures, and actual photosynthetic activity at different times of day, and on grain weight in a modern genotype of bread wheat (Triticum aestivum L.). The treatments were imposed 10 days after anthesis and comprised three levels of shading with meshes: 80%, 50% and 10% transmittance during midday. The decrease in midday photosynthetic activity (electron transport rate, ETR; and CO2 assimilation, An) in the shading treatments compared with control plants did not fit a 1 : 1 relationship with light transmittance of the meshes; for example, the reduction in ETR and An was