Water-use efficiency, photosynthetic characteristics, and high through-put phenotyping methods for soybean (glycine max) genotypes contrasting in carbon isotope discrimination

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI-COLUMBIA AT AUTHOR'S REQUEST.] Drought is a huge concern for soybean growers across the world, and in the Midwestern US is the main limitation to grain yield. A way to protect against drought stress is for plants to use water more efficiently. Carbon isotope discrimination (CID) is a measured trait that is related to water-use efficiency (WUE), and can be used to screen genotypes for higher WUE. Several genotypes were studied in multiple greenhouse and field experiments with varying drought stress treatments. Genotypes exhibiting less CID were shown to have a higher WUE, and CID was related to WUE. The higher WUE genotypes also exhibited differences in photosynthetic traits, especially in their stomatal behavior to restrict water loss. In terms of grain yield, very few differences were observed between the genotypes. Thermal images to estimate canopy temperature and sap flow sensors to estimate field water use provided excellent insight into differences among watering treatments and genotypes for transpiration rates. This research demonstrates, that in soybean, CID can be used as a screening tool to select for higher WUE, and higher WUE is likely a result of increased stomatal restrictions to prevent water loss during periods of drought stress. However, these genotypes exhibiting less transpiration showed minimal, if any grain yield reduction. Further, whole field imaging can also be utilized to identify higher WUE genotypes, and sap flow sensors can be expected to estimate water use in the field. Both resulting in reduced labor and more efficient time use.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Plant sciences (MU)

Grantor dc:publisher

University of Missouri--Columbia

Year dc:date.issued

2016

Author dc:creator

• Naylor, Brett

Advisor dc:contributor.advisor

• Fritschi, Felix B., 1969-

Statement dc:rights

• Access to files is limited to the University of Missouri--Columbia with SSO login.

Language dc:language.iso

eng, English

DOI

https://doi.org/10.32469/10355/60389

OAI identifier oai:identifier

oai:mospace.umsystem.edu:10355/60389