Agronomy and Horticulture, Department of


First Advisor

P. Stephen Baenziger

Date of this Version


Document Type



Garst, Nicholas. 2017. Assessing anther extrusion and its effect on US hard winter wheat (triticum aestivum L.) hybrid seed production. 1-37.


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Agronomy, Under the Supervision of Professor P. Stephen Baenziger. Lincoln, NE: March, 2017


The promise of higher grain yields as a result of the development and production of hybrid wheat (Triticum aestivum L.) has not been fully realized primarily due to the high cost of seed production. Anther extrusion is a key trait that improves pollen availability, and thus, is expected to enhance hybrid wheat seed production yields. Hard winter wheat germplasm adapted to the US Great Plains was visually assessed for anther extrusion in the field and greenhouse environments. Significant genotypic differences were detected and high broad-sense heritability was calculated (ranging from 0.62 to 0.85) for anther extrusion in the field. Over 50% of the genotypes were visually assessed as 5 or higher (1 lowest to 9 highest extrusion) in both 2014 and 2015. Visual ratings made in the greenhouse were not highly correlated (r=0.40*) with those made in the field, indicating that selection for anther extrusion should be conducted in the field. A chemical hybridizing agent, CROSOIR 100®, was used to induce male sterility and produce hybrid seed to determine the significance of anther extrusion on hybrid seed production. Hybrid seed yield as determined by weight was weakly correlated in 2015 (r=0.60*) but not significantly correlated in 2016 with anther extrusion, indicating that anther extrusion likely improves hybrid seed set. However, hybrid seed set results must also be interpreted while considering the phytotoxic effects of the CHA, and its possible impact based on genotype.