Agronomy and Horticulture, Department of


First Advisor

Katherine Frels

Second Advisor

P. Stephen Baenziger

Third Advisor

Jinliang Yang

Date of this Version

Fall 12-2-2022

Document Type



Jimenez, J. (2022). Deciphering The Genetic Architecture of Key Female Floral Traits for Hybrid Wheat Seed Production. Theses, Dissertations, and Student Research in Agronomy and Horticulture. University of Nebraska Lincoln.


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 (Plant Breeding and Genetics), Under the Supervision of Professor Katherine Frels. Lincoln, Nebraska: December, 2022

Copyright © 2022 Juan David Jimenez Pardo


Wheat (Triticum aestivum L.) is a staple cereal that provides 20% of the calories and proteins in human intake (Ray et al., 2013). Global population is projected to increase to 9.7 billion by 2050. Food production must increase by 70% to feed this future population. Wheat production is in crisis due to political and environmental challenges and is projected to decline by 0.8% in 2022 (FAO, 2022). To ensure food security yield genetic gain must increase by around 1.4% annually. Taking advantage of heterosis, hybrid wheat has the potential to boost grain yield. However, hybrid wheat seed production systems are not profitable due to the cleistogamy of the crop (Longin et al., 2012). Selection of parental lines with beneficial floral traits is necessary to improve outcrossing ability and thus seed set in hybrid wheat production fields. While several studies have focused on the morphological and genetic variation of male floral traits, few have studied in detail the phenotypic and genetic architecture of female floral traits and their crucial importance in hybrid wheat seed production systems. This study aims to unravel the genetic architecture of key female floral traits for hybrid wheat seed production by phenotyping key female floral traits and conducting a genome wide association study to decipher the genetic basis of the phenotyped traits. We studied a panel of winter wheat breeding lines sprayed with the Chemical Hybridizing Agent Croisor®100. Gape Date, Gape Score, and CHA damage were measured during seven years and genotyped with 44,240 SNP markers. The phenotypic variation was very wide for all female traits in the phenotyped lines. We identified 73 significant marker-trait associations for all assessed traits. Three candidate genes coding for unknown proteins were the most promising and their specific biological function need to be explored. The understanding of the genetic architecture of the female floral traits, and the identified marker-trait associations and candidate genes in this study might serve as a foundation for future studies on developing female floral traits to enhance cross-pollination for effective hybrid wheat seed production.

Advisor: Katherine Frels