Degree Type


Date of Award


Degree Name

Master of Science


Genetics, Development and Cell Biology


Genetics and Genomics

First Advisor

Erik W. Vollbrecht


Inflorescence architecture in Zea mays is affected by a large collection of interrelated genes. The ramosa genes are some of the most prominent and well-studied of these genes due to their overtly branched ear and tassel mutant phenotype. ramosa1 confers determinate, short-branch identity on branch meristems during their initiation. Several new genes are proposed to work directly with ramosa1. ail6 was identified from a Quantitative Trait Locus study to identify genes which enhance or suppress the ramosa1 branching phenotype. A Yeast-2-Hybrid study identified several genes as potential interactors with ramosa1. A CRISPR/Cas9 knockout study was performed to produce novel mutants to analyze this pathway. Two unique CRISPR expression arrays were utilized targeting 12 sites in five genes. Agrobacterium tumefaciens mediated transformation was used for transfection of Hi-II immature embryos. Both arrays functioned, and mutations were acquired in all five genes. Specifically, thirteen unique mutations have been detected in the ramosa1 gene, and in the other four genes we detected eight, 16, four and one mutation. A total of 112 plants were recovered and crossed into a B104, B73 or B73 ra1-63 background.

Copyright Owner

Ryan James Arndorfer



File Format


File Size

102 pages