Degree Type


Date of Award


Degree Name

Doctor of Philosophy



First Advisor

Michael Lee

Second Advisor

Kendall R. Lamkey

Third Advisor

Erik W. Vollbrecht


Popcorn and dent maize are distinct gene pools and are maintained and utilized as such in maize breeding programs. Popcorn is inferior to dent maize in traits related to crop productivity. Dent maize is a potential source of favorable alleles to improve the productivity of popcorn, but its utility is hindered by dent alleles with negative effects on popping expansion volume (PEV). If the genetic architecture of popping expansion and other important traits is known in dent x popcorn populations, the negative effects of dent germplasm on PEV may be minimized by marker-assisted selection. Use of DNA markers in breeding programs requires that quantitative trait loci (QTL) associated with target traits be identified. QTL for PEV, kernel weight (KW), growing degree units to anthesis (GDU), and plant height were mapped in F2 plants and their F2:3 families in a dent (B104) x popcorn (BP3) population. Seven QTL associated with 82% of the phenotypic variance were detected for PEV on chromosomes 1 (bins 1.05 and 1.07), 2, 3, 5, 8, and 9. The BP3 allele increased PEV at all QTL except on chromosome 8 where the B104 allele increased PEV. QTL for KW were detected on chromosomes 1 (bins 1.03 and 1.05), 6, 7, 8, and 9. The B104 allele increased KW at all QTL. GDU QTL were detected on chromosomes 1, 2, 3, 4, 6, and 8. For plant height, QTL were detected on chromosomes 1, 2, 8, and 9. QTL for GDU and plant height were in regions where QTL affecting flowering time and plant height were detected in previous studies conducted in dent and flint maize populations. In addition, GDU and plant height QTL were also in regions where genes and other genetic factors affecting both traits have been mapped in maize.



Digital Repository @ Iowa State University,

Copyright Owner

Thanda Dhliwayo



Proquest ID


OCLC Number




File Format


File Size

115 pages