Originally published as Genetics Published Articles Ahead of Print on March 4, 2007.

Genetics, Vol. 176, 625-644, May 2007, Copyright © 2007
doi:10.1534/genetics.106.064493

Classical Genetic and Quantitative Trait Loci Analyses of Heterosis in a Maize Hybrid Between Two Elite Inbred Lines

Elisabetta Frascaroli*,1, Maria Angela Canè*, Pierangelo Landi*, Giorgio Pea{dagger}, Luca Gianfranceschi{dagger}, Marzio Villa{dagger}, Michele Morgante{ddagger} and Mario Enrico Pè{dagger}

* Department of Agroenvironmental Sciences and Technologies, University of Bologna, 40127 Bologna, Italy, {dagger} Department of Biomolecular Sciences and Biotechnology, University of Milano, 20133 Milano, Italy and {ddagger} Department of Crop Sciences and Agricultural Engineering, University of Udine, 33100 Udine, Italy

1 Corresponding author: University of Bologna, DiSTA, Viale Fanin, 44, Bologna 40127, Italy.
E-mail: elisabetta.frascaroli{at}unibo.it

The exploitation of heterosis is one of the most outstanding advancements in plant breeding, although its genetic basis is not well understood yet. This research was conducted on the materials arising from the maize single cross B73 x H99 to study heterosis by procedures of classical genetic and quantitative trait loci (QTL) analyses. Materials were the basic generations, the derived 142 recombinant inbred lines (RILs), and the three testcross populations obtained by crossing the 142 RILs to each parent and their F1. For seedling weight (SW), number of kernels per plant (NK), and grain yield (GY), heterosis was >100% and the average degree of dominance was >1. Epistasis was significant for SW and NK but not for GY. Several QTL were identified and in most cases they were in the additive–dominance range for traits with low heterosis and mostly in the dominance–overdominance range for plant height (PH), SW, NK, and GY. Only a few QTL with digenic epistasis were identified. The importance of dominance effects was confirmed by highly significant correlations between heterozygosity level and phenotypic performance, especially for GY. Some chromosome regions presented overlaps of overdominant QTL for SW, PH, NK, and GY, suggesting pleiotropic effects on overall plant vigor.




This article has been cited by other articles:


Home page
 GeneticsHome page
M. Radoev, H. C. Becker, and W. Ecke
Genetic Analysis of Heterosis for Yield and Yield Components in Rapeseed (Brassica napus L.) by Quantitative Trait Locus Mapping
Genetics, July 1, 2008; 179(3): 1547 - 1558.
[Abstract] [Full Text] [PDF]

Home page
 GeneticsHome page
A. E. Melchinger, H. F. Utz, and C. C. Schon
Genetic Expectations of Quantitative Trait Loci Main and Interaction Effects Obtained With the Triple Testcross Design and Their Relevance for the Analysis of Heterosis
Genetics, April 1, 2008; 178(4): 2265 - 2274.
[Abstract] [Full Text] [PDF]

Home page
 GeneticsHome page
A. E. Melchinger, H. F. Utz, H.-P. Piepho, Z.-B. Zeng, and C. C. Schon
The Role of Epistasis in the Manifestation of Heterosis: A Systems-Oriented Approach
Genetics, November 1, 2007; 177(3): 1815 - 1825.
[Abstract] [Full Text] [PDF]

Home page
 GeneticsHome page
B. Kusterer, H.-P. Piepho, H. F. Utz, C. C. Schon, J. Muminovic, R. C. Meyer, T. Altmann, and A. E. Melchinger
Heterosis for Biomass-Related Traits in Arabidopsis Investigated by Quantitative Trait Loci Analysis of the Triple Testcross Design With Recombinant Inbred Lines
Genetics, November 1, 2007; 177(3): 1839 - 1850.
[Abstract] [Full Text] [PDF]