|Eller, M -|
|Payne, G -|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 28, 2010
Publication Date: November 15, 2010
Citation: Eller, M.S., Payne, G.A., Holland, J.B. 2010. Selection for Reduced Fusarium Ear Rot and Fumonisin Content in Advanced Backcross Maize Lines and Their Topcross Hybrids. Crop Science. 50:2249-2260. Interpretive Summary: Fusarium verticillioides is a fungus that infects corn, causing kernels and ears to rot. This fungus also can produce a toxin that is harmful to animal and human health in corn grain. Breeding for resistance to infection by this fungus is hampered by the complex inheritance of resistance – resistance is controlled by many genes and is subject to environmental influences. This study demonstrates that even with such complexity, traditional breeding approaches can improve the level of resistance available in a corn inbred that was recently important for producing commercial maize hybrids in the USA. We crossed this elite line to an older line with poor agronomic performance but higher levels of Fusarium ear rot resistance. After several generations of controlled pollinations and selection, we developed new inbred lines that have higher levels of resistance than the commercial line but maintained its yield potential and agronomic quality. The success of such breeding programs is highly dependent on obtaining accurate disease evaluations in the field, which is made more likely by increasing the numbers of locations and years under which the lines are screened.
Technical Abstract: Backcross breeding is an important method to improve elite cultivars for traits controlled by a small number of loci but has been used less frequently to improve quantitatively controlled traits. Resistances to Fusarium ear rot and contamination by the associated mycotoxin fumonisin in maize are quantitatively inherited. We backcrossed the more resistant but unadapted inbred GE440 for four generations to the susceptible but agronomically elite commercial inbred FR1064. A selected set of 19 BC4F1:3 lines had greater resistance to ear rot and fumonisin content that their recurrent parent FR1064. Topcrosses of the selected lines had greater resistance to Fusarium ear rot and similar grain yield compared to the topcross of the recurrent parent FR1064. We also genotyped selected lines at DNA markers linked to ear rot and fumonisin resistance quantitative trait loci (QTL) identified in the BC1 generation of this cross to determine which QTL demonstrated allele frequency shifts due to selection. Markers linked to QTL on chromosomes 1 and 4 inherited the GE440 allele significantly more often than expected by random chance.