Abstract
Fusarium verticillioides (FV) is a fungal maize pathogen that causes Fusarium ear rot (FER)
and contaminates the grains with fumonisins, a family of carcinogen mycotoxins. Maize genotypes
show quantitative genetic variations for resistance to FER and fumonisin B1 (FB1) accumulation.
Moreover both traits have moderate -high heritability. For these reasons Marker Assisted Selection
of resistant genotypes is an attractive approach to reduce the losses derived from this fungal
infection. The outcome of the infection is strongly influenced by environmental conditions and the
disease severity vary greatly among years. A careful phenotyping of the population has a central
role in a precise QTL mapping of traits related to resistance to FER and FB1 accumulation.
The resistant (CO441) and the susceptible (CO354) lines to FV infection were crossed and
generated 180 F2:3 segregant maize families. The population was evaluated for resistance to FER
and FB1 accumulation in two sowing times, early and late, of both 2011 and 2012. Phenotyping was
conducted on artificially inoculated F3 ears at 15 days after pollination with two methods (sideneedle,
inoculation with spores, and toothpick, inoculation with mycelium). FER resistance was
evaluated at maturity using a 1-7 rating of Fusarium infection on the ears, corresponding
respectively to 0 and 100% of the infected ear. FB1 accumulation in the grains was predicted by
NIR spectroscopy. In parallel, a molecular linkage map was constructed for the CO441xCO354
progeny (157 F3 DNA pools and the parents) using a Genotyping-by-Sequencing (GBS) approach
(PLoS ONE 6(5):e19379). Initial analyses identified 16.236 SNP markers. Stringent criteria for
SNP calling and filtering, segregation distortion and the setting of a threshold for missing data
generated a set of 339 SNPs. These markers were integrated with genotyping data from 72 SSRs to
construct a more dense linkage map. A total of 16 and 14 QTLs for FER resistance and FB1
accumulation were detected using MQM analysis, and 5 of them were overlapped between the two
traits. These small-moderate effect QTLs were mainly detected in 1, 2, 4-9 maize chromosomes.
| Original language | English |
|---|---|
| Title of host publication | Proceedings of the Joint Congress SIBV-SIGA |
| Pages | 12 |
| Number of pages | 1 |
| Publication status | Published - 2015 |
| Event | Joint Congress SIBV-SIGA - Milano Duration: 8 Sept 2015 → 11 Sept 2015 |
Conference
| Conference | Joint Congress SIBV-SIGA |
|---|---|
| City | Milano |
| Period | 8/9/15 → 11/9/15 |
Keywords
- Fusarium verticillioides
- Genotyping-by-Sequencing
- QTL mapping
- Zea mays