Spatial distribution of Fusarium Head Blight pathogens and associated mycotoxins in wheat fields

Most studies of Fusarium head blight (FHB) focused on wheat infection at anthesis. Less is known about infections at later stages. In this study, the effect of infection timing on the development of FHB and the distribution of fungal biomass and deoxynivalenol (DON) along wheat spikes was investigated. Under greenhouse conditions, two wheat varieties were point-inoculated with Fusarium graminearum starting from anthesis until 25 days after anthesis. The fungus and fungal DNA were isolated from the centers and the bases of all the spikes but not from the tips for all inoculation times and both varieties. In each variety, the amount of fungal DNA and the content of DON and deoxynivalenol-3-glucoside (DON-3-G) were higher in the center than in the base for all inoculation times. A positive correlation was found between the content of fungal DNA and DON in the centers as well as the bases of both varieties. This study showed that F. graminearum grows downward within infected wheat spikes and that the accumulation of DON is largely confined to the colonized tissue. Moreover, F. graminearum was able to infect wheat kernels and cause contamination with mycotoxins even when inoculated 25 days after anthesis.

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Meso- and Microscale Patterns of Fusarium Head Blight in Spring Wheat Fields in Minnesota

Plant Disease ◽

10.1094/pd-89-0474 ◽

2005 ◽

Vol 89 (5) ◽

pp. 474-479 ◽

Cited By ~ 5

Author(s):

K. P. Wilhelm ◽

R. K. Jones

Keyword(s):

Spatial Distribution ◽

Fusarium Head Blight ◽

Spring Wheat ◽

Disease Incidence ◽

Optimal Number ◽

Random Pattern ◽

Head Blight ◽

Frequency Distributions ◽

Previous Crop ◽

Regional Disease

Several techniques were used to study the spatial distribution of Fusarium head blight (FHB) in spring wheat fields in the Red River Valley of Minnesota in 2001 and 2002. Four scales of study were analyzed, ranging from countywide comparisons down to adjacent heads. Agreement to frequency distributions and the departure from randomness, along with the autocorrelation of FHB clusters, were calculated at each scale. Regression analysis also was used to describe any edge affects that might exist. Finally, the optimal number of samples to adequately assess a 32.4-ha (80-acre) field was determined to a precision of ±5% disease incidence (DI). The analysis showed that DI had a random pattern at scales smaller than 32.4-ha fields, including quadrats of 6,561, 729, and 9 m2, as well 0.8-m transects involving consecutive heads within drill rows. There was no difference in DI associated with edges of fields compared with the incidence of FHB in transects within fields. Analysis of the spatial distribution at the mesoscale (county and township) showed no association in FHB DI between fields based on proximity. Differences were attributed to previous crop and in-field residue. Disease incidence was most accurately assessed on a field-by-field basis. The optimal sampling size (with <5% error) for surveying for the incidence of FHB in a standard commercial field was seven 20-head samples. Regional disease estimates would improve from including more fields at the expense of fewer samples per field.

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Comparing Genetic Variation within Red Winter Wheat Populations with and without Image-Based Optical Sorter Selection

Al-Qadisiyah Journal For Agriculture Sciences (QJAS) (P-ISSN 2077-5822 E-ISSN 2617-1479) ◽

10.33794/qjas.vol9.iss2.82 ◽

2019 ◽

Vol 9 (2) ◽

pp. 266-277

Author(s):

Hussein M. Khaeim ◽

Anthony Clark ◽

Tom Pearson ◽

Dr. David Van Sanford

Keyword(s):

Genetic Variation ◽

Fusarium Head Blight ◽

Heading Date ◽

Fusarium Head Blight Resistance ◽

Gibberella Zeae ◽

Mass Selection ◽

Head Blight ◽

Red Winter Wheat ◽

Two Populations ◽

Head Scab

Head scab is historically a devastating disease affecting not just all classes of wheat but also barley and other small grains around the world. Fusarium head blight (FHB), or head scab, is caused most often by Fusarium graminearum (Schwabe), (sexual stage – Gibberella zeae) although several Fusarium spp. can cause the disease. This study was conducted to determine the effect of mass selection for FHB resistance using an image-based optical sorter. lines were derived from the C0 and C2 of two populations to compare genetic variation within populations with and without sorter selection. Our overall hypothesis is that sorting grain results in improved Fusarium head blight resistance. Both of the used wheat derived line populations have genetic variation, and population 1 has more than population 17. They are significantly different from each other for fusarium damged kernel (FDK), deoxynivalenol (DON), and other FHB traits. Although both populations are suitable to be grown for bulks, population 1 seems better since it has more genetic variation as well as lower FDK and DON, and earlier heading date. Lines within each population were significantly different and some lines in each population had significantly lower FDK and DON after selection using an optical sorter. Some lines had significant reduction in both FDK and DON, and some others had either FDK or DON reduction. Lines of population 1 that had significant reduction, were more numerous than in population 17, and FDK and DON reduction were greater.

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