|Wiersma, J V - UNIVERSITY OF MINNESOTA|
|Peters, E L - UNIVERSITY OF MINNESOTA|
|Hanson, M A - UNIVERSITY OF MINNESOTA|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 1, 1996
Publication Date: N/A
Interpretive Summary: Fusarium head blight, or scab, as it is more commonly known, is a devastating disease in wheat. It greatly reduces yield and quality of the grain, but more importantly produces a toxin, called vomitoxin. This vomitoxin can cause sickness in humans and animals. Although this study was not intended to measure the resistance of spring wheat varieties to the edisease of scab, the disease was present in both 1993 and 1994. This natural disease epidemic allowed us to measure the varietal effect of partial resistance present in the 16 wheat varieties evaluated. Four wheat varieties had lower disease in both years at most planting dates used. These varieties, Marshall, Nordic, Butte 86, and Grandin, had lower numbers of heads infected and less severity of spread of the disease in the heads. Probably because of the partial resistance displayed by these varieties, they were higher yielding and had higher test weight. No wheat is known to ohave immunity to scab. Thus, this information is important to wheat breeders searching for more resistance in better agronomic varieties. Higher resistance has been found in certain Chinese and Japanese wheats, but these are not adapted to our growing conditions and must be used only as parents to try to transfer the resistance from them to the better varieties identified above.
Technical Abstract: Fusarium head blight (FHB), caused primarily by Fusarium graminearum Schwabe, is an important but sporadic disease throughout major spring wheat (Triticum aestivum L.) production areas in Canada and the US. In the absence of genetic immunity, identification of cultivars that have partial resistance to natural FHB infections may provide management alternatives that can be used to reduce the risk of uncertain environments. Our objectives were to (1) examine the effects of years, planting dates, cultivars, and their interactions on FHB measures and agronomic traits; and (2) characterize cultivar responses across a range of environments. Eight planting dates and 16 hard red spring wheat cultivars were studied during 1993 and 1994 at Crookston, MN. Normal and above normal rain during June, July, and August provided moist conditions during anthesis of most cultivars across several planting dates each year. FHB incidence (FHBI) and severity (FHBS) varied markedly with planting date (FHBI range: 24.3 t 41.9%; FHBS range: 28.6 to 41.8%), anthesis date (FBHI range: 19.7 to 60.3%; FHBS range: 28.6 to 41.9%), year (FHBI range: 30.0 to 42.5%; FHBS range: 30.7 to 43.5%), and cultivar (FHBI range: 22.5 to 54.9%; FHBS range: 33.5 to 39.3%). Cultivars that achieved higher than average grain yield and test weight over all environments did so because they performed well in severe FHB environments. Cultivar mean grain yield (r=-0.75, P=0.01) and test weight (r=-0.93, p=0.01) were inversely correlated with cultivar mean FHB incidence. Butte 86,' Grandin,' Marshall,' and Nordic' generally had lower mean FHB incidence and severity and were less responsive to environments favorable for disease than other cultivars. These cultivars also had higher grain yield and test weight than most other cultivars.