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Title: INHERITANCE OF RESISTANCE TO FUSARIUM GRAMINEARUM IN WHEAT

Author
item Bai, Guihua
item SHANER, GREGORY - PURDUE UNIV, W LAFAYETTE
item OHM, HERBERT - PURDUE UNIV, W LAFAYETTE

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/17/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Wheat scab, also know as Fusarium Head Blight (FHB), is a destructive disease of wheat. It not only significantly reduces grain yield and quality, but infected grain also contains toxins that are toxic to humans and livestock. The best way to control the disease is to develop more resistant wheat cultivars through plant breeding. All cultivars of wheat are susceptible to FHB, but some have limited resistance. To aid the plant breeding process, a better understanding of the genetic mechanism of resistance to FHB is needed. In this work, we tested progeny of crosses between partially resistant and susceptible varieties of wheat for scab spread, a type of FHB resistance, in a controlled greenhouse environment. Results indicate that one well known cultivar Ning 7840 has one gene with a major effect on disease resistance and two genes with minor effects. The genes identified seem to work additively. This indicates that it might be possible to improve FHB resistance through traditional plant breeding by accumulating additive resistance genes from different partially resistant cultivars.

Technical Abstract: To study the inheritance of resistance in wheat to Fusarium graminearum, six resistant cultivars from China were crossed to two susceptible cultivars. The parents and their progenies were evaluated in the greenhouse for resistance to spread of scab within a spike. A central floret was inoculated by injecting a droplet of inoculum at the time of anthesis. Inoculated plants were kept in a moist chamber for three subsequent nights. The proportion of scabbed spikelets was recorded six times from 3 days to 21 days after inoculation, and the area under the disease progress curve (AUDPC) was calculated from these proportions. One to three genes, depending on cultivar, conditioned resistance to scab as reflected by AUDPC. A simple additive-dominance effect model fit segregation data for eight of the eleven crosses. Dominance and epistatic effects were significant in a few crosses. These effects increased resistance in some crosses but decreased resistance in the others. However, relative to additive effects, dominant and epistatic effects accounted for only a small portion of genetic effects in the populations evaluated. The importance of additive effects means that it should be possible to accumulate different genes to enhance resistance to scab in wheat.