Submitted to: Hereditas
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/15/2003
Publication Date: 8/15/2003
Citation: ZHOU,W.C., KOLB, F.L., BAI, G., DOMIER, L.L., YAO, J.B. 2003. Effect of individual sumai 3 chromosomes on resistance to scab spread within spikes and deoxynivalenol accumulation within kernels in wheat. Hereditas. Interpretive Summary: Scab is a destructive disease of wheat that is caused by a fungus named Fusarium graminearum. In addition to wheat, this fungus infects barley, oats, and rye, and causes stalk rot in corn. Wheat scab significantly reduces wheat grain yield and quality, resulting in billions of dollars in crop losses annually. The fungus also produces mycotoxins that limit the consumption of infected grain by humans and livestock. While it is sometimes possible to use fungicides to control the disease, the costs are often prohibitive. If scab resistant wheat varieties were developed, they could represent cost efficient and effective means of limiting losses caused by the disease. However, producing scab resistant wheat varieties by traditional breeding methods has been difficult because of the genetic complexity of scab resistance and the variability of environmental conditions that influence the development of the disease. The objectives of this study were to evaluate the role of different wheat chromosome segments in scab resistance and the production of mycotoxins. In this study, we identified the wheat chromosomal regions that significantly increased scab resistance and reduced the production of mycotoxins. The results of these studies will be of interest to researchers who are working to produce new scab resistant wheat varieties, which should reduce economic losses to wheat producers and reduce the levels of mycotoxin within harvested grain.
Technical Abstract: Two sets of substitution lines were developed by crossing individual monosomic lines of Chinese Spring (recipient) with scab (Fusarium graminearum) resistant cultivar Sumai 3 (donor) and then using the monosomics as the recurrent male parent for four backcrosses (without selting after each backcross). The disomic substitution lines were separated from selfed BC4F2 plants. Chromosome specific SSR markers were analyzed for polymorphism between Sumai 3 and Chinese Spring. Polymorphic markers were used to identify substitution lines for specific chromosomes. Based on the specific SSR markers, chromosome substitutions occurred in thirty-six lines, and six lines segregated alleles from the two parents or were homozygous for the allele from Chinese Spring. These substitution lines were used to evaluate Type II (spread within the head) and Type V (deoxynivalenol accumulation within kernels) scab resistance. The objective was to use the substitution lines to evaluate the effect of individual chromosomes of Sumai 3 on Type II and Type V scab resistance in the greenhouse. Significant differences in Type II scab resistance and deoxynivalenol (DON) levels among different Chinese Spring (Sumai 3) substitution lines were detected. Positive chromosome substitution effects on Type II scab resistance were found on chromosomes 2B, 3B, 6B, and 7A from Sumai 3. Chromosomes 3B and 7A also reduced DON accumulation within the kernels, while chromosomes 1B, 2D, and 4D from Sumai 3 increased DON concentration. Chromosome 7A from Sumai 3 had the largest effect on resistance to scab spread and DON accumulation. Additional research is in progress on the scab resistance conferred by chromosome 7A.