Mapping QTL conferring speckled snow mold resistance in winter wheat (Triticum aestivum L.).

Speckled snow mold caused by Typhula ishikariensis is one of the most devastating diseases of winter wheat in Hokkaido, Japan and parts of the Pacific Northwest region of USA. Münstertaler is a winter wheat landrace from Switzerland that has very high resistance to snow mold and superior freezing tolerance. Quantitative trait loci (QTL) for resistance to speckled snow mold were identified in a doubled haploid population derived from a cross between Münstertaler and susceptible variety Ibis, both under field conditions and controlled environment tests. Composite interval mapping analysis revealed a major QTL on chromosome 5D from Münstertaler, and on chromosome 6B from Ibis. Flanking microsatellite marker cfd 29 for the QTL on chromosome 5D was about 5 cM distant from vernalization requirement gene Vrn-D1, suggesting that the QTL on chromosome 5D is located on a cold-stress-related gene cluster along with Vrn-D1 and freezing tolerance gene Fr-D1. The QTL on chromosome 6B from Ibis was located on the centromere region flanking QTn.mst-6B, which is reported to increase plant tiller number.

Mapping of a major QTL associated with protein content on chromosome 2B in hard red winter wheat (Triticum aestivum L.).

A quantitative trait locus (QTL) controlling wheat grain protein content (GPC) and flour protein content (FPC) was identified using doubled haploid (DH) lines developed from a cross between the hard red winter wheat variety 'Yumechikara' with a high protein content used for bread making, and the soft red winter wheat 'Kitahonami' with a low protein content used for Japanese white salted noodles. A single major QTL, QGpc.2B-yume, was identified on the short arm of wheat chromosome 2B for both the GPC and FPC over 3 years of testing. QGpc.2B-yume was mapped on the flanking region of microsatellite marker Xgpw4382. The DH lines grouped by the haplotype of the closest flanking microsatellite marker Xgpw4382 showed differences of 1.0% and 1.1% in mean GPC and FPC, respectively. Yield-component-related traits were not affected by the haplotype of QGpc.2B-yume, and major North American hard red winter wheat varieties showed the high-protein haplotype. Unlike Gpc-B1 derived from tetraploid wheat, QGpc.2B-yume has no negative effects on yield-component-related traits and should be useful for wheat breeding to increase GPC and FPC.

Mapping a QTL conferring resistance to Fusarium head blight on chromosome 1B in winter wheat (Triticum aestivum L.).

Fusarium head blight (FHB) is one of the most devastating diseases of wheat (Triticum aestivum L.), and the development of cultivars with FHB resistance is the most effective way to control the disease. Yumechikara is a Japanese hard red winter wheat cultivar that shows moderate resistance to FHB with superior bread-making quality. To identify quantitative trait loci (QTLs) for FHB resistance in Yumechikara, we evaluated doubled haploid lines derived from a cross between Yumechikara and a moderate susceptible cultivar, Kitahonami, for FHB resistance in a 5-year field trial, and we analyzed polymorphic molecular markers between the parents. Our analysis of these markers identified two FHB-resistance QTLs, one from Yumechikara and one from Kitahonami. The QTL from Yumechikara, which explained 36.4% of the phenotypic variation, was mapped on the distal region of chromosome 1BS, which is closely linked to the low-molecular-weight glutenin subunit gene Glu-B3 and the glume color gene Rg-B1. The other QTL (from Kitahonami) was mapped on chromosome 3BS, which explained 11.2% of the phenotypic variation. The close linkage between the FHB-resistance QTL on 1BS, Glu-B3 and Rg-B1 brings an additional value of simultaneous screening for both quality and FHB resistance using the glume color.

Dough properties and bread-making quality-related characteristics of Yumechikara near-isogenic wheat lines carrying different Glu-B3 alleles.

We investigated the relationships of three allelic variations in Glu-B3 (ab, g, and h) with dough properties and bread-making quality-related characteristics using near-isogenic lines (NILs) of 'Yumechikara' that commonly carry Glu-A1a, Glu-B1b, Glu-D1d, Glu-A3f, Glu-B3ab and Glu-D3a. Measurement of peak time (PT) in a 2-g mixograph indicated that Glu-B3g was the most effective for a strong dough property, followed by Glu-B3ab, with Glu-B3h being the least effective. The results of measurement of mixing time during bread-making were similar to those for PTs, i.e., the lines carrying Glu-B3g showed the longest mixing time, followed by those of Glu-B3ab, and those of Glu-B3h showed the shortest mixing time. Since two parameters of bread-making quality, loaf volume (LV) and specific loaf volume (SLV), were affected by flour protein contents in all groups of the Glu-B3 genotype, we compared the effects of the three Glu-B3 alleles on those parameters using analysis of covariance (ANCOVA) to remove the effect of protein content. The results indicated that the Glu-B3h group showed the largest SLV, followed by the Glu-B3ab group, and the Glu-B3g group showed the smallest SLV. These results suggest that the introduction of Glu-B3h into 'Yumechikara' makes it possible to breed varieties with good bread-making quality-related characteristics.

Evaluation of fresh pasta-making properties of extra-strong common wheat (Triticum aestivum L.).

The relationship between characterictics of flour of common wheat varieties and fresh pasta-making qualitites was examined, and the fresh pasta-making properties of extra-strong varieties that have extra-strong dough were evaluated. There was a positive correlation between mixing time (PT) and hardness of boiled pasta, indicating that the hardness of boiled pasta was affected by dough properties. Boiled pasta made from extra-strong varieties, Yumechikara, Hokkai 262 and Hokkai 259, was harder than that from other varieties and commercial flour. There was a negative correlation between flour protein content and brightness of boiled pasta. The colors of boiled pasta made from Yumechikara and Hokkai 262 grown under the condition of standard manuring culture were superior to those of boiled pasta made from other varieties. Discoloration of boiled pasta made from Yumechikara grown under the condition of heavy manuring culture was caused by increase of flour protein content. On the other hand, discoloration of boiled pasta made from Hokkai 262 grown under the condition of heavy manuring culture was less than that of boiled pasta made from Yumechikara. These results indicate that pasta made from extra-strong wheat varieties has good hardness and that Hokkai 262 has extraordinary fresh pasta-making properties.

Deoxynivalenol Distribution in Flour and Bran of Spring Wheat Lines with Different Levels of Fusarium Head Blight Resistance.

The level of the fungal toxin deoxynivalenol (DON) in milled flour and its partitioning between flour and bran of 15 spring wheat (Triticum aestivum) lines with different levels of Fusarium head blight (FHB; mainly caused by Fusarium graminearum) resistance was investigated in Hokkaido, Japan between 2004 and 2007. The DON levels in flour (DONf) and bran (DONb) showed positive linear relationships with DON levels in whole kernels (DONk) (R2 = 0.94, n = 60, P ≤ 0.01 and R2 = 0.93, n = 60, P ≤ 0.01, respectively). Results indicated that the DON partitioning ratio between flour and bran is primarily related to the level of DONk, and the DON level was approximately doubled in DONb and halved in DONf for any level of DONk. Only one pattern of DON partitioning supported the conventional strategy to select FHB-resistant lines.

Influence of Cold-Hardening and Soil Matric Potential on Resistance to Speckled Snow Mold in Wheat.

The influence of soil matric potential, cold-hardening temperature, and duration on resistance to speckled snow mold caused by Typhula ishikariensis in wheat was investigated. Six winter wheat lines were subjected to cold-hardening temperatures of 2 or 4°C for 1, 2, 3, or 4 weeks with soil matric potential of -0.1 or -0.01 MPa. Plants were inoculated with T. ishikariensis after cold-hardening, incubated at 10°C for 25 days in the dark, and then evaluated for regrowth. Overall recovery from snow mold was least when plants were hardened at 2°C for 1 week at -0.01 MPa and greatest when hardened at 4°C for 4 weeks at -0.1 MPa. Survival of plants following snow mold was greater when plants were cold-hardened at 4 than at 2°C and at -0.1 than -0.01 MPa soil matric potential. The greatest difference in survival among lines and correlation with field observations occurred when plants were hardened at 4°C at -0.1 MPa matric potential for 3 weeks. Understanding the influence of temperature and soil matric potential during cold-hardening on speckled snow mold resistance will be useful to breeding programs developing snow-mold-resistant cultivars under controlled environment conditions.

Wheat cultivar-specific proteins in grain revealed by 2-DE and their application to cultivar identification of flour.

Wheat flour proteins were studied to identify the cultivar-specific proteins and use them to identify cultivars in flours. Proteins extracted from flours of Japanese wheat (cultivars Hokushin, Horoshirikomugi, Kitanokaori and Kachikei 33) and Canadian wheat (Canada Western Red Spring Wheat No. 1; 1CW) were analyzed by 2-DE with IEF gels over three pH ranges: pH 4-7, pH 5-8, and pH 6-11. This system enabled detection of more than 1600 protein spots. We recognized that among 50 protein spots showing cultivar-dependent qualitative changes, 25 proteins were wheat cultivar specific. These 50 protein spots were analyzed by N-terminal Edman degradation microsequencing and MALDI-TOF-MS; 21 protein spots were storage proteins, such as gliadin and low-molecular mass glutenin subunit. Five protein spots were identified as dehydroascorbate reductase (Triticum aestivum), triticin precursor (T. aestivum), alpha-amylase inhibitor (Oryza sativa), DNA-binding with one finger (Dof) zinc family protein (O. sativa), and nonphototropic hypocotyl 1 (NPH1) protein (Avena sativa). The other protein spots appeared to be hypothetical proteins (O. sativa or Arabidopsis thaliana) or functional unknown proteins. These specific proteins can be used as markers to identify wheat cultivars in blended flour composed of two or three flours.