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Previous studies have shown that there is considerable population structure in cultivated barley (Hordeum vulgare Lo), with the strongest structure corresponding to differences in row number and growth habit. U.S. barley breeding programs include six-row and two-row types and winter and spring types in all combinations. To facilitate mapping of complex traits in breeding germplasm, 1816 barley lines from 10 U.S. breeding programs were scored with 1536 single nucleotide polymorphism (SNP) genotyping assays. The number of SNPs segregating within breeding programs varied from 854 to 1398. Model-based analysis of population structure showed the expected clustering by row type and growth habit; however, there was additional structure, some of which corresponded to the breeding programs. The model that fit the data best had seven populations: three two-row spring, two six-row spring, and two six-row winter. Average linkage disequilibrium (LD) within populations decayed over a distance of 20 to 30 cM, but some populations showed long-range LD suggestive of admixture. Genetic distance (allele-sharing) between populations varied from 0.11 (six-row spring vs. six-row spring) to 0.45 (two-row spring vs. six-row spring). Analyses of pairwise LD revealed that the phase of allelic associations was not well correlated between populations, particularly when their allele-sharing distance was >0.2. These results suggest that pooling divergent barley populations for purposes of association mapping may be inadvisable. doi: 10.2135/cropsci2009.04.0198

Control of Fusarium head blight (FHB), incited primarily by Fusarium graminearum Schwabe [telomorph Gibberella zea (Schwein)], has been a challenge for barley (Hordeum vulgare L.) producers in the upper midwestern United States for more than a decade. This disease manifests primarily in the form of food safety issues and quality discounts due to the presence of deoxynivalenol (DON), a mycotoxin produced by the pathogen. Cultural practices and fungicides only provide partial control; genetic resistance to FHB and DON accumulation may add to control of the disease. Field studies in North Dakota and China were conducted in FHB disease nurseries using 118 double-haploid lines from the cross C93-3230-24/'Foster'. Foster is susceptible to FHB, and C93-3230-24 is moderately resistant. The quantitative trait locus (QTL) analysis revealed five putative QTL for Type I FHB resistance; however, only the one in bins 7 and 8 of chromosome 2H was detected in more than 70% of the environments. In addition, QTL associated with late days to heading and maturity and tall plant height also were located in the same region. Three putative QTL for increased DON accumulation were detected; however, none were detected in more than three of the eight environments where data were collected. On the basis of these results, it is unlikely that C93-3230-24 has a novel QTL for FHB resistance different from those identified in other resistant accessions. However, C93-3230-24 is unique in that it provides QTL for improved FHB resistance but not reduced DON accumulation. This is an atypical response compared with other sources of FHB resistance and provides evidence that FHB resistance and DON accumulation are under separate genetic control.

Synthetic agrichemicals are used to minimize nutrient deficiencies and pests when developing and selecting modern small-grain cultivars. Some farmers believe that modern cultivars are not adapted to environments without these inputs, and old cultivars should be grown. Our objective was to determine the adaptability of spring wheat (Triticum aestivum L.) cultivars for production in certified organic environments. A single seed lot for 15 cultivars and two seed lots each for two others were used to establish 19 treatments evaluated for grain yield, protein content, kernel and volume weight, along with phenotypical growth traits on four certified organic fields in Minnesota and North Dakota in 2003 and 2004. The cultivars represented different development eras, but 11 were released since 1995. Interactions between environments and cultivars existed for the four grain parameters (P < 0.05), but some modern cultivars ranked high consistently for yield, protein content, and volume weight. For example, the modern cultivar Walworth produced an average of 500 kg [ha.sup.-1] more grain than the highest yielding cultivar developed before 1970. Seedling vigor and other phenotypical growth traits did not explain consistent yield differences between cultivars. These results suggest that modern spring wheat cultivars are adapted to certified organic environments. The phenotypical growth traits considered in this study are not suited as primary selection criterion for cultivars in certified organic environments.

Fusarium head blight (FHB), incited by Fusarium graminearum Schwabe, has caused devastating losses in both yield and quality of barley (Hordeum vulgate L.) produced in the northern Great Plains from 1993 to 2003. Thirty-five barley germplasm lines with partial resistance to FHB have been identified in exotic and unadapted germplasm lines. Little is known about their agronomic characteristics, malt quality, and reaction to other diseases as compared to adapted cultivars. This information is needed so barley breeders can make informed decisions when planning crosses involving the resistant germplasm lines. The objective of this study was to compare the agronomic performance, malt quality, and disease reaction of barley germplasm lines with partial FHB resistance to cultivars grown in the northern Great Plains. Agronomic and malting data were collected on the 35 germplasm lines and five check cultivars grown in five environments in North Dakota from 1998 to 2000. Data for FHB severity and deoxynivalenol (DON, a mycotoxin produced by F. graminearum) accumulation were obtained for the same 40 entries grown in FHB-epidemic nurseries in North Dakota from 1997 to 1999. Seedling responses to foliar pathogens common in the northern Great Plains were determined in the greenhouse during fall 1997. None of the FHB-resistant barley germplasm lines had acceptable malt quality for all traits. Kernel plumpness, grain protein concentration, and malt extract were the traits impacted most severely. The FHB-resistant barley germplasm lines headed significantly later than the adapted barley cultivars. Most FHB-resistant germplasm lines were susceptible to the common foliar diseases of the northern Great Plains. At least four cycles of breeding will probably be necessary to develop FHB-resistant germplasm lines acceptable to producers and the malting and brewing industry. Abbreviations: ASBC, American Society of Brewing Chemists; DON, deoxynivalenol; FHB, Fusarium head blight; RCBD, randomized complete block design., FUSARIUM HEAD BLIGHT has caused devastating losses in both the yield and quality of barley produced in the northern Great Plains from 1993 to 2003. From 1993 to 1997, total [...]

Tillage is declining in dryland wheat production systems. Our objectives were to determine if tillage x cultivar, seeding rate x cultivar, and tillage x seeding rate x cultivar interactions occurred for the yield components of hard red spring wheat (Triticum aestivum L. emend. Thell.) in a wheat-fallow monoculture. The cultivars AC Minto, Amidon, Bergen, Grandin, and Norm were seeded at 123, 247, and 371 kernels [m.sup.-2] in conventional-till (CONT), reduced-till (RT), and no-fill (NT) systems in a randomized complete block in a split-split plot arrangement during 1995-1998. Tillage x cultivar and tillage x seeding rate x cultivar interactions did not occur for any yield component (P > 0.05). A seeding rate x cultivar interaction occurred for both plant stand and tiller production, but the interaction resulted from a change in the magnitude of response and not in the ranking of cultivars to seeding rate adjustments for either yield component. Plant stand and the number of tillers per plant were unaffected by tillage systems, but the number of spike-bearing tillers increased from 411 [m.sup.-2] under CONT to 457 [m.sup.-2] under NT. Tillage systems did not affect the number of kernels per spike or kernel weight. More spike-bearing tillers per square meter occurred as the seeding rate increased, but there were fewer tillers per plant and a negative quadratic response in the number of kernels per spike. Results of this study indicate that the ranking of contrasting hard red spring wheat cultivars for yield components is unchanged by reductions in tillage in a wheat-fallow monoculture., CROP-FALLOW has been the dominant production system for hard red spring wheat (HRSW) in the Great Plains of North America. Intensified cropping systems are replacing crop fallow in this region [...]

Tillage is declining in wheat production systems in the Great Plains. Our objective was to determine if a tillage x cultivar interaction occurred for grain yield, protein concentration, kernel weight, and test weight for hard red spring wheat (Triticum aestivum L. emend. Thell.) in a wheat-fallow monoculture. We also wanted to know if seeding rate x cultivar and tillage x seeding rate x cultivar interactions occurred for these grain traits. The cultivars AC Minto, Amidon, Bergen, Grandin, and Norm were seeded at 123, 247, and 371 live kernels [m.sup.-2] in conventional-till (CONT), reduced-till (RT), and no-till (NT) systems in a randomized complete block with a split split-plot arrangement in southwestern North Dakota during 1995-1998. Tillage x cultivar, seeding rate x cultivar, and tillage x seeding rate x cultivar interactions did not occur for any grain trait (P > 0.05). Grain yield, protein concentration, kernel weight, and test weight were unaffected by tillage system. A positive quadratic response in grain yield occurred as the seeding rate was increased. Grain test weight increased from 577 to 586 g [m.sup.-3] as the seeding rate increased from 123 to 371 kernels [m.sup.-2], but grain protein concentration and kernel weight were unaffected. Grain yield ranged from 2473 to 3063 kg [ha.sup.-1], crude protein from 141 to 154 g [kg.sup.-1], kernel weight from 30 to 32 g [(1000 kernels).sup.-1], and test weight from 572 to 590 g [m.sup.-3] among the five cultivars. Results of this study suggest that cultivar recommendations under CONT can be extended to RT and NT systems in a wheat-fallow monoculture., TILLAGE is being reduced in dryland cropping systems in the Great Plains of North America. For example, RT systems were used on only 18% of total cropland in North Dakota [...]

Fusarium head blight (FHB), incited by Fusarium graminearum Schwabe [telomorph Gibberella zea (Schwein)], has caused devastating losses to yield and quality of barley (Hordeum vulgare L.) produced in the upper U.S. Midwest from 1993 to 2000. Design of an efficient breeding strategy for developing FHB resistant cultivars is dependent on knowing (i) the heritability of FHB resistance and accumulation of deoxynivalenol (DON), a mycotoxin contaminant produced by F. graminearum and (ii) the correlated response of other traits during selection for reduced FHB. We conducted field studies in FHB disease nurseries using [F.sub.4:5] and [F.sub.4:6] families from the cross between the FHB susceptible six-rowed cultivar Foster and the resistant two-rowed accession CIho 4196 to gain knowledge in the areas listed above. Heritability of FHB severity and DON accumulation was 0.65 and 0.46, respectively. A moderately strong positive association between FHB severity and DON accumulation was observed (r = 0.62). FHB severity and DON accumulation were negatively associated with plant height, days to heading, spike angle, and spike density. The selection differentials calculated between the top [F.sub.4:6] families selected for low FHB severity and the unselected [F.sub.4:5] families were moderately high for FHB severity, DON accumulation, and days to heading. Less than 14% of the selected lines had six-rowed spikes. No difference in plant height was observed between the selected and unselected families. Thus, development of FHB resistant lines with acceptable DON accumulation and days to heading is obtainable. However, because no lines were as short as Foster, development of FHB resistant plants with acceptable plant height from a cross using CIho 4196 as a parent will be difficult., NORTH DAKOTA is the leading state in barley production with 30.6% of the overall U.S. production (USDA, 2000). The area sown and harvested has been significantly reduced in the last [...]

Malt fermentability, along with malt extract, helps determine the amount of malt needed for beer production. While diastatic power (DP) was initially associated with fermentability, it was later demonstrated that variation in fermentability is poorly explained by DP alone. Several studies have suggested that β-amylase and its thermostability, as well as some malt modification parameters, can considerably improve fermentability estimations, especially with commercial malts. However, few experiments have measured variation in fermentability within barley breeding lines, where variation in quality parameters can be wider. The objective of this study was to determine the effect of standard and nonstandard malt quality parameters on the fermentability of 90 barley genotypes, grown at different locations and years in North Dakota, and to then select the best multi-linear regression equation for predicting this trait. Our results showed that, unlike the results of previous studies, β-amylase and its thermostability were not highly associated with fermentability. Rather, wort fermentable sugars, limit-dextrinase, free amino nitrogen, soluble protein, and α-amylase were found to be most closely associated with fermentability. Overall, the results of the current experiment further demonstrate that fermentability results are very population dependent, and that the development of a universal equation is unlikely. [ABSTRACT FROM AUTHOR]

Malting of rye and the use of rye malts presents several challenges to maltsters and brewers, like the lack of a hull, dense packing in steep, and high wort viscosity. While empirical evidence shows that rye genotypes differ in malting and brewing performance and flavor, there is little published information on the malting of rye or the malt quality attributes of rye genotypes. The objective was to evaluate laboratory micro-malting conditions that could be used in quality screening. Parameters included germination time, moisture and kernel size. Wort arabinoxylan and phenolic acid contents were determined in addition to standard malt quality parameters. In general, high extract and lower viscosity were achieved by malting for at least 4 days at 45%'48% moisture under the temperature of 16 °C. However, as some commercial maltsters indicated the difficulty of handling of germinating rye at the highest moisture levels, we recommend 5 days of germination at 45% moisture for the future evaluation of rye cultivars. [ABSTRACT FROM AUTHOR]

The sugarbeet root maggot,Tetanops myopaeformis(Röder), is a major North American pest of sugarbeet,Beta vulgarisL. Previous research suggests that moderateT. myopaeformiscontrol is possible with the entomopathogenMetarhizium anisopliae(Metch.) Sorok. We conducted a three-year (2002–2004) experiment to assess impacts of oat,Avena sativaL. and rye,Secale cerealeL., cover crops on persistence of corn grit-based granular or spray formulations ofM. anisopliaeisolate ATCC 62176 (i.e. MA 1200) applied at 8×1012viable conidia/ha in sugarbeet. More colony forming units (CFUs) were detected immediately after application [0 days after treatment (DAT)] in spray plots than granule-treated plots. However, 76–92% declines in CFUs per gram of soil occurred in spray plots within 30 DAT. Substantially (i.e. 83–560%) more rainfall occurred in June 2002 than during June of any other year. Subsequently, 71–670% increases in CFU concentrations occurred by 60 DAT inM. anisopliaegranule-treated plots with oat or rye cover crops that year. CFU density increases were higher in cover crops in 2002, but no significant cover crop effects were detected. Conidia persisted for up to 30 DAT inM. anisopliaespray plots and 60 DAT in granule-treated plots in 2002; however, no increases occurred in the years with less June rainfall. Trends suggest thatM. anisopliaeaqueous sprays result in greater conidia concentrations than granules at sugarbeet plant bases in June duringT. myopaeformisoviposition and larval establishment on host plants. Increases are possible when delivering conidia via granules, but high post-application rainfall could be necessary for conidia production. [ABSTRACT FROM AUTHOR]

Semi-dwarfing genes have been widely used in spring barley ( Hordeum vulgare L.) breeding programs in many parts of the world, but the success in developing barley cultivars with semi-dwarfing genes has been limited in North America. Exploiting new semi-dwarfing genes may help in solving this dilemma. A recombinant inbred line population was developed by crossing ZAU 7, a semi-dwarf cultivar from China, to ND16092, a tall breeding line from North Dakota. To identify quantitative trait loci (QTL) controlling plant height, a linkage map comprised of 111 molecular markers was constructed. Simple interval mapping was performed for each of the eight environments. A consistent QTL for plant height was found on chromosome 7HL. This QTL is not associated with maturity and rachis internode length. We suggest the provisional name Qph-7H for this QTL. Qph-7H from ZAU 7 reduced plant height to about 3/4 of normal; thus, Qph-7H is considered a semi-dwarfing gene. Other QTLs for plant height were found, but their expression was variable across the eight environments tested. [ABSTRACT FROM AUTHOR]

This project was initiated with the goal of investigating the malt quality of winter rye cultivars and hybrids grown in the United States in 2014 and 2015, but high levels of deoxynivalenol (DON) were subsequently found in many of the malt samples. DON levels in 75% of the investigated rye samples (n = 117) were actually below 1.0 mg/kg, as quantified by a gas chromatography combined with electron capture detector (GC-ECD). However, 83% of the samples had DON in excess of 1.0 mg/kg following malting, and the average DON level in malted rye was 10.6 mg/kg. In addition, relatively high levels of 3-acetate DON (3-ADON), 15-acetate DON (15-ADON), nivalenol (NIV), and DON-3-glucoside (D3G) were observed in some rye malts. Our results show that rye grain DON is likely a poor predicator of type B trichothecenes in malt in practice, because high levels of malt DON, 15-ADONm and D3G were produced, even when the rye samples with DON levels below 0.50 mg/kg were processed. Fusarium Tri5 DNA content in rye was highly associated with malt DON levels (r = 0.83) in a small subset of samples (n = 55). The impact of Fusarium infection on malt quality was demonstrated by the significant correlations between malt DON levels and wort viscosity, β-glucan content, wort color, wort p-coumaric acid content, and total phenolic content. Additional correlations of rye Fusarium Tri5 DNA contents with malt diastatic power (DP), wort free amino nitrogen (FAN) content, and arabinoxylan content were observed. [ABSTRACT FROM AUTHOR]