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Selection for milling and baking quality in wheat (Triticum aestivum L.) head-rows could increase the efficiency of most soft winter wheat (SWW) breeding programs. We evaluated whole grain-wheat meal (WM) assays for their ability to select lines with acceptable SWW quality and high gluten strength in early-generations and estimated heritability of SWW quality and gluten strength. One hundred fourteen lines from a cross of strong and weak gluten parents was assessed over three location-years. Flour quality and gluten strength were measured using flour and WM measures. Correlations between WM assays on head-rows and flour-based assays conducted on replicated trials from two locations were significant (P < 0.05). Wheat meal sedimentation volume (WM-SED) was correlated with flour lactic acid solvent retention capacity (SRC; r = 0.37). Wheat meal sodium carbonate SRC (WM-SRC) was correlated with flour sucrose (r = 0.37), flour sodium carbonate (r = 0.46) and flour water (r = 0.47) SRC and negatively correlated with wire-cut cookie diameter (r = -0.33) and flour yield (r = -0.40). Soft winter wheat quality and gluten strength improved when selections were based on WM-SRC and WM-SED, respectively. Early-generation selection for SWW quality and gluten strength using WM tests should increase the frequency of SWW selections with desirable quality characteristics in replicated yield trials.

There has been increasing interest in developing soft white winter wheat (Triticum aestivum L.) cultivars for areas that have traditionally grown only soft red winter wheat. To develop white wheat segregates in a red wheat breeding program requires deliberate breeding decisions. The objectives of this study were to assess differences in agronomic, disease, and milling and baking quality traits between red and white progeny in 11 red x white crosses and to determine the optimal time and method for identifying white segregates from red x white crosses. Red and white progeny from the 11 populations were evaluated in replicated experiments at three locations in 2005-2006. White progeny produced significantly (p < 0.05) lower grain yields than red progeny in two of five environments studied. Deoxynivalenol level was significantly (p < 0.05) higher in white than in red progeny in the three environments in which it was measured. Flour yield, flour lactic acid solvent retention capacity, and softness equivalent were significantly (p < 0.05) lower for white progeny than for red progeny. To determine the optimal generation for selection of white lines, early-generation bulk selection was compared with single seed descent in three populations at two locations. Although there were significant (p < 0.05) differences between selection methods within populations, neither breeding method was consistently superior across the three populations. Simulated selection of superior white lines based on agronomic and milling and baking quality showed no significant differences between the selection methods.

Fusarium head blight (FHB), caused by Fusarium graminearum (Sehwabe), is an economically important disease of wheat (Triticum aestivum L.). After epidemics in the USA during the 1990s, a resistance-breeding effort was undertaken focusing initially on the transfer of Type II resistance from unadapted Chinese cultivars. The objective of this study was to determine the magnitude and heritability of resistance in populations derived from adapted parents. Three soft red winter (SRW) wheat populations of 40 families each were artificially inoculated with Fusarium graminearum under mist irrigation in 2003 and 2004 at Lexington and Princeton, KY. Traits measured included anthesis date, plant height, disease severity, Fusarium-damaged kernels (FDK) and deoxynivalenol (DON) concentration. Broad sense heritability (BSH) estimates were generated from entry means over the four environments. Heritability of severity was approximately 0.30 in all populations; heritability of FDK ranged from 0.16 to 0.20. In 2003, a selection intensity of 20% was imposed on all populations, and the eight lowest severity families were advanced and evaluated at Lexington and Princeton in 2004. Direct selection response, averaged over both locations, ranged from 1.9 to 4.1% reduction in severity. Correlated reduction in FDK ranged from 0.4 to 6.5%; there was also a correlated increase in plant height of 1.7 to 4.1 cm after one cyde of selection. Progress in FHB resistance breeding in the absence of major QTL is likely to be constrained by low heritability and genotype x environment (G x E) interaction.

Fusarium head blight (FHB) caused by Fusarium graminearum Schwabe causes losses in wheat (Triticum aestivum L.) seed quality and yield. Field studies were conducted in 2000 and 2001 to investigate F. graminearum seed infection (SI) and its relationship to seed germination and vigor and the production of the mycotoxin deoxynivalenol (DON). Seeds from four soft red winter wheat cultivars having different levels of Type II resistance to F. graminearum were harvested at frequent intervals during development and maturity. Low levels of SI occurred late in seed development in 2000, which resulted in high seed quality. In 2001, under heavy disease pressure, F. graminearum increased from 98% at maturity in both resistant and susceptible cultivars, resulting in unacceptable standard germination (SG) (, FUSARIUM HEAD BLIGHT reduces yield through floret sterility and poor seed filling, and severely reduces seed germination. Infection by F. graminearum lowers grain quality due to reductions in storage protein, [...]

Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe [teleomorph Gibberella zeae (Schwein.)], is a devastating disease that reduces yield, quality and economic value of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). The quantitative nature of resistance and tremendous expense of phenotypic screening indicate that the identification of resistant genotypes in breeding populations might be expedited by molecular markers. The markers must be polymorphic and informative across populations for them to be used by breeders. Worldwide, several groups are mapping genes for FHB resistance in wheat and barley and marker discovery is underway. Although these markers may be validated and made breeder-friendly by the laboratories that developed them, the urgency of the FHB situation in North America and worldwide requires efforts to accelerate this process. To take advantage of economies of scale and accelerate information sharing, we propose the establishment of a National Genotyping Center (NGC) for barley and wheat. The immediate objective of the NGC would be to identify and deploy breeder-friendly markers linked to FHB resistance quantitative trait loci (QTL). Over time, we propose that several regional genotyping centers will be established to correspond to regional and market class needs. The NGC would provide the regional centers with high throughput marker systems that would be used to genotype plants in breeding populations submitted by plant breeders. For the long term, we expect that the focus of the NGC will extend beyond FHB resistance, and that a key objective will be the development of new technologies to enhance plant breeding efforts., HEAD SCAB, or Fusarium head blight of wheat and barley is a significant disease with devastating economic consequences. Losses in the USA during the 1990s approached $3000 million (Windels, 2000). [...]

Genomic selection (GS) uses training population (TP) data to estimate the value of lines in a selection population. In breeding, the TP and selection population are often grown in different environments, which can cause low prediction accuracy when the correlation of genetic effects between the environments is low. Subsets of TP data may be more predictive than using all TP data. Our objectives were (i) to evaluate the effect of using subsets of TP data on GS accuracy between environments, and (ii) to assess the accuracy of models incorporating marker X environment interaction (MEI). Two wheat (Triticum aestivum L.) populations were phenotyped for 11 traits in independent environments and genotyped with single-nucleotide polymorphism markers. Within each population- trait combination, environments were clustered. Data from one cluster were used as the TP to predict the value of the same lines in the other cluster(s) of environments. Models were built using all TP data or subsets of markers selected for their effect and stability. The GS accuracy using all TP data was >0.25 for 9 of 11 traits. The between-environment accuracy was generally greatest using a subset of stable and significant markers; accuracy increased up to 48% relative to using all TP data. We also assessed accuracy using each population as the TP and the other as the selection population. Using subsets of TP data or the MEI models did not improve accuracy between populations. Using optimized subsets of markers within a population can improve GS accuracy by reducing noise in the prediction data set. [ABSTRACT FROM AUTHOR]

Genetic Analysis of Complex Traits Using SAS. Edited by ARNOLD M. SAXTON. SAS Institute, Cary, NC 27531. 2004. Paperback, 292 pp., $49.95. ISBN 1-59047-507-0. The title leads the reader to [...]

Fusarium head blight (FHB), caused by Fusarium graminearum, of wheat (Triticum aestivum L.) is a disease that periodically strikes the mid-Atlantic region of the United States. Breeding for resistant wheat varieties is an effective method of disease control. The objective of this study was to evaluate the effects of exotic FHB resistance quantitative trait loci (QTL), singly and in combination, on FHB resistance in soft red winter wheat (SRWW). Three FHB resistance QTL on chromosomes 3BS (Fhbl), 2D, and 5A were introgressed from nonadapted Chinese cultivar Ning7840 into the adapted SRWW cultivar McCormick. Eight near-isogenic lines (NIL) were developed by marker-assisted backcrossing. The NIL that combined 3BS and 2DL expressed the highest resistance and lowest deoxynivalenol (DON) content in four environments that included three field and one greenhouse studies. These results indicate that the combination of just two QTL (3BS and 2DL) would be useful to breed for improved FHB resistance in SRWW in the mid-Atlantic region. [ABSTRACT FROM AUTHOR]