Characterization of the Protein and Carbohydrate Related Quality Traits of a Large Set of Spelt Wheat Genotypes.

Spelt wheat (Triticum aestivum subsp. spelta L.) is an underexploited hexaploid wheat species that has become an increasingly fashionable raw material of bakery products in the last decades, partly because of its ability to grow under organic agricultural conditions and partly because of the growing number of people following the trend of having a healthy diet. However, due to its difficult threshing, most research on spelt seed is based on a very limited number of genotypes. Therefore, we determined the physical, compositional, and breadmaking quality traits of 90 spelt genotypes in order to highlight the variation of these properties and to identify possible genetic resources for spelt improvement. The thousand kernel weight of the spelt genotypes ranged between 23.2 and 49.7 g, the protein content between 12.1% and 22.2%, the gluten index between 0.7 and 98.8, the dough stability between 0.0 and 19.6 min, and the starch damage between 6.3 and 19.4 UCD value. The average values showed that spelt has higher protein and gluten contents but weaker dough strength and stability than common bread wheat. The starch pasting temperature was also higher in spelt, but the starch damage was lower, resulting in lower water absorption. Some genebank accessions (MVGB142, 145, 353, and 525) and internationally available cultivars (Bohemia, Bodensonne, Black-Bearded, and White-Beardless) were identified as good genetic resources for improving the breadmaking-quality traits of spelt.

Variation in the Content and Composition of Tocols in a Wheat Population.

Wheat is a well-known source of B vitamins but also contains significant amounts of vitamin E and related tocols, which have a number of positive health benefits. However, there are no reports on increasing the tocol content of wheat. A prerequisite for increasing the tocol content is the identification of variation in its amount within wheat and related cereals. We therefore determined the tocol content and composition in the grain of 230 recombinant inbred lines (RILs) of a diverse biparental wheat population (Mv Toborzó/Tommi), showing variation in the total content from 13.69 to 45.18 µg/g d.m. The total content also showed transgressive segregation in the population. The effect of the genotype on the variance components of tocols was studied, and the broad-sense heritability was calculated to be 0.71. The lines were also grouped based on their tocol content and analyzed for their chemical composition and breadmaking quality. The high heritability value and the wide variation found in the total amount indicate that increasing the content of tocols is a possible breeding strategy.

Abiotic Stress Response of Near-Isogenic Spring Durum Wheat Lines under Different Sowing Densities.

A detailed study was made of changes in the plant development, morphology, physiology and yield biology of near-isogenic lines of spring durum wheat sown in the field with different plant densities in two consecutive years (2013-2014). An analysis was made of the drought tolerance of isogenic lines selected for yield QTLs (QYld.idw-2B and QYld.idw-3B), and the presence of QTL effects was examined in spring sowings. Comparisons were made of the traits of the isogenic pairs QYld.idw-3B++ and QYld.idw-3B-- both within and between the pairs. Changes in the polyamine content, antioxidant enzyme activity, chlorophyll content of the flag leaf and the normalized difference vegetation index (NDVI) of the plot were monitored in response to drought stress, and the relationship between these components and the yield was analyzed. In the case of moderate stress, differences between the NIL++ and NIL-- pairs appeared in the early dough stage, indicating that the QYld.idw-3B++ QTL region was able to maintain photosynthetic activity for a longer period, resulting in greater grain number and grain weight at the end of the growing period. The chlorophyll content of the flag leaf in phenophases Z77 and Z83 was significantly correlated with the grain number and grain weight of the main spike. The grain yield was greatly influenced by the treatment, while the genotype had a significant effect on the thousand-kernel weight and on the grain number and grain weight of the main spike. When the lines were compared in the non-irrigated treatment, significantly more grains and significantly higher grain weight were observed in the main spike in NIL++ lines, confirming the theory that the higher yields of the QYld.idw-3B++ lines when sown in spring and exposed to drought stress could be attributed to the positive effect of the "Kofa" QTL on chromosome 3B.

A novel approach to the characterization of old wheat (Triticum aestivum L.) varieties by complex rheological analysis.

BACKGROUND: Lines of the internationally recognized old Hungarian Bánkúti 1201 variety are important genetic resources for breeding programmes. Their protein composition and gluten dependent technological traits have been comprehensively studied, however, little information is available about their carbohydrate dependent viscous properties. The aim of this work was to obtain comprehensive rheological characterization of all sublines of Bánkúti 1201 maintained at Martonvásár and to investigate their variability if the carbohydrate dependent viscous behaviour was also included in the analyses. RESULTS: The majority of the lines reflected the famously good mixing quality of Bánkúti, however, much higher diversity of pasting behaviour was detected. Cluster analysis of the Mixolab data was performed resulting in four sample groups. Since several lines of similar mixing properties had significantly different pasting characteristics, it was assumed that classification was mainly based on the viscous properties. From each cluster two to three representative samples were selected for wider examination using conventional testing methods. These results also supported the higher variability of pasting behaviour of the lines, which can be critical for end product quality. The members of the second cluster can be highlighted due to their waxy wheat like behaviour. CONCLUSIONS: Possible reasons for the great variability of pasting behaviour could be the compositional and structural differences of starch and other carbohydrates (e.g. arabinoxylans). Complex rheological characterization and study of molecular background can provide information about important traits from the point of view of technology and product development, which are unknown in the case of old wheat varieties and landraces. © 2020 Society of Chemical Industry.

Stability analysis of wheat lines with increased level of arabinoxylan.

Plant breeders have long sought to develop lines that combine outstanding performance with high and stable quality in different environments. The high-arabinoxylan (AX) Chinese variety Yumai-34 was crossed with three Central European wheat varieties (Lupus, Mv-Mambo, Ukrainka) and 31 selected high-AX lines were compared for physical (hectolitre weight, thousand grain weight, flour yield), compositional (protein content, gluten content, pentosan) and processing quality traits (gluten index, Zeleny sedimentation, Farinograph parameters) in a three-year experiment (2013-2015) in the F7-F9 generations. The stability and heritability of different traits, including the relative effects of the genotype (G) and environment (E), were determined focusing on grain composition. The contents of total and water-soluble pentosans were significantly affected by G, E and G × E interactions, but the heritability of total (TOT)-pentosan was significantly lower (0.341) than that of water-extractable (WE)-pentosan (0.825). The main component of the pentosans, the amount and composition (arabinose:xylose ratio) of the arabinoxylan (AX), was primarily determined by the environment and, accordingly, the broader heritability of these parameters were 0.516 and 0.772. However, genotype significantly affected the amount of water-soluble arabinoxylan and its composition and thus the heritability of these traits was also significant (0.840 and 0.721). The genotypes exhibiting higher stability of content of TOT-pentosan also showed more stable contents of WE-pentosan. There was a positive correlation between the stability of contents of WE-pentosan and WE-AX, while the stability of the WE-AX content and AX composition were also strongly correlated. Water absorption was strongly genetically determined with a heritability of 0.829 with the genotype determining 38.67% of the total variance. Many lines were grouped in the GGE biplot, indicating that they did not significantly differ stability.

Drought stress affects the protein and dietary fiber content of wholemeal wheat flour in wheat/Aegilops addition lines.

Wild relatives of wheat, such as Aegilops spp. are potential sources of genes conferring tolerance to drought stress. As drought stress affects seed composition, the main goal of the present study was to determine the effects of drought stress on the content and composition of the grain storage protein (gliadin (Gli), glutenin (Glu), unextractable polymeric proteins (UPP%) and dietary fiber (arabinoxylan, ß-glucan) components of hexaploid bread wheat (T. aestivum) lines containing added chromosomes from Ae. biuncialis or Ae. geniculata. Both Aegilops parents have higher contents of protein and ß-glucan and higher proportions of water-soluble arabinoxylans (determined as pentosans) than wheat when grown under both well-watered and drought stress conditions. In general, drought stress resulted in increased contents of protein and total pentosans in the addition lines, while the ß-glucan content decreased in many of the addition lines. The differences found between the wheat/Aegilops addition lines and wheat parents under well-watered conditions were also manifested under drought stress conditions: Namely, elevated ß-glucan content was found in addition lines containing chromosomes 5Ug, 7Ug and 7Mb, while chromosomes 1Ub and 1Mg affected the proportion of polymeric proteins (determined as Glu/Gli and UPP%, respectively) under both well-watered and drought stress conditions. Furthermore, the addition of chromosome 6Mg decreased the WE-pentosan content under both conditions. The grain composition of the Aegilops accessions was more stable under drought stress than that of wheat, and wheat lines with the added Aegilops chromosomes 2Mg and 5Mg also had more stable grain protein and pentosan contents. The negative effects of drought stress on both the physical and compositional properties of wheat were also reduced by the addition of these. These results suggest that the stability of the grain composition could be improved under drought stress conditions by the intraspecific hybridization of wheat with its wild relatives.

Addition of Aegilops U and M Chromosomes Affects Protein and Dietary Fiber Content of Wholemeal Wheat Flour.

Cereal grain fiber is an important health-promoting component in the human diet. One option to improve dietary fiber content and composition in wheat is to introduce genes from its wild relatives Aegilops biuncialis and Aegilops geniculata. This study showed that the addition of chromosomes 2Ug, 4Ug, 5Ug, 7Ug, 2Mg, 5Mg, and 7Mg of Ae. geniculata and 3Ub, 2Mb, 3Mb, and 7Mb of Ae. biuncialis into bread wheat increased the seed protein content. Chromosomes 1Ug and 1Mg increased the proportion of polymeric glutenin proteins, while the addition of chromosomes 1Ub and 6Ub led to its decrease. Both Aegilops species had higher proportions of ß-glucan compared to arabinoxylan (AX) than wheat lines, and elevated ß-glucan content was also observed in wheat chromosome addition lines 5U, 7U, and 7M. The AX content in wheat was increased by the addition of chromosomes 5Ug, 7Ug, and 1Ub while water-soluble AX was increased by the addition of chromosomes 5U, 5M, and 7M, and to a lesser extent by chromosomes 3, 4, 6Ug, and 2Mb. Chromosomes 5Ug and 7Mb also affected the structure of wheat AX, as shown by the pattern of oligosaccharides released by digestion with endoxylanase. These results will help to map genomic regions responsible for edible fiber content in Aegilops and will contribute to the efficient transfer of wild alleles in introgression breeding programs to obtain wheat varieties with improved health benefits. Key Message: Addition of Aegilops U- and M-genome chromosomes 5 and 7 improves seed protein and fiber content and composition in wheat.

Powdery Mildew Resistance in Wheat Cultivar Mv Hombár is Conferred by a New Gene, PmHo.

A new powdery mildew resistance gene designated as PmHo was identified in 'Mv Hombár' winter wheat, bred in Martonvásár, Hungary. It has exhibited a high level of resistance over the last two decades. Genetic mapping of recombinant inbred lines derived from the cross 'Ukrainka'/Mv Hombár located this gene on chromosome 2AL. The segregation ratio and consistent effect in all environments indicated that PmHo is a major dominant powdery mildew resistance gene. The race-specific nature of resistance in Mv Hombár was shown by the emergence of a single virulent pathotype designated as 51-Ho. This pathotype was, to some extent, able to infect Mv Hombár, developing visible symptoms with sporulating colonies. Microscopic studies revealed that, in incompatible interactions, posthaustorial hypersensitivity reaction was the most prevalent but not exclusive plant defense response in Mv Hombár, and fungal growth was mostly arrested during haustorium formation or in the early stages of colony development. The delayed fungal development of the virulent pathotype 51-Ho may be explained by additional effects of other loci that were also involved in the powdery mildew resistance of Mv Hombár.

Allele frequencies in the VRN-A1, VRN-B1 and VRN-D1 vernalization response and PPD-B1 and PPD-D1 photoperiod sensitivity genes, and their effects on heading in a diverse set of wheat cultivars (Triticum aestivum L.).

Heading of cereals is determined by complex genetic and environmental factors in which genes responsible for vernalization and photoperiod sensitivity play a decisive role. Our aim was to use diagnostic molecular markers to determine the main allele types in VRN-A1, VRN-B1, VRN-D1, PPD-B1 and PPD-D1 in a worldwide wheat collection of 683 genotypes and to investigate the effect of these alleles on heading in the field. The dominant VRN-A1, VRN-B1 and VRN-D1 alleles were present at a low frequency. The PPD-D1a photoperiod-insensitive allele was carried by 57 % of the cultivars and was most frequent in Asian and European cultivars. The PPD-B1 photoperiod-insensitive allele was carried by 22 % of the genotypes from Asia, America and Europe. Nine versions of the PPD-B1-insensitive allele were identified based on gene copy number and intercopy structure. The allele compositions in PPD-D1, PPD-B1 and VRN-D1 significantly influenced heading and together explained 37.5 % of the phenotypic variance. The role of gene model increased to 39.1 % when PPD-B1 intercopy structure was taken into account instead of overall PPD-B1 type (sensitive vs. insensitive). As a single component, PPD-D1 had the most important role (28.0 % of the phenotypic variance), followed by PPD-B1 (12.3 % for PPD-B1_overall, and 15.1 % for PPD-B1_intercopy) and VRN-D1 (2.2 %). Significant gene interactions were identified between the marker alleles within PPD-B1 and between VRN-D1 and the two PPD1 genes. The earliest heading genotypes were those with the photoperiod-insensitive allele in PPD-D1 and PPD-B1, and with the spring allele for VRN-D1 and the winter alleles for VRN-A1 and VRN-B1. This combination could only be detected in genotypes from Southern Europe and Asia. Late-heading genotypes had the sensitivity alleles for both PPD1 genes, regardless of the allelic composition of the VRN1 genes. There was a 10-day difference in heading between the earliest and latest groups under field conditions.

Effect of heat and drought stress on the structure and composition of arabinoxylan and ß-glucan in wheat grain.

The effects of heat (H), drought (D) and H+D (from 12th day after heading for 15 days) on the dietary fiber content and composition (arabinoxylan (AX) and ß-glucan) of three winter wheat varieties (Plainsman V, Mv Magma and Fatima 2) were determined. Results showed that H and D stress decreased the TKW, the ß-glucan contents of the seeds and the quantity of the DP3+DP4 units, while the protein and AX contents increased. The highest amounts of AX and proteins were in the H+D stressed samples with heat stress also increasing the water extractability (WE) of the AX. However, while the content of AX content was generally increased by all stresses, drought stress had negative effect on the AX content of the drought tolerant Plainsman V. Fatima 2 behaved similarly to Plainsman V as regards to its drought tolerance, but was very sensitive to heat stress, while Mv Magma was the most resistant to heat stress.

Transgenic approach to improve wheat (Triticum aestivum L.) nutritional quality.

An amaranth (Amaranthus hypochondriacus) albumin gene, encoding the 35-kDa AmA1 protein of the seed, with a high content of essential amino acids, was used in the biolistic transformation of bread wheat (Triticum aestivum L.) variety Cadenza. The transformation cassette carried the ama1 gene under the control of a powerful wheat endosperm-specific promoter (1Bx17 HMW-GS). Southern-blot analysis of T(1) lines confirmed the integration of the foreign gene, while RT-PCR and Western-blot analyses of the samples confirmed the transcription and translation of the transgene. The effects of the extra albumin protein on the properties of flour, produced from bulked T(2) seeds, were calculated using total protein and essential amino acid content analysis, polymeric/monomeric protein and HMW/LMW glutenin subunit ratio measurements. The results indicated that not only can essential amino acid content be increased, but some parameters associated with functional quality may also be improved because of the expression of the AmA1 protein.

Design and management of field trials of transgenic cereals.

The development of gene transformation systems has allowed the introgression of alien genes into plant genomes, thus providing a mechanism for broadening the genetic resources available to plant breeders. The design and the management of field trials vary according to the purpose for which transgenic cereals are developed. Breeders study the phenotypic and genotypic stability of transgenic plants, monitor the increase in homozygosity of transgenic genotypes under field conditions, and develop backcross generations to transfer the introduced genes into secondary transgenic cereal genotypes. For practical purposes, they may also multiply seed of the transgenic lines to produce sufficient amounts of grain for the detailed analysis of trait(s) of interest, to determine the field performance of transgenic lines, and to compare them with the non-transformed parental genotypes. Prior to variety registration, the Distinctness, Uniformity and Stability (DUS) tests and Value for Cultivation and Use (VCU) experiments are carried out in field trials. Field testing includes specific requirements for transgenic cereals to assess potential environmental risks. The capacity of the pollen to survive, establish and disseminate in the field test environment, the potential for gene transfer, the effects of products expressed by the introduced sequences and phenotypic and genotypic instability that might cause deleterious effects must all be specifically monitored, as required by EU Directives 2003/701/EC (1) on the release of genetically modified higher plants in the environment.

Composition and end-use quality of 150 wheat lines selected for the HEALTHGRAIN Diversity Screen.

The HEALTHGRAIN program is focused on developing new healthy food products based on wholegrains of wheat and other cereals, by combining enhanced nutritional quality with good agronomic performance and processing quality. A sample set comprising 130 winter and 20 spring wheat varieties was therefore selected to identify the range of variation in a number of phytochemical and dietary fiber components. These lines were also analyzed for their technological properties (protein and gluten contents, Zeleny sedimentation, bran yield, kernel hardness, etc.), using samples grown on adjacent sites for two successive seasons (2004-2005, 2005-2006). On the basis of the frequency distribution and principal component analysis it was concluded that significant variation for technological quality traits is present in the 150 wheat lines and that it is possible to combine enhanced nutritional quality with good agronomic performance and processing properties.