Effects of genetic and agronomic factors on grain composition in oats

The effects of genetic variability and agronomic practises on the chemical compounds of the grain were evaluated in a set of oat cultivars (16 naked and four husked) grown in different experiments in the years 2004–2008. In the first experiment, carried out for two years, β-glucan and Total Dietary Fibre (TDF) from eight oat cultivars, grown under three different levels of nitrogen fertilization and two seed doses, were considered. The second experiment, involving 12 cultivars for two years, explored the variation of β-glucan solubility and further characterized six cultivars for the content of TDF and arabinoxylans. In both experiments, genotype was found to exert the largest effect on the grain composition; nitrogen levels and seed doses had positive significant effects on protein and β-glucan contents, but did not affect fibre content. Among the naked cultivars, Irina, Abel, Luna, Hendon and Expression showed a good ability to accumulate the examined grain compounds. However, in general, the highest contents of protein and β-glucan were found in the groats of husked cultivars, suggesting that specific breeding programs are a crucial step to identify the suitable naked oat genotypes to produce foods of high nutritional value

Genome wide association mapping for arabinoxylan content in a collection of tetraploid wheats

BACKGROUND: Arabinoxylans (AXs) are major components of plant cell walls in bread wheat and are important in bread-making and starch extraction. Furthermore, arabinoxylans are components of soluble dietary fibre that has potential health-promoting effects in human nutrition. Despite their high value for human health, few studies have been carried out on the genetics of AX content in durum wheat. RESULTS: The genetic variability of AX content was investigated in a set of 104 tetraploid wheat genotypes and regions attributable to AX content were identified through a genome wide association study (GWAS). The amount of arabinoxylan, expressed as percentage (w/w) of the dry weight of the kernel, ranged from 1.8% to 5.5% with a mean value of 4.0%. The GWAS revealed a total of 37 significant marker-trait associations (MTA), identifying 19 quantitative trait loci (QTL) associated with AX content. The highest number of MTAs was identified on chromosome 5A (seven), where three QTL regions were associated with AX content, while the lowest number of MTAs was detected on chromosomes 2B and 4B, where only one MTA identified a single locus. Conservation of synteny between SNP marker sequences and the annotated genes and proteins in Brachypodium distachyon, Oryza sativa and Sorghum bicolor allowed the identification of nine QTL coincident with candidate genes. These included a glycosyl hydrolase GH35, which encodes Gal7 and a glucosyltransferase GT31 on chromosome 1A; a cluster of GT1 genes on chromosome 2B that includes TaUGT1 and cisZog1; a glycosyl hydrolase that encodes a CelC gene on chromosome 3A; Ugt12887 and TaUGT1genes on chromosome 5A; a (1,3)-β-D-glucan synthase (Gsl12 gene) and a glucosyl hydrolase (Cel8 gene) on chromosome 7A. CONCLUSIONS: This study identifies significant MTAs for the AX content in the grain of tetraploid wheat genotypes. We propose that these may be used for molecular breeding of durum wheat varieties with higher soluble fibre content.Ilaria Marcotuli, Kelly Houston, Robbie Waugh, Geoffrey B. Fincher, Rachel A. Burton, Antonio Blanco, Agata Gadalet

Effects of genotype and environment on phenolic acids content and total antioxidant capacity in durum wheat

In cereals, phenolic acid (PA) content and total antioxidant capacity (TAC) may have a wide range of variability, probably because of several factors influencing the occurrence of grain antioxidants, which include genotype, environment, and their possible interactions. However, only a few studies have investigated the influence of these factors on durum wheat. In the present study, we investigated the impact of the genetic and environmental factors on the profile and content of PAs occurring as soluble free, soluble conjugated, and insoluble bound compounds, as well as on the TAC level, in three genotypes of durum wheat grown in three different Italian agroclimatic areas during two crop years. The results show that genotype, environment, and crop year have highly significant effects on TAC levels and on PA contents. In particular, TAC and free PAs are most influenced by year, whereas conjugated and bound PAs are most influenced by environment 7 year and genotype, respectively. Therefore, it is evidenced that genetic and environmental factors affect the antioxidant activity and the content of the three forms of PAs in durum wheat to different extents

How do conventional and organic management affect the healthy potential of durum wheat grain and semolina pasta traits?

The effect of cropping system (conventional vs. organic) and soil tillage (conventional vs. reduced tillage) on the health potential of durum wheat grain as well as on semolina and pasta quality traits was investigated in a long-term field experiment. Total antioxidant capacity, total arabinoxylans, alkylresorcinols, yellow pigments and total phenolics, which were assessed in kernels, revealed differences between the two cultivation systems only in 2011, whereas in the 2010 rainy season, cropping management did not influence these compounds. Proteins and W index were higher in the conventional system, except for the exceptionally rainy years. In contrast, the quality of cooked spaghetti was comparable in both management systems. Soil tillage differently affected bioactive compounds but had no impact on semolina and pasta quality. Overall, climatic conditions was the major factor affecting the quality of durum wheat. Our results indicate that an organic system does not represent a constraint to obtaining durum wheat grain with healthy potential relative to conventional wheat

Variation of total antioxidant activity and of phenolic acid, total phenolics and yellow coloured pigments in durum wheat (Triticum turgidum L. var. durum) as a function of genotype, crop year and growing area

This paper reports the results of a study carried out to investigate the effects of genetic and environmental factors on the total antioxidant activity and on the occurrence of certain antioxidant compounds in durum wheat. The content of phenolic acids (PAs) and of total phenolics (TPC), both occurring as soluble free, soluble conjugated and insoluble bound forms, as well as the yellow coloured pigments (YCP) and the level of total antioxidant capacity (TAC) were determined in ten durum wheat genotypes grown in the same experimental field over three consecutive crop years. Three of the investigated genotypes were also grown in other two Italian cultivation areas over the same period. Crop year, genotype, growing area and their interactions significantly affected the variables under study. The content of PAs and TPC was mostly affected by environment, whereas YCP content and TAC level were principally influenced by genetic factors

Use of bran fractions and debranned kernels for the development of pasta with high nutritional and healthy potential

The quality of pasta produced with debranning products (bran fractions, BF, and debranned kernels, DK) of durum wheat was investigated by evaluating their total antioxidant capacity, occurrence of nutritional and bioactive compounds, and sensory properties. Two pasta samples, produced with BF-enriched semolina (BF pasta) or only with micronized DK (DK pasta), respectively, were compared with pasta made with traditional semolina (control pasta). BF pasta and DK pasta displayed significantly higher content of bioactive compounds, such as phenolic compounds and dietary fibre, than control pasta, to a different extent for the diverse compounds. The present study indicates that the debranning process allows to produce pasta with a high content of healthy compounds and minimal effects on sensory properties, using only the natural endowment of durum wheat. This approach is suitable to produce cereal-based foods with the potential nutritional and health benefits of partially refined cereals and limitation of their main drawbacks

From seed to cooked pasta : influence of traditional and non-conventional transformation processes on total antioxidant capacity and phenolic acid content

The aim of this work was to compare the traditional with a non-conventional (i.e. kernel micronisation) durum wheat milling process by monitoring the content of bound, conjugated and free phenolic acids (PAs) and the level of the total antioxidant capacity (TAC) occurring in the durum wheat pasta production chain, from seed to cooked pasta. The traditional transformation processes negatively influenced TAC and PA content (40% and 89% decrease from seed to cooked pasta, respectively), mainly during the milling process (25% and 84% decrease of TAC and PA, respectively), which has been related to the removal of external layers of kernels. Conversely, the micronisation applied on durum wheat kernels allowed to obtain whole-wheat pasta that preserved the seed endowment of antioxidant compounds even in cooked pasta. These results indicate the micronisation as a valuable approach to produce pasta with improved nutritional value and potential health-promoting effects compared to the traditional pasta