Authors:M. Camerini, T. Amoriello, G. Aureli, A. Belocchi, M. Fornara, S. Melloni, and F. Quaranta
Deoxynivalenol (DON) contamination was investigated of Italian durum wheat from organic agriculture. A number of 661 samples from 13 genotypes were collected within the national organic durum wheat network variety trials during the six-year period between 2007–2012 in five different growing areas across Italy (Northern Italy, Marches, Central Apennines, West-Central Italy, Apulia). Mean temperatures and total rainfalls in April, May and June were collected nearby the study sites. Average DON contamination value along the whole study period was 67 μg/kg, and DON was detected only in 36% of the samples. Noteworthy, 95% of the analyzed grain revealed a DON contamination lower than 334 μg/kg. Maximum allowed DON level for unprocessed durum wheat set by European Union (1750 μg/kg) was exceeded only in four samples (0.6%). The highest mean DON values were detected in Northern Italy (175 μg/kg) and Marches (131 μg/kg). The same was for the percentage of positive samples (80% and 58%, respectively). Lower mean values and percentages of contaminated samples were found in West-Central Italy (22 μg/kg and 29%, respectively), Apennines (3 μg/kg and 8%, respectively) and Apulia (2 μg/kg and 7%, respectively). Statistical analysis (Generalized Linear Model, GLZ) was carried out to highlight the effect of factors like cultivation year, growing area and genotype. It revealed a huge effect of year, growing areas and their interaction, while the effect of genotype resulted significantly but quite less than the other main factors. The effect of the year could be explained by climatic data, which suggested an influence of rainfall and temperature at heading on both DON concentration values and percentage of contaminated samples. Results of this study put in evidence a low DON contamination in Italian organic durum wheat.
Authors:A. Etminan, A. Pour-Aboughadareh, R. Mohammadi, A. Noori, and A. Ahmadi-Rad
Progress in plant molecular tools has been resulted in the development of gene-targeted and functional marker systems. CAAT box region is a different pattern of nucleotides with a consensus sequence, GGCCAATCT, which situated upstream of the start codon of eukaryote genes and plays an important role during transcription. In the present study, several CAAT box-derived polymorphism (CBDP) primers were used for fingerprinting in mini-core collection of durum wheat (including internationally developed breeding lines and Iranian landraces). Twelve selected primers amplified 98 loci, of which all were polymorphic. The average values of the polymorphism information content (PIC) and resolving power (Rp) were 0.31 and 9.16, respectively, indicating a high level of variability among studied genotypes. Analysis of molecular variance (AMOVA) indicated that 92% of the total variation resided among populations. The values of the percentage polymorphic bands (PPL), the observed (Na) and effective (Ne) number of alleles, Nei’s gene diversity (He) and Shannon’s information index (I) for Iranian landraces were higher than the breeding lines. The Fandendrogram obtained by cluster analysis grouped all individuals into three main clusters. Our results showed a remarkable level of genetic diversity among studied durum wheat, especially among Iranian landraces, which can be interest for future breeding programs. More importantly, the present study also revealed that CBDP technique was efficient and powerful tool to assess genetic diversity in wheat germplasm. Hence, this technique could be employed individually or in combination with other molecular markers to evaluate genetic diversity and relations among different species.
Waterlogging is one of the limiting factors influencing durum wheat (Triticum durum L.) production. In this paper we investigated the impact of seven waterlogging durations of 4, 8, 12, 16, 20, 40, and 60 days, imposed at 3-leaf and 4-leaf growth stages, on grain yield, grain yield components, straw and root dry weight and nitrogen concentration of grain, straw, and roots of two varieties of durum wheat. Grain yield of both varieties showed a significant reduction only when waterlogging was prolonged to more than 20 days, and 40-d and 60-d waterlogging reduced grain yield by 19% and 30%. Waterlogging depressed grain yield preventing many culms from producing spikes. It slowed down spikelet formation, consequently reducing the number of spikelets per spike, and reduced floret formation per spikelet, thus reducing the number of kernels per spike.
Authors:S.M. Pirseyedi, A. Kumar, F. Ghavami, J.B. Hegstad, M. Mergoum, M. Mazaheri, S.F. Kianian, and E.M. Elias
Fusarium head blight (FHB) damage in durum wheat (Triticum turgidum L. var. durum Desf., turgidum) inflicted massive economic losses worldwide. Meanwhile, FHB resistant durum wheat germplasm is extremely limited. ‘Tunisian108’ is a newly identified tetraploid wheat with FHB resistance. However, genomic regions in ‘Tunisian108’ that significantly associated with FHB resistance are yet unclear. Therefore, a population of 171 backcross inbred lines (BC1F7) derived from a cross between ‘Tunisian108’ and a susceptible durum cultivar ‘Ben’ was characterized. Fusarium graminearum (R010, R1267, and R1322) was point inoculated (greenhouse) or spawn inoculated (field) in 2010 and 2011. Disease severity, Fusarium-damaged kernel (FDK) and mycotoxins were measured. Analysis of variance showed significant genotype and genotype by environment effect on all traits. Approximately 8% of the lines in field and 25% of the lines in greenhouse were more resistance than Tunisian108. A framework linkage map of 267 DArt plus 62 SSR markers was developed representing 239 unique loci and covering a total distance of 1887.6 cM. Composite interval mapping revealed nine QTL for FHB severity, four QTL for DON, and four QTL for FDK on seven chromosomes. Two novel QTL, Qfhb.ndsu-3BL and Qfhb.ndsu-2B, were identified for disease severity, explaining 11 and 6% of the phenotypic variation, respectively. Also, a QTL with large effect on severity and a QTL with negative effect on FDK on chromosome 5A were identified. Importantly, a novel region on chromosome 2B was identified with multiple FHB resistance. Validation on these QTL would facilitate the durum wheat resistance breeding.
Authors:D. Tinak Ekom, S. Udupa, F. Gaboun, M. Benchekroun, M. Ennaji, and D. Iraqi
The use of mature embryos as explants to initiate cultures is a best alternative to save time and costs, especially for producing somatic embryos for genetic transformation of durum wheat. However, plantlets regeneration from cultures derived from matured embryos is usually low. In this study, we tested matured embryos as explants from eight Moroccan durum wheat varieties (‘Irden’, ‘Marzak’, ‘Kyperounda’, ‘Isly’, ‘Amria’, ‘Karim’, ‘Marouane’ and ‘Tomouh’) to define suitable culture media for obtaining high frequencies of somatic embryogenesis and in vitro plantlets regeneration. For this purpose, we tested five induction and maintenance media (M1 to M5) based on MS media (macro and oligo-elements) which differed with respect to concentrations of plant hormones (2,4-D and BA), vitamins, sucrose, maltose, L-asparagine, and solidifying agents. All tested media induced embryogenic callus for the varieties and regenerate plantlets. However, a significant effect of variety, medium and variety × medium interaction were observed for callus induction and regeneration. Average callus growth as measured by relative fresh weight growth rate (RFWGR) across different media was the highest for ‘Amria’ (7215.4%) and the lowest for ‘Tomouh’ (2088.2%). M1 (2 mg/L 2,4-D) and M5 (3 mg/L 2,4-D) media gave highest RFWGR(6892.1% and 6332%, respectively) and M3 (1 mg/L 2,4-D) was the lowest (3708.8%), across different varieties. However, the embryogenic callus from M3 media regenerated the highest percentage of plantlet, upon transfer to regeneration medium, for most of the varieties. For the varieties ‘Marouane’, ‘Kyperounda’, ‘Marzak’, ‘Karim’, and ‘Tomouh’, the favourable medium was M3, whereas, for ‘Isly’, ‘Irden’ and ‘Amria’, both M2 (2.5 mg/L BA and 2.5 mg/L 2,4-D) and M3 were the favourable media for embryogenic callus induction. In this study, for the first time, favourable media for induction and regeneration from mature embryo of Moroccan durum wheat varieties were identified. These media will be used for callus induction and genetic transformation.
Drought is the major cause of durum wheat yield losses in the Mediterranean and many other regions where the crop is not normally irrigated. Over three years (2010–13), 24 durum wheat genotypes representing diverse genetic materials were tested under drought and irrigated conditions. The main objectives were to assess the degree of genotypic variation for drought tolerance, characterize genotypic differences in response to drought, and identify sources of germplasm with greater drought tolerance than old and new cultivars. The percent reduction in average grain yield under drought conditions as compared to irrigated conditions was maximum (69%) during 2012–13, followed by 2010–2011 (33%) and 2011–2012 (15%). The average yields of genotypes under drought conditions differed significantly, which ranged from 1174 (correspond to old variety) to 2086 kg/ha (correspond to breeding line G2). The maximin-minimax approach, yield tolerance index (YTI) and three-dimensional (3-D) plot were used to classify genotypes for drought tolerance and yield productivity. Based on the results, two genotypes were identified as resistant and high yielding (G3 and G20), and eight genotypes (G2, G22, G8, G11, G15, G1, G9 and G5) were found to be high yielding and tolerant to drought conditions. Among the methods, the maximin–minimax approach appears to be more useful in identifying high yielding and drought tolerant genotypes as it seeks to minimize percentage yield loss while maximizing yield potential. In conclusion, considerable variability in yield and drought tolerance was observed for the durum wheat genotypes, which could be exploited at improving drought tolerance in durum wheat breeding program.
Authors:Laura Ercoli, Alessandro Masoni, Marco Mariotti, and Iduna Arduini
Soil gravel content affects many soil physical properties, i.e. bulk density, porosity, water infiltration and storage, as well as crop yield. Little is known regarding the influence of soil gravel content on grain yield of durum wheat (
Desf.). In this paper the accumulation of dry matter during the vegetative and reproductive periods and the contribution of pre-anthesis assimilates to grain yield have been evaluated in two durum wheat varieties grown on soils with 0, 10, 20, and 30% gravel content. The two varieties showed similar behaviour and more soil gravel decreased plant biomass both at anthesis and at maturity. Soil gravel content greatly reduced grain yield and dry weight of all plant parts both at anthesis and maturity. Post-anthesis dry matter accumulation was 16% lower in plants grown on 30% gravel soil and dry matter remobilization was 53% lower, compared to plants grown in gravel-free soil. The differences in growth rate were attributed to the restriction of the volume of soil available for root growth.
Authors:N. Di Benedetto, C. Fares, V. Menga, M. Laus, D. Pastore, and Z. Flagella
Epidemiological studies associated consumption of whole-durum wheat products with reduced incidence of chronic diseases, diabetes and cancer. These health benefits have been mainly attributed to antioxidant activity (AA) due to the unique phytochemical content of wheat. Milling, extrusion and drying process can influence the activity of these beneficial compounds. In order to have a deep insight into the changes of nutritional value from raw material to pasta, the aim of this study was: i) to compare the AA of hydrophilic and lipophilic extracts of five durum wheat genotypes along the pasta chain; ii) to evaluate the changes in antioxidant properties of whole meal after processing in semolina and pasta. To this aim TEAC (Trolox Equivalent Antioxidant Capacity) assay based on ABTS•+ [2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) scavenging activity was used due to its high reproducibility and simplicity.Low genotype variability was observed for both hydrophilic and lipophilic extracts. Milling process caused a significant decrease in AA due to the removal of the outside layers of the kernel. This decrease was more marked for lipophilic extracts due to the different distribution of hydrophilic and lipophilic antioxidants along the kernel. Pasta making process while determining a further decrease in AA of lipophilic extracts caused a slight increase in AA of hydrophilic extracts compared to semolina. This might be due to melanoidins formed during Maillard reaction.Only for lipophilic extracts a predictive evaluation of semolina and pasta ABTS•+ scavenging activity was possible by testing raw material.