Stability and Adaptability Concepts of Bread Wheat (Triticum aestivum L.) in the Northwest of Tunisia

Introduction: Stability and adaptability of 25 bread wheat (Triticum aestivum L.) cultivars were evaluated for genotype × environment interaction (G × E) and yield stability across two environments over 2 years (2014 and 2015). Materials and methods: Five improved varieties (Haidra, Salammbô, Tahent, Utique, and Vagua) released in Tunisia and 20 introduced genotypes (V1–V20) have been tested under two contrasted environments during 2 years characterized by different precipitations in the northwest of Tunisia. Several statistical approaches were conducted to evaluate yield stability: (a) regression coefficient (bi), (b) deviation from regression (Sdi), (c) ecovalence (Wi), (d) Hühn stability (Sli), and (e) AMMI stability value. Results: A standard multifactor analysis of variance test showed that the main effects due to genotypes, locations, and the interaction (genotype × locations) were highly significant. The highly significant interactions indicate that genotypes need to be tested during several years and at different locations for selecting the most stable one. The results showed that all statistical analyses allowed classifying the 25 studied genotypes according to their grain yield level (low, medium, or high), their adaptability to different environments. Conclusion: Tahent variety was confirmed to be most valuable due to its high production level, stability and its adaptability to variable environments including unfavorable ones

Understanding the Effects of Genotype, Growing Year, and Breeding on Tunisian Durum Wheat Allergenicity. 1. the Baker's Asthma Case

Baker's asthma is a serious airway disease triggered by wheat protein CM3 α-amylase/trypsin inhibitor. The purpose of the present study was to investigate the impact of genotype and crop year on allergen CM3 α-amylase/trypsin inhibitor associated with baker's asthma. A historical series of Tunisian durum wheat (100 accessions), derived from three crop years, was used to compare the amount of CM3 from landraces to advanced cultivars. CM3 protein quantification was assessed after an enzymatic cleavage of the soluble protein extracts on a UPLC/ESI-MS system, using a marker peptide for its quantification. Combined data analysis of variance revealed an important effect of genotype, crop year, and their interaction. The CM3 allergenic proteins were found to significantly vary among studied genotypes, as confirmed by genetic variability, coefficient of variance, heritability, and genetic advance

Understanding the Effects of Genotype, Growing Year, and Breeding on Tunisian Durum Wheat Allergenicity. 2. The Celiac Disease Case

The aim of this study was to compare immunogenic and toxic gluten peptides related to celiac disease (CD). 100 accessions of genotypes selected during the 20th century in Tunisia were in vitro digested and then analyzed by UPLC/ESI-MS technique using an isotopically labeled internal standard. The first MANOVA confirmed a high variability in the content of immunogenic and toxic peptides reflecting high genetic diversity in the germplasm released during the past century in Tunisia, consistently with PCA and clustering analysis results. Our finding showed also important variability in CD epitopes due to growing season’s climate scenarios. Moreover, the second MANOVA revealed significant differences between abandoned and modern cultivars’ CD-related peptide amounts. Although we could not conclude that there was an augment of allergens in newly selected durum wheat lines compared to abandoned ones, we demonstrated that modern genotype peptides were less sensitive to climate variation, which is a useful indicator for wheat breeders

Insights into a century of breeding of durum wheat in Tunisia: The properties of flours and starches isolated from landraces, old and modern genotypes

The present work had a dual objective: to assess if the evolution of durum wheat from landraces to modern genotypes as function of breeding programs impacted proteins and starch fractions, as well as starch properties. Flours and starches isolated from Tunisian durum wheat landraces, old and modern lines were thoroughly characterized for their compositional, morphological, and gel properties. Statistical results showed significant (p ≤ 0.05) differences among the studied set. Protein and starch fractions assessment revealed that modern genotypes had the highest total starch and albumin contents, old genotypes had the highest amylose and glutenin contents, and landraces had the highest protein and gliadin contents. Starch properties screening allowed several findings: no significant (p > 0.05) differences were found among starch granules morphology, significant (p ≤ 0.05) differences were recorded in terms of technological properties, and old genotypes had the highest starch gel hardness. Overall, these results indicated that the influence of genotype on flour and starch properties was more relevant than breeding history

Phenolic profile and antioxidant capacity of landraces, old and modern Tunisian durum wheat

In the last decades, the consumption of whole wheat has increased because consumers’ awareness has increased toward healthy food. However, breeders’ focus was always attributed to the major components of wheat, but less attention was paid to micronutrients. The aim of this study was to provide new insights on the influence of breeding on total polyphenol content (TPC), phenolic profile, and total antioxidant capacity (TAC) using a set of Tunisian durum wheat landraces, old and modern varieties. Ultra-liquid chromatography multi-stage mass spectrometry (UHPLC–MSn) allowed the identification of eight phenolic acids, which were found in the bound form, while only p-coumaric acid was found in the free form. A significant genotype effect on the TPC (bound, free and total), TAC, and phenolic acid profile was observed. Regarding breeding effect, TPC concentrations were in the order modern > landraces > old. Principal component analysis (PCA) confirmed that the phenolic profile of the studied varieties was mainly conditioned by their genotypic characteristics, and no trend was observed as a function of breeding history. Likewise, clustering analysis highlighted an important genetic diversity, suggesting that the modern variety ‘‘Om Rabia’’ possesses the most interesting phenolic profile. These findings might be useful to breed genetically different and phenolic-rich new varieties