Abstract
Tan spot (TS), caused by the fugus Pyrenophora tritici-repentis (Ptr), has gained significant importance in the last few years, thereby representing a threat to wheat production in all major wheat-growing regions, including Tunisia. In this context, we evaluated a Mediterranean collection of 549 durum wheat accessions under field conditions for resistance to Ptr over two cropping seasons in Jendouba (Tunisia), a hot spot for Ptr. The relative disease severities showed significant phenotypic variation from resistance to susceptibility. The correlation between disease scores over the two trials was significant, as 50% of the accessions maintained good levels of resistance (resistant–moderately resistant). Seedling and adult-stage reactions were significantly correlated. The ANOVA analysis revealed that the genotype term is highly significant at the adult stage, thus emphasizing the high genetic variability of the tested accessions. Reaction-type comparison among and between countries revealed a high diversity of TS resistance. Plant height (PH) was negatively correlated to disease scores, indicating that PH might either have a significant effect on TS severity or that it can be a potential disease escape trait. The evaluation of this collection allowed for the identification of potential diverse resistance sources to Ptr that can be incorporated in breeding programs.
Highlights
The Mediterranean region is known as a major secondary center of durum wheat (Triticum turgidum), the domestication of which occurred in the region 12,000 years ago [1]
This study aims to evaluate a collection of Mediterranean durum wheat accessions originating from Algeria, France, Italy, Portugal and Spain for resistance to P. tritici-repentis under field conditions at the seedling and adult growth stages over two cropping seasons
The identification of typical conidia of Pyrenophora tritici-repentis (Ptr) from collected leaf samples confirmed the infection with tan spot (Figure S3), and several obtained isolates have been published in Laribi et al [24,25]
Summary
The Mediterranean region is known as a major secondary center of durum wheat (Triticum turgidum), the domestication of which occurred in the region 12,000 years ago [1]. The genetic evolution of durum wheat in the Mediterranean region, as well as natural and human selection, led to the establishment of Landraces, with key quality traits including agronomic, quality characteristics, and adaptation to the region’s contrasting environment [2,3,4,5,6]. Durum wheat is still grown in the Mediterranean basin and North African countries (Algeria, Morocco, Tunisia, and Libya) mainly for its culinary final products, such as semolina, pasta, couscous, frike, and bourghul. North Africa produces 18.7 million tons (MT) of durum wheat, of which 1.5 MT is in Tunisia [7].
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