Tunisia is considered a secondary center of diversification of durum wheat and has a large number of abandoned old local landraces. An accurate investigation and characterization of the morphological and genetic features of these landraces would allow their rehabilitation and utilization in wheat breeding programs. Here, we investigated a diverse collection of 304 local accessions of durum wheat collected from five regions and three climate stages of central and southern Tunisia. Durum wheat accessions were morphologically characterized using 12 spike- and grain-related traits. A mean Shannon-Weaver index (H′) of 0.80 was obtained, indicating high level of polymorphism among accessions. Based on these traits, 11 local landraces including Mahmoudi, Azizi, Jneh Khotifa, Mekki, Biskri, Taganrog, Biada, Badri, Richi, Roussia and Souri were identified. Spike length (H′ = 0.98), spike shape (H′ = 0.86), grain size (H′ = 0.94), grain shape (H′ = 0.87) and grain color (H′ = 0.86) were the most polymorphic morphological traits. The genetic diversity of these accessions was assessed using 10 simple sequence repeat (SSR) markers, with a polymorphic information content (PIC) of 0.69. Levels of genetic diversity were generally high (I = 0.62; He = 0.35). In addition, population structure analysis revealed 11 genetic groups, which were significantly correlated with the morphological characterization. Analysis of molecular variance (AMOVA) showed high genetic variation within regions (81%) and within genetic groups (41%), reflecting a considerable amount of admixture between landraces. The moderate (19%) and high (59%) levels of genetic variation detected among regions and among genetic groups, respectively, highlighted the selection practices of farmers. Furthermore, Mahmoudi accessions showed significant variation in spike density between central Tunisia (compact spikes) and southern Tunisia (loose spikes with open glume), may indicate an adaptation to high temperature in the south. Overall, this study demonstrates the genetic richness of local durum wheat germplasm for better in situ and ex situ conservation and for the subsequent use of these accessions in wheat breeding programs.

中文翻译：

---

突尼斯硬粒小麦（Triticum turgidum var. durum）种质的形态特征和遗传多样性分析

突尼斯被认为是硬粒小麦多样化的次要中心，有大量废弃的当地老地方品种。对这些地方品种的形态和遗传特征进行准确的调查和表征，将使它们能够在小麦育种计划中得到修复和利用。在这里，我们调查了从突尼斯中部和南部的五个地区和三个气候阶段收集的 304 个当地硬粒小麦种质的多样化集合。使用 12 个穗和谷粒相关性状对硬粒小麦种质进行形态学表征。获得了 0.80 的平均 Shannon-Weaver 指数 (H')，表明种质之间存在高水平的多态性。基于这些特征，确定了 11 个当地地方品种，包括 Mahmoudi、Azizi、Jneh Khotifa、Mekki、Biskri、Taganrog、Biada、Badri、Richi、R​​oussia 和 Souri。穗长 (H' = 0.98)、穗形 (H' = 0.86)、晶粒尺寸 (H' = 0.94)、粒形 (H' = 0.87) 和粒色 (H' = 0.86) 是最具多态性的形态特征. 这些种质的遗传多样性使用 10 个简单序列重复 (SSR) 标记进行评估，多态信息含量 (PIC) 为 0.69。遗传多样性水平普遍较高（I = 0.62；He = 0.35）。此外，种群结构分析揭示了11个遗传组，它们与形态特征显着相关。分子变异分析 (AMOVA) 显示区域内 (81%) 和遗传组内 (41%) 内的遗传变异很高，反映了地方品种之间的大量混合。在区域和基因组之间检测到中等（19%）和高（59%）水平的遗传变异，分别突出农民的选择实践。此外，Mahmoudi 种质在突尼斯中部（紧凑的穗状花序）和突尼斯南部（具有开放颖片的松散穗状花序）之间显示出穗密度的显着差异，这可能表明对南方高温的适应。总体而言，这项研究证明了当地硬粒小麦种质的遗传丰富性，可以更好地进行原地和异地保护，并随后将这些种质用于小麦育种计划。