Fayaz Farzad, Aghaee Sarbarzeh Mostafa, Talebi Reza, Azadi Amin
Department of Agronomy & Plant Breeding, College of Agriculture, Islamic Azad University, Sanandaj Branch, Sanandaj, Iran.
Seed and Plant Improvement Institute, Agriculture Research Education and Extension Organization (AREEO), Karaj, Iran.
Biochem Genet. 2019 Feb;57(1):98-116. doi: 10.1007/s10528-018-9877-2. Epub 2018 Jul 26.
Durum wheat is grown mainly in rain-fed regions of Iran and the Mediterranean district under stressful conditions. Different environmental conditions and agricultural practices among ancient communities have led to the development of locally adapted genotypes known as landraces. Landraces are a valued source of genetic variety and show definite adaptation to local environmental conditions according to their home of origin. This study aimed to explore linkage disequilibrium (LD) analysis and the population structure and genetic diversity of Iranian durum wheat landraces. In this study, population structure and genome-wide LD were investigated in 129 durum landrace accessions using 1500 DArT markers. Both structure and discriminant analysis of principal components obviously subdivided the sample collection into seven distinct groups centered on key ancestors and regions of origin of the germplasm. Genetic diversity among the populations was primarily within population (68 vs. 32%). Mean LD values across the entire population sample decayed below r of 0.11 after 1 cM. LD decay of genomes A and B of Iranian durum wheat landrace is approximately 2-3 cM (r = 0.11) and approximately 0.5 cM (r = 0.12), respectively. Altogether, low LD decay, a high number of subpopulations, and the high existence of genetic diversity among and within populations were characteristics of the Iranian durum landrace collection. Hence, the existing genetic diversity within the population can be associated with the very long evolutionary history of plants in Iran. The populations we studied are hence presented as a valuable resource that can be used in basic and applied research in durum wheat breeding.
硬粒小麦主要种植在伊朗和地中海地区的雨养地区，生长环境较为恶劣。古代不同社区的环境条件和农业实践导致了适应当地环境的基因型即地方品种的发展。地方品种是遗传多样性的重要来源，根据其原产地表现出对当地环境条件的明确适应性。本研究旨在探索伊朗硬粒小麦地方品种的连锁不平衡（LD）分析、群体结构和遗传多样性。在本研究中，使用1500个DArT标记对129份硬粒小麦地方品种材料进行了群体结构和全基因组LD研究。主成分的结构分析和判别分析均明显将样本分为七个不同的组，这些组以种质的关键祖先和原产地为中心。群体间的遗传多样性主要存在于群体内部（68% 对32%）。整个群体样本的平均LD值在1厘摩后衰减至r值低于0.11。伊朗硬粒小麦地方品种A和B基因组的LD衰减分别约为2 - 3厘摩（r = 0.11）和约0.5厘摩（r = 0.12）。总体而言，低LD衰减、大量亚群体以及群体间和群体内遗传多样性的高度存在是伊朗硬粒小麦地方品种群体的特征。因此，群体内现有的遗传多样性可能与伊朗植物非常悠久的进化历史有关。我们研究的这些群体因此被视为一种宝贵的资源，可用于硬粒小麦育种的基础研究和应用研究。
