Agropyron ISSR Dataset

The investigation utilized 37 ISSR primers, resulting in the detection of 956 loci within the A. elongatum genome and 705 loci within the A. cristatum genome. The findings revealed a high level of polymorphism, with 97% of loci in A. elongatum and 84% of loci in A. cristatum exhibiting variability. Notably, the primer (AC)8GCT emerged as a promising candidate for evaluating genetic diversity due to its ability to amplify numerous loci in both species. Using both the UPGMA algorithm and Bayesian analysis, the examined Agropyron accessions were categorized into two subgroups based on their respective species. The Q values associated with these subgroups suggested that certain accessions, namely \"G16,\" \"G19,\" \"G20,\" \"G21,\" \"G22,\" \"G23,\" \"G24,\" and \"G25,\" displayed potential admixture genomes. An analysis of molecular variance (AMOVA) underscored the significance of within-species variability, which accounted for 69% of the overall diversity, compared to between-species variability at 31%. Various genetic diversity parameters, including Na, Ne, I, He, and the number of private loci, were found to be higher in A. elongatum when compared to A. cristatum. Furthermore, Jaccard similarity coefficients ranged from 0.33 to 0.66 in A. cristatum and from 0.25 to 0.7 in A. elongatum, indicating the extent of genetic relatedness among these species. Intriguingly, the study identified two and three heterotic groups in A. cristatum and A. elongatum, respectively, which could be harnessed in the development of synthetic varieties to exploit heterosis. The results also indicated that a small proportion of ISSR loci pairs (5.2% in A. elongatum and 0.5% in A. cristatum) exhibited significant levels of linkage disequilibrium (LD) (P≤0.05), suggesting the potential utility of LD-based association mapping in Agropyron species. In conclusion, this research sheds light on the genetic diversity of Agropyron species and provides valuable insights into their potential applications in soil protection and forage production, as well as the prospects for enhancing genetic variability and heterosis in these species.

本研究采用37对简单序列重复区间扩增多态性（Inter-Simple Sequence Repeat，ISSR）引物，在长穗冰草（A. elongatum）基因组中检测到956个基因座（locus，复数形式loci），在冰草（A. cristatum）基因组中检测到705个基因座。研究结果显示二者均具有较高的多态性：长穗冰草（A. elongatum）的多态性基因座占比达97%，冰草（A. cristatum）为84%。值得注意的是，引物(AC)8GCT可在两个物种中扩增出大量基因座，是评估遗传多样性的优良候选引物。采用非加权组平均法（Unweighted Pair Group Method with Arithmetic Mean，UPGMA）与贝叶斯分析（Bayesian analysis），供试冰草属（Agropyron）种质可按物种划分为两个亚群。上述亚群对应的群体结构Q值显示，编号为G16、G19、G20、G21、G22、G23、G24及G25的部分种质存在潜在的混合基因组。分子方差分析（Analysis of Molecular Variance，AMOVA）结果表明，种内变异占总遗传多样性的69%，种间变异占31%，种内遗传变异的贡献更为显著。多项遗传多样性参数，包括观测等位基因数（number of observed alleles, Na）、有效等位基因数（effective number of alleles, Ne）、Shannon信息指数（Shannon's information index, I）、期望杂合度（expected heterozygosity, He）以及私有基因座数量，在长穗冰草（A. elongatum）中均高于冰草（A. cristatum）。此外，冰草（A. cristatum）的Jaccard相似系数取值范围为0.33~0.66，长穗冰草（A. elongatum）为0.25~0.7，该结果反映了供试材料间的遗传关联程度。值得注意的是，本研究分别在冰草（A. cristatum）与长穗冰草（A. elongatum）中鉴定出2个与3个杂种优势群，可用于合成品种培育以利用杂种优势。研究同时发现，仅少量ISSR基因座对存在显著连锁不平衡（linkage disequilibrium，LD）（P≤0.05）：长穗冰草（A. elongatum）占比5.2%，冰草（A. cristatum）占比0.5%，这表明基于连锁不平衡的关联作图技术在冰草属（Agropyron）物种中具有应用潜力。综上，本研究阐明了冰草属（Agropyron）物种的遗传多样性特征，为其在水土保持与牧草生产中的应用提供了重要参考，同时也为该类物种的遗传变异改良与杂种优势利用开辟了良好前景。