Ledesma Alejandro, Ribeiro Fernando Augusto Sales, Uberti Alison, Edwards Jode, Hearne Sarah, Frei Ursula, Lübberstedt Thomas
Department of Agronomy, Iowa State University, Ames, IA, United States.
USDA-ARS, Corn Insects and Crop Genetics Research Unit, Ames, IA, United States.
Front Plant Sci. 2023 Jul 27;14:1226072. doi: 10.3389/fpls.2023.1226072. eCollection 2023.
Molecular characterization of a given set of maize germplasm could be useful for understanding the use of the assembled germplasm for further improvement in a breeding program, such as analyzing genetic diversity, selecting a parental line, assigning heterotic groups, creating a core set of germplasm and/or performing association analysis for traits of interest. In this study, we used single nucleotide polymorphism (SNP) markers to assess the genetic variability in a set of doubled haploid (DH) lines derived from the unselected Iowa Stiff Stalk Synthetic (BSSS) maize population, denoted as C0 (BSSS(R)C0), the seventeenth cycle of reciprocal recurrent selection in BSSS (BSSS(R)C17), denoted as C17 and the cross between BSSS(R)C0 and BSSS(R)C17 denoted as C0/C17. With the aim to explore if we have potentially lost diversity from C0 to C17 derived DH lines and observe whether useful genetic variation in C0 was left behind during the selection process since C0 could be a reservoir of genetic diversity that could be untapped using DH technology. Additionally, we quantify the contribution of the BSSS progenitors in each set of DH lines. The molecular characterization analysis confirmed the apparent separation and the loss of genetic variability from C0 to C17 through the recurrent selection process. Which was observed by the degree of differentiation between the C0_DHL versus C17_DHL groups by Wright's F-statistics (FST). Similarly for the population structure based on principal component analysis (PCA) revealed a clear separation among groups of DH lines. Some of the progenitors had a higher genetic contribution in C0 compared with C0/C17 and C17 derived DH lines. Although genetic drift can explain most of the genetic structure genome-wide, phenotypic data provide evidence that selection has altered favorable allele frequencies in the BSSS maize population through the reciprocal recurrent selection program.
对一组特定的玉米种质进行分子特征分析，有助于理解在育种计划中如何利用这些组合的种质进行进一步改良，例如分析遗传多样性、选择亲本系、划分杂种优势群、构建核心种质库和/或对感兴趣的性状进行关联分析。在本研究中，我们使用单核苷酸多态性（SNP）标记来评估一组双单倍体（DH）系的遗传变异性，这些DH系源自未经选择的爱荷华坚秆综合种（BSSS）玉米群体，记为C0（BSSS(R)C0），BSSS中轮回选择的第17代（BSSS(R)C17），记为C17，以及BSSS(R)C0和BSSS(R)C17之间的杂交种，记为C0/C17。目的是探究从C0到C17衍生的DH系是否可能丢失了多样性，并观察在选择过程中C0中是否留下了有用的遗传变异，因为C0可能是一个遗传多样性库，可以通过DH技术加以利用。此外，我们量化了每组DH系中BSSS亲本的贡献。分子特征分析证实，通过轮回选择过程，从C0到C17明显出现了分离和遗传变异性的丧失。这通过Wright的F统计量（FST）观察C0_DHL与C17_DHL组之间的分化程度得以体现。同样，基于主成分分析（PCA）得出的群体结构也显示DH系组之间有明显的分离。与C0/C17和C17衍生的DH系相比，一些亲本在C0中的遗传贡献更高。虽然遗传漂变可以解释全基因组的大部分遗传结构，但表型数据提供了证据，表明选择通过轮回选择计划改变了BSSS玉米群体中有利等位基因的频率。
