Institute of Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, Stuttgart, Germany.
PLoS One. 2013;8(2):e57234. doi: 10.1371/journal.pone.0057234. Epub 2013 Feb 22.
Landraces are valuable genetic resources for broadening the genetic base of elite germplasm in maize. Extensive exploitation of landraces has been hampered by their genetic heterogeneity and heavy genetic load. These limitations may be overcome by the in-vivo doubled haploid (DH) technique. A set of 132 DH lines derived from three European landraces and 106 elite flint (EF) lines were genotyped for 56,110 single nucleotide polymorphism (SNP) markers and evaluated in field trials at five locations in Germany in 2010 for several agronomic traits. In addition, the landraces were compared with synthetic populations produced by intermating DH lines derived from the respective landrace. Our objectives were to (1) evaluate the phenotypic and molecular diversity captured within DH lines derived from European landraces, (2) assess the breeding potential (usefulness) of DH lines derived from landraces to broaden the genetic base of the EF germplasm, and (3) compare the performance of each landrace with the synthetic population produced from the respective DH lines. Large genotypic variances among DH lines derived from landraces allowed the identification of DH lines with grain yields comparable to those of EF lines. Selected DH lines may thus be introgressed into elite germplasm without impairing its yield level. Large genetic distances of the DH lines to the EF lines demonstrated the potential of DH lines derived from landraces to broaden the genetic base of the EF germplasm. The comparison of landraces with their respective synthetic population showed no yield improvement and no reduction of phenotypic diversity. Owing to the low population structure and rapid decrease of linkage disequilibrium within populations of DH lines derived from landraces, these would be an ideal tool for association mapping. Altogether, the DH technology opens new opportunities for characterizing and utilizing the genetic diversity present in gene bank accessions of maize.
地方品种是拓宽玉米优异种质遗传基础的宝贵遗传资源。由于其遗传异质性和遗传负荷过重，对地方品种的广泛开发受到了阻碍。这些限制可以通过体内加倍单倍体 (DH) 技术来克服。一组来自三个欧洲地方品种和 106 个优良硬质玉米 (EF) 品系的 132 个 DH 系被用于 56110 个单核苷酸多态性 (SNP) 标记的基因型分析，并于 2010 年在德国的五个地点进行了田间试验，评估了几个农艺性状。此外，还将地方品种与由各自地方品种的 DH 系互交产生的合成群体进行了比较。我们的目标是：(1) 评估源自欧洲地方品种的 DH 系中捕获的表型和分子多样性；(2) 评估源自地方品种的 DH 系拓宽 EF 种质遗传基础的育种潜力 (有用性)；(3) 将每个地方品种的表现与各自 DH 系产生的合成群体进行比较。源自地方品种的 DH 系之间存在较大的基因型方差，使得可以鉴定出与 EF 系相当的粒产量的 DH 系。因此，所选的 DH 系可以被导入优良的种质，而不会降低其产量水平。DH 系与 EF 系之间的遗传距离较大，表明源自地方品种的 DH 系具有拓宽 EF 种质遗传基础的潜力。地方品种与各自的合成群体的比较表明，没有产量提高，也没有表型多样性降低。由于源自地方品种的 DH 系群体的遗传结构低，群体内的连锁不平衡迅速下降，因此它们将成为关联作图的理想工具。总之，DH 技术为表征和利用玉米基因库材料中存在的遗传多样性提供了新的机会。
