Department of Trait and Technology Development, Pioneer Hi-Bred International, Inc., P.O. Box 1004, 50131, Johnston, IA, USA.
Theor Appl Genet. 1995 Sep;91(4):574-81. doi: 10.1007/BF00223282.
Resistance to the soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) is difficult to evaluate in soybean [Glycine max (L.) Merr.] breeding. PI 437.654 has resistance to more SCN race isolates than any other known soybean. We screened 298 F6∶7 recombinant-inbred lines from a cross between PI 437.654 and 'BSR101' for SCN race-3 resistance, genetically mapped 355 RFLP markers and the I locus, and tested these markers for association with resistance loci. The Rhg 4 resistance locus was within 1 cM of the I locus on linkage group A. Two additional QTLs associated with SCN resistance were located within 3cM of markers on groups G and M. These two loci were not independent because 91 of 96 lines that had a resistant-parent marker type on group G also had a resistant-parent marker type on group M. Rhg 4 and the QTL on G showed a significant interaction by together providing complete resistance to SCN race-3. Individually, the QTL on G had greater effect on resistance than did Rhg 4, but neither locus alone provided a degree of resistance much different from the susceptible parent. The nearest markers to the mapped QTLs on groups A and G had allele frequencies from the resistant parent indicating 52 resistant lines in this population, a number not significantly different from the 55 resistant lines found. Therefore, no QTLs from PI 437.654 other than those mapped here are expected to be required for resistance to SCN race-3. All 50 lines that had the PI 437.654 marker type at the nearest marker to each of the QTLs on groups A and G were resistant to SCN race-3. We believe markers near to these QTLs can be used effectively to select for SCN race-3 resistance, thereby improving the ability to breed SCN-resistant soybean varieties.
大豆孢囊线虫（SCN）（Heterodera glycines Ichinohe）抗性在大豆[Glycine max（L.）Merr.]育种中难以评估。PI 437.654 对比任何已知的大豆具有更多的 SCN 分离株抗性。我们从 PI 437.654 和 'BSR101' 的杂交后代中筛选了 298 个 F6∶7 重组自交系，用于 SCN 分离株 3 抗性，遗传图谱 355 个 RFLP 标记和 I 位点，并测试这些标记与抗性基因座的相关性。Rhg 4 抗性基因座位于连锁群 A 上 I 基因座的 1cM 内。与 SCN 抗性相关的另外两个 QTL 位于标记在 G 和 M 组的 3cM 内。这两个位点不是独立的，因为在 G 组具有抗性亲本标记类型的 96 个系中有 91 个也具有 M 组的抗性亲本标记类型。Rhg 4 和 G 上的 QTL 表现出显著的相互作用，因为它们共同提供了对 SCN 分离株 3 的完全抗性。单独地，G 上的 QTL 对抗性的影响大于 Rhg 4，但它们单独都不能提供与感病亲本有很大不同的抗性程度。映射到 A 和 G 组的 QTL 附近的最近标记具有来自抗性亲本的等位基因频率，表明在该群体中有 52 个抗性系，数量与发现的 55 个抗性系没有显著差异。因此，除了这里映射的那些，PI 437.654 上的其他 QTL 预计不需要对 SCN 分离株 3 具有抗性。在 A 和 G 组的最近标记附近具有 PI 437.654 标记类型的所有 50 个系都对 SCN 分离株 3 具有抗性。我们相信这些 QTL 附近的标记可以有效地用于选择 SCN 分离株 3 抗性，从而提高培育 SCN 抗性大豆品种的能力。
