Yang Qing, Yang Yongqing, Xu Ruineng, Lv Huiyong, Liao Hong
Root Biology Center, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China.
Front Plant Sci. 2019 Feb 1;10:75. doi: 10.3389/fpls.2019.00075. eCollection 2019.
Soybean is an important economic and green manure crop that is widely used in intercropping and rotation systems due to its high biological nitrogen fixation (BNF) capacity and the resulting reduction in N fertilization. However, the genetic mechanisms underlying soybean BNF are largely unknown. Here, two soybean parent genotypes contrasting in BNF traits and 168 F recombinant inbred lines (RILs) were evaluated under four conditions in the field. The parent FC1 always produced more big nodules, yet fewer nodules in total than the parent FC2 in the field. Furthermore, nodulation in FC1 was more responsive to environmental changes than that in FC2. Broad-sense heritability ( ) for all BNF traits varied from 0.48 to 0.87, which suggests that variation in the observed BNF traits was primarily determined by genotype. Moreover, two new QTLs for BNF traits, and , were identified in this study. The locus was detected under all of the four tested conditions, where it explained 15.9-59.0% of phenotypic variation with LOD values of 6.31-32.5. Meanwhile explained 12.6-18.6% of observed variation with LOD values of 4.93-7.51. Genotype group analysis indicated that the FC1 genotype of primarily affected nodule size (NS), while the FC2 genotype of promoted nodule number (NN). On the other hand, the FC1 genotype of influenced NN and the FC2 genotype of impacted NS. The results on the whole suggest that these two QTLs might be valuable markers for breeding elite soybean varieties with high BNF capacities.
大豆是一种重要的经济作物和绿肥作物，因其具有较高的生物固氮能力以及由此减少氮肥施用量，而被广泛应用于间作和轮作系统。然而，大豆生物固氮的遗传机制在很大程度上尚不清楚。在此，在田间的四种条件下对两个生物固氮性状具有差异的大豆亲本基因型和168个F重组自交系（RIL）进行了评估。在田间，亲本FC1总是产生更多的大根瘤，但根瘤总数比亲本FC2少。此外，FC1的根瘤形成比FC2对环境变化更敏感。所有生物固氮性状的广义遗传力（ ）在0.48至0.87之间，这表明观察到的生物固氮性状的变异主要由基因型决定。此外，在本研究中鉴定出了两个生物固氮性状的新QTL，即 和 。 位点在所有四种测试条件下均被检测到，在该位点它解释了15.9 - 59.0%的表型变异，LOD值为6.31 - 32.5。同时， 解释了12.6 - 18.6%的观察变异，LOD值为4.93 - 7.51。基因型组分析表明， 的FC1基因型主要影响根瘤大小（NS），而 的FC2基因型促进根瘤数量（NN）。另一方面， 的FC1基因型影响NN且 的FC2基因型影响NS。总体结果表明，这两个QTL可能是培育具有高生物固氮能力的优良大豆品种的有价值标记。
