The goal of transgenesis in plant breeding is to make step-change improvements in traits of interest. However, improving quantitative traits, such as yield in maize (Zea mays L.), with transgenes has been difficult. Traditionally, transgene testing is done on a few isogenic lines, and results are extrapolated to entire breeding populations. Testing on limited germplasm does not provide a robust estimate of a transgene's value. Incorporating transgenes directly into breeding populations could increase genetic variance and the rate of genetic gain. Here, we used a transgene that reduces ethylene as a case study and investigated event, transgene, family, and environment effects and their interactions. We also determined whether introduction of the transgene into a breeding population would result in transgenic lines being preferentially selected over nontransgenic lines for yield. We found significant variation in transgene effects across clustered environments and families for multiple traits including yield. In environmental Cluster 2, the transgenic lines yielded 0.4 Mg ha⁻¹ more than nontransgenic lines in family KC22; yet, in family QY43, transgenic lines yielded 0.3 Mg ha⁻¹ less. Similarly, within Cluster 4, the QY43 family had preferential selection of transgenic over nontransgenic lines, whereas in families YE41 and AY91, nontransgenic lines were selected more frequently. These results show the critical importance of evaluating transgenes across broad germplasm diversity to assess their general value to a program. Integrating transgenes, or using gene editing, directly in a breeding program can expand genetic variation for quantitative traits and potentially accelerate genetic gain.

中文翻译：

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转基因效应因玉米种群而异，对改善数量性状有影响


植物育种中转基因的目标是对感兴趣的性状进行阶跃式改进。然而，用转基因改善数量性状，例如玉米 （Zea mays L.） 的产量一直很困难。传统上，转基因检测是在几个同基因系上进行的，结果被外推到整个育种种群。对有限的种质进行检测并不能对转基因的价值进行可靠的估计。将转基因直接纳入育种种群可以增加遗传变异和遗传增益率。在这里，我们使用一种减少乙烯的转基因作为案例研究，并研究了事件、转基因、家庭和环境影响及其相互作用。我们还确定了将转基因引入育种种群是否会导致转基因品系的产量优先于非转基因品系。我们发现包括产量在内的多个性状在聚类环境和家系中的转基因效应存在显著差异。在环境聚类 2 中，转基因品系比 KC22 家族中的非转基因品系多产 0.4 Mg ^ha-1;然而，在 QY43 家族中，转基因品系的产量减少了 0.3 Mg ^ha-1。同样，在聚类 4 中，QY43 家族优先选择转基因品系而不是非转基因品系，而在 YE41 和 AY91 品系中，非转基因品系的选择更频繁。这些结果表明，在广泛的种质多样性中评估转基因对于评估它们对项目的一般价值至关重要。将转基因或使用基因编辑直接整合到育种计划中可以扩大数量性状的遗传变异，并可能加速遗传增益。