Tolley Seth A, Singh Amritpal, Tuinstra Mitchell R
Department of Agronomy, Purdue University, West Lafayette, IN, United States.
Advanta Seeds, College Station, TX, United States.
Front Plant Sci. 2021 Jun 14;12:616975. doi: 10.3389/fpls.2021.616975. eCollection 2021.
As the plant variety protection (PVP) of commercial inbred lines expire, public breeding programs gain a wealth of genetic materials that have undergone many years of intense selection; however, the value of these inbred lines is only fully realized when they have been well characterized and are used in hybrid combinations. Additionally, while yield is the primary trait by which hybrids are evaluated, new phenotyping technologies, such as ear photometry (EP), may provide an assessment of yield components that can be scaled to breeding programs. The objective of this experiment was to use EP to describe the testcross performance of inbred lines from temperate and tropical origins. We evaluated the performance of 298 public and ex-PVP inbred lines and 274 Drought Tolerant Maize for Africa (DTMA) inbred lines when crossed to Iodent (PHP02) and/or Stiff Stalk (2FACC) testers for 25 yield-related traits. Kernel weight, kernels per ear, and grain yield predicted by EP were correlated with their reference traits with = 0.49, = 0.88, and = 0.75, respectively. The testcross performance of each maize inbred line was tester dependent. When lines were crossed to a tester within the heterotic group, many yield components related to ear size and kernels per ear were significantly reduced, but kernel size was rarely impacted. Thus, the effect of heterosis was more noticeable on traits that increased kernels per ear rather than kernel size. Hybrids of DTMA inbred lines crossed to PHP02 exhibited phenotypes similar to testcrosses of Stiff Stalk and Non-Stiff Stalk heterotic groups for yield due to significant increases in kernel size to compensate for a reduction in kernels per ear. Kernels per ear and ear length were correlated ( = 0.89 and = 0.84, respectively) with and more heritable than yield, suggesting these traits could be useful for inbred selection.
随着商业自交系的植物品种保护（PVP）到期，公共育种项目获得了大量经过多年高强度选择的遗传材料；然而，只有当这些自交系得到充分表征并用于杂交组合时，它们的价值才能得到充分体现。此外，虽然产量是评估杂交种的主要性状，但新的表型分析技术，如穗部光度测量（EP），可以提供对产量构成因素的评估，这些评估可以应用于育种项目。本实验的目的是利用EP来描述温带和热带来源的自交系的测交表现。我们评估了298个公共和过期PVP自交系以及274个非洲耐旱玉米（DTMA）自交系与Iodent（PHP02）和/或坚秆（2FACC）测验种杂交时25个与产量相关性状的表现。EP预测的粒重、每穗粒数和籽粒产量与其参考性状的相关性分别为r = 0.49、r = 0.88和r = 0.75。每个玉米自交系的测交表现取决于测验种。当自交系与杂种优势群内的测验种杂交时，许多与穗大小和每穗粒数相关的产量构成因素显著降低，但粒大小很少受到影响。因此，杂种优势对增加每穗粒数的性状的影响比对粒大小的影响更明显。DTMA自交系与PHP02杂交的杂交种在产量方面表现出与坚秆和非坚秆杂种优势群测交相似的表型，这是因为粒大小显著增加，以补偿每穗粒数的减少。每穗粒数和穗长与产量的相关性分别为r = 0.89和r = 0.84，且比产量更具遗传性，表明这些性状可用于自交系选择。
