Pioneer Hi-Bred, A DuPont Business, 7250 NW 62nd Avenue, Johnston, IA 50131, USA.
J Exp Bot. 2011 Jan;62(3):855-68. doi: 10.1093/jxb/erq329. Epub 2010 Nov 1.
The effectiveness of breeding strategies to increase drought resistance in crops could be increased further if some of the complexities in gene-to-phenotype (G → P) relations associated with epistasis, pleiotropy, and genotype-by-environment interactions could be captured in realistic G → P models, and represented in a quantitative manner useful for selection. This paper outlines a promising methodology. First, the concept of landscapes was extended from the study of fitness landscapes used in evolutionary genetics to the characterization of yield-trait-performance landscapes for agricultural environments and applications in plant breeding. Second, the E(NK) model of trait genetic architecture was extended to incorporate biophysical, physiological, and statistical components. Third, a graphical representation is proposed to visualize the yield-trait performance landscape concept for use in selection decisions. The methodology was demonstrated at a particular stage of a maize breeding programme with the objective of improving the drought tolerance of maize hybrids for the US Western Corn-Belt. The application of the framework to the genetic improvement of drought tolerance in maize supported selection of Doubled Haploid (DH) lines with improved levels of drought tolerance based on physiological genetic knowledge, prediction of test-cross yield within the target population of environments, and their predicted potential to sustain further genetic progress with additional cycles of selection. The existence of rugged yield-performance landscapes with multiple peaks and intervening valleys of lower performance, as shown in this study, supports the proposition that phenotyping strategies, and the directions emphasized in genomic selection can be improved by creating knowledge of the topology of yield-trait performance landscapes.
如果能够在现实的 G→P 模型中捕捉到与上位性、多效性和基因型-环境互作相关的基因-表型（G→P）关系的某些复杂性，并以对选择有用的定量方式表示，那么增加作物抗旱性的繁殖策略的有效性可以进一步提高。本文概述了一种很有前途的方法。首先，从进化遗传学中用于研究适合度景观的概念扩展到了农业环境中产量性状表现景观的特征化及其在植物育种中的应用。其次，将性状遗传结构的 E（NK）模型扩展为包含生物物理、生理和统计成分。第三，提出了一种图形表示方法来可视化产量性状表现景观的概念，以便用于选择决策。该方法在一个特定的玉米育种计划阶段进行了演示，目的是提高美国西部玉米带玉米杂交种的抗旱性。该框架在玉米抗旱性遗传改良中的应用支持了基于生理遗传知识选择抗旱性提高的加倍单倍体（DH）系，预测了目标环境群体中的测验交产量，并预测了它们在进一步选择循环中具有持续遗传进展的潜力。如本研究所示，具有多个峰值和中间较低性能山谷的崎岖产量表现景观的存在，支持了这样一种观点，即表型策略以及基因组选择中强调的方向可以通过创建产量性状表现景观的拓扑知识来改进。
