Quantitative descriptions of rice plant architecture and their application

Plant architecture is an important agronomic trait, and improving plant architecture has attracted the attention of scientists for decades, particularly studies to create desirable plant architecture for high grain yields through breeding and culture practices. However, many important structural phenotypic traits still lack quantitative description and modeling on structural-functional relativity. This study defined new architecture indices (AIs) derived from the digitalized plant architecture using the virtual blade method. The influences of varieties and crop management on these indices and the influences of these indices on biomass accumulation were analyzed using field experiment data at two crop growth stages: early and late panicle initiation. The results indicated that the vertical architecture indices (LAI, PH, 90%-DRI, MDI, 90%-LI) were significantly influenced by variety, water, nitrogen management and the interaction of water and nitrogen, and compact architecture indices (H-CI, Q-CI, 90%-LI, 50%-LI) were significantly influenced by nitrogen management and the interaction of variety and water. Furthermore, there were certain trends in the influence of variety, water, and nitrogen management on AIs. Biomass accumulation has a positive linear correlation with vertical architecture indices and has a quadratic correlation with compact architecture indices, respectively. Furthermore, the combination of vertical and compact architecture indices is the indicator for evaluating the effects of plant architecture on biomass accumulation.

株型是一类重要的农艺性状，数十年来，株型改良一直是植物科学领域的研究热点，其中通过育种与栽培手段培育高产优良株型的相关研究备受关注。然而，诸多关键的结构型表型性状仍缺乏针对结构-功能相关性的定量描述与建模方法。本研究采用虚拟叶片法对株型进行数字化表征，据此定义了一系列全新的株型指数（Architecture Indices, AIs）。本研究基于作物穗分化始期两个关键生育阶段——早期与晚期的田间试验数据，分别分析了品种与栽培管理措施对上述株型指数的调控效应，以及各株型指数对生物量积累的影响。结果表明，垂直株型指数包括叶面积指数（Leaf Area Index, LAI）、株高（Plant Height, PH）、90%-DRI、MDI、90%-LI，其显著受品种、水分管理、氮肥管理及其交互作用的影响；而紧凑株型指数包括H-CI、Q-CI、90%-LI、50%-LI，则显著受氮肥管理以及品种与水分的交互作用调控。此外，品种、水分与氮肥管理对株型指数的调控效应存在一定的规律性趋势。生物量积累与垂直株型指数呈显著正线性相关，而与紧凑株型指数则呈二次相关关系。进一步研究发现，垂直株型指数与紧凑株型指数的组合可作为评价株型对生物量积累调控效应的有效指标。