Postdoctoral Associate Donald Danforth Plant Science Center
Disclosure: Disclosure information not submitted.
The morphological basis of plant architecture, such as of the inflorescence or the root, is difficult to convert into informative and measurable features. Therefore, most methods for capturing plant phenotype and analyzing the resulting data are limited to a few easily obtainable parameters that may miss the rich underlying diversity. Here, we combined X-ray computed tomography (XRT) with detailed morphometrics, developing new imaging and computational tools to analyze 3D organ architecture. To show the power of this approach, we first focused on the compound inflorescences of Sorghum bicolor. Sorghum inflorescences vary extensively in the numbers, lengths, and angles of primary branches, as well as the three-dimensional shape, size and distribution of the seed. Both qualitative and quantitative assessments of panicle diversity in sorghum have long been problematic, with most studies to date requiring significant simplification of the inflorescence components. By imaging and comprehensively evaluating inflorescence morphology from numerous accessions within the US sorghum association panel (SAP), we show that sorghum panicle architecture is highly continuous and does not follow overall genetic background, suggesting that localized genetic differences have been exploited to generate large distinctions between relatively closely-related cultivars. We similarly utilized XRT to quantify over 1000 root crowns from accessions within the SAP, using the high-resolution scans to estimate root system architecture features with greater accuracy due to the inherent advantage of 3D imaging, while accounting for above-ground tiller number variation when appropriate. Together, our approach demonstrates how 3D phenotyping can be leveraged to dissect complex traits into their fundamental biological components, enabling deeper analysis of plant architecture.