Morphometric approaches to promote the use of exotic germplasm for improved food security and resilience to climate change: a kura clover example

Adaptation of agriculture to climate change and its associated ecological pressures will require new crops, novel trait combinations, and previously unknown phenotypic attributes to deploy in climate resilient cropping systems. Genebanks, a primary source of exotic germplasm for novel crops and breeding materials, need comprehensive methods to detect novel and unknown phenotypes without a priori information about the species or trait under consideration. We demonstrate how persistent homology (PH) and elliptical Fourier descriptors (EFD), two morphometric techniques easily applied to image-based data, can serve this purpose by cataloging leaf morphology in the USDA NPGS kura clover collection and demarcating a leaf morphospace for the species. Additionally, we identify a set of representative accessions spanning the leaf morphospace and propose they serve as a kura clover core collection. The core collection will be a framework for monitoring the effects of climate change on kura clover in situ diversity and determining the role of ex situ accessions in modern agriculture.