Intra-leaf modeling ofCannabisleaflet shape produces synthetic leaves that predict genetic and developmental identities

Abstract

SummaryThe iconic, palmately compound leaves ofCannabishave attracted significant attention in the past. However, investigations into the genetic basis of leaf shape or its connections to phytochemical composition have yielded inconclusive results. This is partly due to prominent changes in leaflet number between leaves of a single plant during development, which has until this point prevented the proper use of common morphometric techniques.Here we present a new method that overcomes the challenge of nonhomologous landmarks inCannabis. By modeling leaflet shape as a function of angle within a leaf, we create synthetic leaves with comparable numbers of leaflets to which morphometric analysis is applied.We analyze 339 leaves from 24 individuals from nineCannabisaccessions, including both wild/feral accessions and cultivated varieties. Using 1,995 pseudo-landmarks in synthetic leaves, we visualize a morphospace and accurately predict accession identity, leaflet number, and relative node number.Intra-leaf modeling offers a rapid, cost-effective means of identifyingCannabisaccessions, making it a valuable tool for future taxonomic studies, cultivar recognition, and possibly chemical content analysis and sex identification, in addition to permitting the morphometric analysis of leaves in any species with variable numbers of leaflets or lobes.