Morphological diversity among Andrographis paniculata genotypes based on traits determined mainly by high-throughput phenotyping platform

Andrographis paniculata is widely cultivated across China and Southeast Asia due to its therapeutic benefits in traditional medicine for various ailments. The species is rich in bioactive metabolites, particularly andrographolide, with significant anti-inflammatory and antimicrobial properties. Efficient large-scale production of andrographolide requires a comprehensive understanding of the genetic and phenotypic diversity of A. paniculata. This study characterized 38 accessions of Thai A. paniculata for 15 traits, including days-to-flowering, biomass, andrographolide content, and 10 morphometric traits measured by high-throughput phenotyping platforms (HTPPs). Utilizing both manual measurements and HTPPs, this research reveals significant phenotypic variability among these accessions, particularly in days-to-flowering, plant height, and plant canopy shape. Andrographolide content ranged from 37.4 to 51.0 mg g⁻¹ dry weight, indicating significant bioactive compound diversity. Clustering analysis based on phenotypic data classified the accessions into two to three groups. Andrographolide yield per plant was associated with morphological traits such as plant weight and dimensions. HTPPs were able to capture complex plant architecture traits such as compactness and roundness, which showed correlations with andrographolide yield. Several accessions having interesting traits such as high andrographolide content, high biomass, high andrographolide yield per plant, a small symmetrical rapid-cycling type, and high andrographolide content and andrographolide yield per plant were identified. This pioneering application of HTPP in A. paniculata research offers new insights into its phenotypic diversity, thus contributing to the sustainable utilization and conservation of the species.