Diversity

Intraspecific phenotypic diversity in clonally propagated crops is frequently constrained by narrow domestication histories and the widespread use of a limited number of elite cultivars. In Stevia rebaudiana, commercial production has largely centred on cv. ‘Morita II’, raising concerns about reduced diversity and adaptive potential. This study characterised and structured phenotypic diversity within a segregating population derived from ‘Morita II’ under tropical field conditions. Eighty-six progeny-derived genotypes (clonally propagated) plus the commercial control (87 genotypes total) were evaluated using 25 agromorphological descriptors (qualitative and quantitative). Quantitative traits showed broad variation, including plant height (28.26–119.50 cm) and dry yield rate (0.94–28.55 g plant⁻¹). Multivariate analyses of mixed descriptors (PCA and hierarchical clustering based on Gower distance) identified plant architecture, vegetative growth, and phenology as the main sources of differentiation. The first two principal components explained 19.65% and 12.58% of total phenotypic variance, respectively (32.23% cumulative). Hierarchical clustering (UPGMA; dissimilarity cut-off = 0.25) resolved four phenotypic groups (GI–GIV) with sizes n = 3, 1, 66, and 17, respectively, enabling the definition of contrasting ideotype candidates based on recurrent trait combinations. These results provide a quantitative baseline for phenotypic structuring, prioritization of materials for further evaluation, and management of clonal stevia collections in tropical production systems. These ideotype candidates should be considered preliminary until validated across environments and linked to chemical quality traits.

Juncus (Juncaceae) comprises over 300 species with high morphological plasticity, and its systematics remain incompletely resolved due to limited genomic resources. Here, we generated complete plastid genomes for two Korean Juncus species (J. decipiens and J. gracillimus) and incorporated plastid coding genes from an additional species to reconstruct phylogenetic relationships and examine plastome evolution within Juncaceae. Comparative analyses revealed substantial plastome size variation across Juncus and Luzula, largely driven by changes in inverted repeat (IR) length, with Luzula plastomes showing pronounced IR expansion. Within Juncus, extensive structural rearrangements were detected, including multiple inversion events, and closely related taxa shared conserved inversion patterns. Phylogenomic analyses recovered well-supported clades that were associated with structural traits such as extreme small single-copy (SSC) contraction and consistent loss of the plastid ndh, some rps and rpl gene families, indicating clade-specific plastome evolution in Juncaceae. To support applied molecular identification, we identified J. decipiens-specific plastid diagnostic SNPs (matK, rpl2) and validated allele-specific PCR markers using individuals from different species within the Juncus genus. In parallel, transcriptome sequencing of J. decipiens generated 133,559 transcripts and 66,324 unigenes, enabling discovery of high-confidence nuclear exonic SNP loci by mapping reads to a J. effusus nuclear genome. Collectively, our results provide new insights into plastome structural evolution and gene loss in Juncus and deliver validated plastid and nuclear markers for authentication and future conservation or utilisation studies on J. decipiens.

Afrotropical inland waters remain poorly studied for rotifer diversity. Here, we provide new distribution data from Botswana and connect these local patterns to continental-scale biogeography using an Africa–Europe occurrence dataset. In Botswana, we analyzed rotifer species richness, functional traits, and environmental drivers using 37 samples from 15 water bodies spanning natural and anthropogenic habitats. We recorded 107 rotifer taxa: 92 identified to species or subspecies level and 14 to genus. Seventy taxa (~65%) are new records for Botswana, and one species, Donneria sudzukii, is reported for the first time in Africa. Physicochemical gradients explained community structure, with the first two constrained RDA axes accounting for 40.7% and 23.7% of variation. Axis 1 captured a mineralization gradient linked to total dissolved solids and temperature, whereas Axis 2 reflected oxygen concentration and pH. Traits tracked these gradients: warmer, more mineralized waters were associated with specific trophi types, compact body shapes, and intermediate body sizes, whereas less mineralized, better oxygenated sites were related to smaller taxa and alternative feeding morphologies. To place these trait–environment relationships in a broader geographic context, we then analyzed an Africa–Europe dataset (67,170 records) to quantify latitudinal patterns in thermal classes and morphological traits (geometric body shape and trophi type). Diversity showed clear latitudinal structuring: warm-water genera clustered at low latitudes, only Kellicottia and Didymodactylos had mean distributions above 50° N, and bdelloid families were associated with higher latitudes. Morphological traits also varied with latitude, with trilateral truncated pyramid body shapes and malleoramate trophi occurring closest to the equator. Overall, by combining new species-level data from Botswana with continent-scale occurrence patterns, we link local community assembly to macroecological structure in rotifer functional and biogeographical organization.