Polyploidization is known to cause changes in the ploidy levels of plant somatic cells that affect the morphological, physiological and chemical composition. The aim of this research was to investigate the effects of tetraploidization in olive. To do this, several characteristics of 1-year-old shoots of two olive genotypes were compared: the diploid cultivar Leccino (L), and its tetraploid mutant Leccino Compact (LC), considered a slow-growing genotype. LC differed significantly from L in the morphological characteristics, with higher values of diameter, dry mass and volume of the stem (46%, 103%, 102%, respectively), and higher area, mass and volume of the individual leaf (43%, 66%, 73%, respectively). LC also had thicker, longer and wider leaves (30%, 10%, 34%, respectively) and significantly lower leaf density (7%) and lower specific leaf area, leaf mass ratio and leaf area ratio (17%, 4%, 18%, respectively). Internode length and stem density were not significantly different. The results allowed us to thoroughly characterize the effects of tetraploidy on 1-year-old shoots in olive, and also suggest that the slow growth of LC is due to its lower leaf area per unit of total biomass, which reduces leaf area production and, consequently, light interception, resource availability and tree growth. These results will be useful for genetic improvement programmes and for planning further exploitation of tetraploidy in horticulture.

Genetic diversity and phytochemical content are critical factors for enhancing the utility of wild plant species for breeding and conservation. In this study, we investigated wild ramie (Boehmeria nivea (L.) Gaudich. var. tenacissima (Roxb.) Miq.) populations from six coastal and island regions of South Korea. Genetic diversity was assessed in 150 samples using genotyping-by-sequencing, which revealed high genetic differentiation (Fst = 0.438) among the populations. Notably, the observed heterozygosity ranged from 0.297 to 0.422, whereas the allele richness ranged from 1.256 to 1.323. These findings suggest significant genetic variability within and among the populations. Phytochemical analyses were conducted to measure total phenolic and flavonoid contents (TPC and TFC, respectively) over 2 years. The TPC varied significantly across regions and years, with averages ranging from 2.2 to 30.3 mgGAE/g in 2021 and 3.2 to 19.6 mgGAE/g in 2022. Similarly, the TFC values exhibited regional and annual differences with significant environmental influences. Although TPC showed strong genotype-by-environment interactions, TFC was predominantly affected by environmental factors. This study highlights the potential of wild ramie as a reservoir of genetic and biochemical traits for the development of improved cultivars with high antioxidant properties. By linking genetic diversity to phytochemical variation, this study highlights the importance of conserving wild genetic resources and optimizing their use in breeding programmes. These findings provide a foundation for further exploration of the genetic and environmental factors that influence economically valuable traits in wild plants.

This work analyses the genetic potential of Stevia rebaudiana beyond its sweetening properties, aiming to reassess its conservation and utilization in breeding programmes. This focus is justified by the growing global demand for natural sweeteners and the challenges posed by extreme weather events and diseases affecting crop yield and quality. The relationship between the species’ genetic diversity and its response to biotic and abiotic stresses is explored, as well as the limitations of current conservation and breeding strategies. Findings reveal underutilized genetic resources, limited integration of genomic tools in breeding efforts and a lack of robust in situ conservation initiatives. Genotypic variability has been observed in response to diseases such as Septoria leaf spot, while abiotic factors, including salinity and drought, can significantly influence steviol glycoside content. It is concluded that an integrated approach, combining dynamic conservation, photoperiod‐informed breeding strategies, improvements in seed viability, omics‐based tools and coherent public policies, is essential to ensure crop resilience and genetic sovereignty, especially in regions of origin such as Paraguay. The sustainable use of Stevia’s genetic diversity could foster more sustainable, healthier and fairer production systems.

Yiyang Dahegu rice (YyDHG) is an important agricultural specialty of Yiyang County, Jiangxi Province, and it is also a significant component of the local cultural and economic development. In this experiment, 89 samples of Dahegu rice (DHG) were collected from Jiangxi Province, including 52 samples of YyDHG and 37 samples of DHG from other regions within Jiangxi Province (oDHG). Comprehensive analysis was conducted using polyacrylamide gel electrophoresis, field phenotypic observation, population structure analysis and quality analysis. The results of variety identification indicated that the 89 samples actually comprised 52 distinct varieties, including 19 varieties of YyDHG. Population analysis has revealed rich genetic diversity among DHG varieties within Jiangxi Province, yet no significant subpopulation differentiation was observed between YyDHG and oDHG. Quality experiments demonstrated that YyDHG exhibits significant differences in appearance quality from oDHG, but no notable differences in milling quality or cooked taste and flavour. This suggests that the competitiveness of YyDHG in the market may not entirely depend on its unique quality characteristics, but rather more on its cultural value and brand effect. This experiment conducted a comprehensive analysis of the variety characteristics, genetic diversity and quality traits of YyDHG. Not only does it provide a scientific basis for the breeding and germplasm resource conservation of YyDHG, but it also holds positive implications for promoting the development of its industry.

Dyckia ibiramensis is an endemic species from southern Brazil, known for its ability to adapt to extreme environmental variations. This study reports the development of species-specific microsatellite markers and the assembly and annotation of the plastid genome of D. ibiramensis, aiming to generate new genomic resources useful for studies on the conservation and evolution of this endangered species. A total of 33,112 microsatellite loci were identified, of which 10 were selected and validated for genotyping 30 individuals from natural populations, showing high genetic variability. These 10 microsatellite markers were very informative for the evaluation of genetic variability. These microsatellite markers evidenced moderate to high genetic diversity at the individual level, low population differentiation, and the capacity of the species to recover population size from ancient genetic bottlenecks. The assembled plastid genome revealed conserved structures and the occurrence of features at the gene level, likely related to stress response to environmental conditions. This study expands the understanding of the genetics of D. ibiramensis, highlighting the importance of genomic strategies for the conservation of endangered species. In situ and ex situ conservation strategies should be used to avoid the extinction of this endemic southern Brazilian genetic resource in nature.

Drought, salt and low-temperature stress significantly reduce the germination rate of cotton seeds. Additionally, the seed composition of seeds, including protein, oil and gossypol, are also closely linked to germination performance. This study assessed the seed composition of 120 cotton genotypes and their ability to germinate under drought, salt, and low-temperature stress, and compared with under standard conditions (control). Stress resistance during the germination stage was comprehensively evaluated using principal component analysis (PCA), which categorized the genotypes into three groups: 35 high-stress tolerance, 74 medium-stress tolerance and 11 medium sensitivity. Subordinate function analysis revealed that the comprehensive resistance D values of the 120 genotypes ranged from 0.20 to 1.12. Correlation analysis showed a significant negative correlation between seed oil content and germination under drought and salt stress (R = −0.27** and R = −0.24**). Additionally, germination under drought and salt stress were positively correlated (R = 0.58***). SNP_A07_90682411-based Kompetitive Allele-Specific PCR (KASP) markers identified that AA-type genotypes had significantly higher D values for comprehensive stress tolerance, drought resistance and salt resistance at the germination stage compared to GG-type genotypes (P = 0.0003, P = 0.010, and P = 0.0004, respectively). This study identified highly resistant and sensitive genotypes to various abiotic stresses, during germination and demonstrated that the ability of the newly developed KASP molecular markers effectively differentiate comprehensive germination performance under stress. These findings provide valuable references for understanding stress tolerance mechanisms during germination and breeding stress-tolerant cotton varieties.