Ornamental crops play an indispensable role in enriching our daily lives, offering not just visual delight but also therapeutic benefits. Moreover, the floriculture industry stands as a pivotal pillar within the nation’s agriculture sector, experiencing a substantial 16% increase in sales from 2019-2022, marking it as one of the fastest-growing industries. Safeguarding ornamental plant diversity has become more crucial than ever to sustain this industry and ensure its continued growth and resilience in the face of climate changes and evolving consumer preferences. Located in Columbus, OH, the Ornamental Plant Germplasm Center (OPGC) is one of 20 gene banks in the U.S. National Plant Germplasm System. Established through a cooperative effort between the USDA-ARS and The Ohio State University, it began operations in 2001. The center’s main goals are to acquire, document, maintain, characterize, and distribute herbaceous ornamental genetic resources and associated information for conservation, and to enhance scientific research as well as the floriculture and nursery industry. Current priority genera include Begonia, Coreopsis, Lilium, Phlox, Rudbeckia, and Viola. Since the OPGC began operation, 7350 accessions have been acquired, representing significant diversity within the 432 genera and over 2000 species of herbaceous ornamentals conserved. More than 13,000 germplasm items have been delivered free of charge to researchers, breeders and educators around the world. This presentation will outline the core functions of OPGC, including its germplasm collection, conservation techniques, and collaborative research initiatives.
Studies on genetic diversity and population structure provide important insights for determining ancestry and target trait enhancement in breeding programs. Gladiolus(-i), Gladiolus ×hybridus (Iridaceae), is a tetraploid, asexually-propagated, herbaceous perennial floricultural crop. Gladioli have tall flower stalks which make them ideally suited for cut flowers (floral design) and annual garden plants. Gladiolus is an important cut flower crop (in the top 5) for floral design. The purpose of this study was to analyze the genetic diversity of cultivated gladiolus germplasm to determine ancestry and relatedness. In this study we examine 549 unique gladiolus cultivars using DNA marker-based analysis. Samples were collected from the public (University of Minnesota) and private (Meyer, Otto) sector breeding programs in Minnesota and Europe. Population genetic diversity was analyzed using 17,556 single nucleotide polymorphism (SNP) markers developed by low-density DArTseq technology. Despite phenotypic differences, primarily in flower color or type (ruffled, etc.), the genetic diversity of gladiolus cultivars is low. The heterozygosity value was Ho=0.09 and the Fischers (FHOM) inbreeding coefficient was FHOM=0.40. SplitsTrees showed no differentiation, the average minor allele frequency (MAF) and polymorphism information content (PIC) was MAF=0.12 and PIC=0.15. The lack of significant genetic diversity among cultivars as well as breeding programs demonstrates a narrow germplasm base for this important cut flower crop. We discuss our findings and recommend ways to use these conclusions to improve future genome-wide association studies (GWAS) as well as increase efficiency and diversity in breeding goals.
Marie Abbey is a researcher at the University of Minnesota Horticultural Science department. She has studied perceptions of biotechnology, invasive plant species, and aquaponics. Her current research is in flower breeding and molecular genetics.
Azaleas (Rhododendron spp.) are economically important ornamental flowering shrubs in landscapes around the world with thousands of cultivars representing many species of Rhododendron. Because azalea is an asexually propagated crop, potential discrepancies in plant identity may occur throughout the propagation pipeline, which can lead to mislabeling during propagation and commercialization processes. For example, the University of Minnesota (UMN) cultivar ‘Electric Lights Double Red’ is currently being propagated but flower morphology of the propagules differed from the original plant leading to uncertainty of propagule identity. Previous studies have identified DNA markers, specifically simple sequence repeats (SSRs), capable of differentiating azalea hybrid offspring from different species of the section Pentanthera. This study aims to leverage these previously developed SSR markers to authenticate the identity of breeding germplasm at the UMN and uniquely fingerprint other cultivars on the market. The evaluated azaleas pedigrees include up to 15 different species of deciduous azalea. Therefore, a total of 15 SSR markers that amplified fragments from several species of section Pentanthera were selected for this study. DNA was extracted from lyophilized leaf samples of 139 azalea cultivars using a Qiagen DNeasy Plant Pro Kit. Preliminary analysis of the azalea DNA using the selected SSR markers has identified the presence of 16 expected unique cultivars and 3 pairs of previously known duplicates. The outcome of this research will demonstrate the feasibility of providing azalea breeders, growers, and producers a marker-based system for assuring cultivar trueness-to-type and protection of intellectual property.
This comprehensive study unveils the first annotated, haplotype-resolved, chromosome-scale reference genome of Lantana camara, alongside insights into candidate genes for unreduced female gamete production through ovary transcriptome sequencing. L. camara, a native of the Caribbean, plays a dual role as a valued ornamental plant and a challenging invasive species. The absence of a high-quality genomic resource has previously limited the exploration of its ornamental and invasive characteristics. This work closes this gap by delivering a critical genomic resource for L. camara, essential for ornamental breeding programs and invasive species management. The genome of a diploid L. camara breeding line UF-T48 was assembled de novo, utilizing HiFi and Hi-C reads, achieving phased genome assemblies with a BUSCO score of 97.7% and LAI score of 19.37, indicating high quality. This assembly resolved all 22 chromosomes into pseudochromosomes, with an average length of 117 Mb, and annotated 83,775 protein-coding genes, laying a foundational step for Verbenaceae family genomic research. Simultaneously, this research delves into the plant’s reproductive biology, specifically targeting the mechanism of unreduced female gamete production, a trait that has played an important role in the evolution and spread of lantana, contributed to the plant’s invasiveness, and and complicated the development of sterile triploids. By aligning RNA-seq data to the reference genome, we identified differentially expressed genes associated with cell division and meiosis, crucial for understanding the genetic underpinnings of unreduced gamete production. These findings not only enhance the genetic comprehension of L. camara but also provide invaluable genomic resources for future genetic studies, conservation efforts, and breeding strategies aimed at producing non-invasive sterile cultivars. This pioneering genomic and transcriptomic analysis marks a significant leap forward in researchers’ ability to manipulate L. camara for both horticultural innovation and environmental management.
Flowering dogwoods (Cornus florida L.), known for their showy spring display and year-round appeal, are extensively planted as ornamental trees. In 2019, dogwoods ranked third in value for deciduous flowering trees in the U.S., generating more than $31 million in wholesale and retail sales. Tennessee is vital to this industry. The state leads the country in the number of dogwood plants sold, with almost double the number of trees sold as the next top producing state in the country. The showy bracts of dogwoods are modified leaves with a spectrum of color ranging from white to red, with many intermediate colors and patterns. Cornus florida ‘Cherokee Brave’ with deep pink bracts and ‘Appalachian Spring’ with creamy white bracts are two popular cultivars. Partially phased reference genomes have recently been assembled and annotated for these cultivars, ranging from 1,253 to 1,266 Mbp in length with 28,558 to 28,768 annotated protein coding genes. With these newly annotated genomes providing greater context, a QTL analysis was conducted using a pseudo-F2 population of ‘Cherokee Brave’ × ‘Appalachian Spring’ which segregates for bract color. Genotyping was completed using double-digest restriction-site associated DNA sequencing (ddRADseq) with PstI and MspI. With increasing demand for high-throughput phenotyping, six different phenotypic methods were utilized to determine which method was optimal for QTL detection. The phenotyping methods included: 1) manual characterization into binary classes (white or pink); 2) manual characterization into five classes (white, light blush, medium blush, pink, red); 3) colorimeter readings; 4) image analysis using full inflorescence; 5) image analysis using bracts detached from inflorescence; and 6) one bract per inflorescence. QTLs were identified using all phenotyping methods. The QTLs identified here will be used as the foundation for developing a marker assisted selection system for bract color in flowering dogwoods.
Hibiscus cannabinus, commonly referred to as Kenaf, is an annual warm-season plant that can thrive in the Southeastern United States. It serves as a vital source of natural fiber with diverse applications, such as biocomposites, paper pulp, textiles, industrial absorbents, animal bedding, and potting medium. A set of 86 accessions of Hibiscus cannabinus, acquired from USDA-GRIN, underwent evaluation in Central Florida for various parameters, including plant height, basal width, stem width 50 cm above the plant base, stalk fresh weight, stem fresh weight, stalk dry weight, leaf dry weight, bast weight, and core weight. Significant variations were observed among accessions for all the measured variables. Notably, stalk dry weight emerged as the key trait of interest, representing the plant portion with desirable fibers for various applications. The top Duncan grouping for stalk dry weight comprised eight accessions: PI 329191 (18-85), PI 639889 (18-157) known as "Whitten," PI 270111 (18-55) known as "G-32," PI 603071 (18-152) known as "Dowling," PI 638930 (18-154) known as "74200 I4," PI 638932 (18-156) known as "Yue 74-3," PI 270106 (18-50) known as "G-14," and PI 468077 (18-137). Out of the 86 USDA-GRIN accessions examined, these eight have been identified as the top-performing choices for field production in Central Florida. Furthermore, these selected accessions are deemed desirable parents for future cultivar improvement endeavors, aiming to develop enhanced cultivars of Hibiscus cannabinus specifically tailored for production in Central Florida.
