Location: Subtropical Horticulture Research
2020 Annual Report
Objectives
Objective 1: Efficiently and effectively maintain the safety, genetic integrity, health, and viability of subtropical and tropical ornamental genetic resources, and distribute them and associated information worldwide.
Subobjective 1A: Strategically expand and improve collections of priority tropical and subtropical ornamental taxa and associated information.
Subobjective 1B: Conserve, regenerate, and distribute as needed subtropical and tropical ornamental genetic resources and information efficiently and effectively, emphasizing priority genera identified by Crop Germplasm Committees (CGCs).
Objective 2: Develop more effective genetic resource characterization, phylogenetic analyses, and evaluation methods, and apply them to priority subtropical and tropical ornamental genetic resources. Record and disseminate evaluation and characterization data via GRIN-Global and other data sources.
Subobjective 2A: Develop nearly complete whole plastome and low copy nuclear gene sequences to generate well-resolved phylogenies of various clades of Amaryllidaceae.
Subobjective 2B: Elucidate the genetic control of anthocyanin pigmentation in the genera Hippeastrum (amaryllis), Worsleya, and Griffinia, and fragrance production in Hippeastrum.
Objective 3: Guided by new knowledge of the genetic relationships and valuable ornamental traits of poorly-known plants, develop superior new cultivars and genetically-enhanced populations and/or selections of priority subtropical and tropical ornamental crops.
Subobjective 3a. Select, breed, and/or release new cultivars of the subtropical/ tropical shrub Portlandia, the flowering tree genus Tabebuia (inc. Handroanthus), and other tropical/subtropical taxa.
Subobjective 3b: Continue evaluation and selection of Hippeastrum hybrid progeny.
Approach
The long term objectives of this project are to ensure a secure and diverse stream of new genetic variation and enhanced germplasm for the subtropical/tropical ornamental horticulture industry as well as generate and consolidate detailed information about the intrinsic genetic variability, systematic relationships, and ornamental merit of genetic resources via genetic characterization, systematic studies, and field evaluation. These objectives are a combination of hypothesis-driven and non-hypothesis driven research. The objectives form an integrated program of subtropical/tropical ornamental germplasm characterization, enhancement and improved management practices. The program efficiently and effectively maintains the safety, genetic integrity, health, and viability of subtropical and tropical ornamental genetic resources. Collections of priority tropical and subtropical ornamental taxa and associated information will be strategically expanded and improved, distributing them worldwide to customers and stakeholders, emphasizing priority genera identified by appropriate Crop Germplasm Committees.
Nearly complete whole plastomes and many low copy nuclear gene sequences will be obtained to generate well-resolved phylogenies of various clades of Amaryllidaceae. The genetic control of anthocyanin pigmentation in the genera Hippeastrum (amaryllis), Worsleya, and Griffinia, and fragrance production in Hippeastrum will be elucidated.
Guided by new knowledge of the genetic relationships and valuable ornamental traits of poorly-known plants, superior new cultivars and genetically enhanced populations and/or selections of priority subtropical and tropical ornamental crops will be developed, with emphasis on the tropical shrub Portlandia, the flowering tree genus Tabebuia (inc. Handroanthus), and other tropical/subtropical taxa.
The evaluation and selection of Hippeastrum hybrid progeny will be continued. Hybrid progeny from the past few years, many of which are just reaching flowering size, will be evaluated for floral phenotype and flowering behavior, with selections made based on novel flower coloration, patterning, fragrance, and both bud and scape number.
Progress Report
ARS scientists in Miami, Florida, completed the analysis of molecular data for 100 species of Amaryllidaceae including the genus Hymenocallis and the tribe Clinantheae. Data included partial DNA sequences of 524 nuclear genes totaling 730,500 base pairs (bp) and partial plastome sequences of about 113,000 bp. ARS scientists, at Miami, Florida, isolated RNA from flower tepals of 2 species of Hippeastrum and have them sequenced by a service lab. These transcriptome data are being analyzed for genes involved in anthocyanin biosynthesis. Over 380 different accessions with 2,911 propagules (i.e., seeds, budwood, rhizomes, corms) were distributed to 15 states in the U.S and 3 international organizations. The ornamental germplasm collection is undergoing intensive management which has been absent for some years.
Accomplishments
1. New taxonomic classification of the Andean Amaryllidaceae. A new species of Paramongaia, P. multiflora, and of Rauhia, R. albescens, were described from Peru by ARS scientists in Miami, FLorida. An updated tree of life analysis of aligned DNA sequences across the Andean Amaryllidaceae that groups both Paramongaia species with three species of Clinanthus was presented. An expanded concept of the genus Paramongaia for all five species was proposed and the necessary taxonomic changes were made. Paramongaia was morphologically delimited from Clinanthus by the erect, uniformly waxy leaves, the fusion of the floral bracts on one side, and the insertion of the free filaments below the rim of the staminal cup. A key to the species of Paramongaia was provided. ARS scientists, at Miami, Florida, additionally presented some taxonomic notes on the genus Stenomesson. This research advances the taxonomic classification of the Amaryllidaceae.
2. Discovery of new Amaryllidaceae species. ARS scientists in Miami, Florida, described two new species from South America that belong to the amaryllis family (Amaryllidaceae), an important group of ornamental flower bulbs. Clinanthus inflatus and Ismene virescens) are both found in the Andes of Peru. ARS scientists, at Miami, Florida, also transferred a mis-diagnosed name, Stenomesson rubrum, into Clinanthus as C. ruber. This contribution clarifies the taxonomy of this highly diverse ornamental family and increases our understanding of its biodiversity in the Americas.
Review Publications
Meerow, A.W., Nakamura, K. 2019. Two new species of Peruvian Amaryllidaceae, an expanded concept of the genus Paramongaia, and taxonomic notes in Stenomesson. Phytotaxa. 416(2):184-196.
Meerow, A.W., Cano Echevarria, A.A. 2019. Taxonomic novelties in Amaryllidaceae from the Department of Ancash, Peru, and a new combination in Clinanthus. PHYTOKEYS. 131:115-126.
