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Propagation Methods for the Conservation and Preservation of the Endangered Whorled Sunflower (Helianthus verticillatus)

Helianthus verticillatus Small, the whorled sunflower, is a perennial species only found at a few sites in the southeastern United States and was declared federally (USA) endangered in 2014. The species spreads locally via rhizomes and can produce copious seeds when sexually compatible genotypes are...

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Autores principales: Trigiano, Robert N., Boggess, Sarah L., Wyman, Christopher R, Hadziabdic, Denita, Wilson, Sandra
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8399636/
https://www.ncbi.nlm.nih.gov/pubmed/34451610
http://dx.doi.org/10.3390/plants10081565
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author Trigiano, Robert N.
Boggess, Sarah L.
Wyman, Christopher R
Hadziabdic, Denita
Wilson, Sandra
author_facet Trigiano, Robert N.
Boggess, Sarah L.
Wyman, Christopher R
Hadziabdic, Denita
Wilson, Sandra
author_sort Trigiano, Robert N.
collection PubMed
description Helianthus verticillatus Small, the whorled sunflower, is a perennial species only found at a few sites in the southeastern United States and was declared federally (USA) endangered in 2014. The species spreads locally via rhizomes and can produce copious seeds when sexually compatible genotypes are present. Vegetative propagation of the species via cuttings and the optimum conditions for seed germination have not been determined. To investigate asexual propagation via cuttings, stem sections were harvested in late May, June, and July in Knoxville, Tennessee (USA) and trimmed to a minimum of two nodes. The base of the cuttings was treated with either auxin or water, and grown in a Promix BX potting medium with intermittent mist and 50% shade for one month. Seeds were harvested from a population of multiple genotypes in Maryville, Tennessee and used to determine viability and the range of temperatures suitable for germination. A clonal population was developed and used for three years to assess sexual compatibility at three locations in Knoxville, Tennessee. Ninety-five percent of the cuttings from May rooted in two-to-three weeks and formed more than 20 adventitious roots per cutting with auxin and 18 with water treatments. The ability of cuttings to root decreased in June to about 20%, and none rooted in July with either water or auxin pretreatments. Pre-germination tetrazolium tests indicated that about 91% of seeds (achenes) were viable. Subsequent germination tests revealed high germination at varying temperatures (96 to 99% of seeds (achenes) germinated at 22/11, 27/15, and 29/19 °C), whereas germination was significantly inhibited by 33/24 °C. Fifty percent of the seeds germinated at 22/11 °C in 7.5 days, whereas only 2.0 to 2.5 days were required for 50% germination at 27/15, 29/19, and 33/24 °C. Seeds were not produced at any of the clonal planting locations during the three years. Vegetative propagation via rooted cuttings was successful in the mid-spring, seed germination was possible over a wide range of temperatures, and self-incompatibility was evident in this species. The results of this study will permit fast and efficient propagation of multiple and selected genotypes for conservation, commerce, and breeding of elite cultivars with disease resistance or other desirable attributes.
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spelling pubmed-83996362021-08-29 Propagation Methods for the Conservation and Preservation of the Endangered Whorled Sunflower (Helianthus verticillatus) Trigiano, Robert N. Boggess, Sarah L. Wyman, Christopher R Hadziabdic, Denita Wilson, Sandra Plants (Basel) Article Helianthus verticillatus Small, the whorled sunflower, is a perennial species only found at a few sites in the southeastern United States and was declared federally (USA) endangered in 2014. The species spreads locally via rhizomes and can produce copious seeds when sexually compatible genotypes are present. Vegetative propagation of the species via cuttings and the optimum conditions for seed germination have not been determined. To investigate asexual propagation via cuttings, stem sections were harvested in late May, June, and July in Knoxville, Tennessee (USA) and trimmed to a minimum of two nodes. The base of the cuttings was treated with either auxin or water, and grown in a Promix BX potting medium with intermittent mist and 50% shade for one month. Seeds were harvested from a population of multiple genotypes in Maryville, Tennessee and used to determine viability and the range of temperatures suitable for germination. A clonal population was developed and used for three years to assess sexual compatibility at three locations in Knoxville, Tennessee. Ninety-five percent of the cuttings from May rooted in two-to-three weeks and formed more than 20 adventitious roots per cutting with auxin and 18 with water treatments. The ability of cuttings to root decreased in June to about 20%, and none rooted in July with either water or auxin pretreatments. Pre-germination tetrazolium tests indicated that about 91% of seeds (achenes) were viable. Subsequent germination tests revealed high germination at varying temperatures (96 to 99% of seeds (achenes) germinated at 22/11, 27/15, and 29/19 °C), whereas germination was significantly inhibited by 33/24 °C. Fifty percent of the seeds germinated at 22/11 °C in 7.5 days, whereas only 2.0 to 2.5 days were required for 50% germination at 27/15, 29/19, and 33/24 °C. Seeds were not produced at any of the clonal planting locations during the three years. Vegetative propagation via rooted cuttings was successful in the mid-spring, seed germination was possible over a wide range of temperatures, and self-incompatibility was evident in this species. The results of this study will permit fast and efficient propagation of multiple and selected genotypes for conservation, commerce, and breeding of elite cultivars with disease resistance or other desirable attributes. MDPI 2021-07-30 /pmc/articles/PMC8399636/ /pubmed/34451610 http://dx.doi.org/10.3390/plants10081565 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Trigiano, Robert N.
Boggess, Sarah L.
Wyman, Christopher R
Hadziabdic, Denita
Wilson, Sandra
Propagation Methods for the Conservation and Preservation of the Endangered Whorled Sunflower (Helianthus verticillatus)
title Propagation Methods for the Conservation and Preservation of the Endangered Whorled Sunflower (Helianthus verticillatus)
title_full Propagation Methods for the Conservation and Preservation of the Endangered Whorled Sunflower (Helianthus verticillatus)
title_fullStr Propagation Methods for the Conservation and Preservation of the Endangered Whorled Sunflower (Helianthus verticillatus)
title_full_unstemmed Propagation Methods for the Conservation and Preservation of the Endangered Whorled Sunflower (Helianthus verticillatus)
title_short Propagation Methods for the Conservation and Preservation of the Endangered Whorled Sunflower (Helianthus verticillatus)
title_sort propagation methods for the conservation and preservation of the endangered whorled sunflower (helianthus verticillatus)
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8399636/
https://www.ncbi.nlm.nih.gov/pubmed/34451610
http://dx.doi.org/10.3390/plants10081565
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