Eleusine

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Eleusine
Eleusine coracana

Eleusine coracana

Systematics
Class : Bedecktsamer (Magnoliopsida)
Monocots
Commelinids
Family : Sweet grasses (Poaceae)
Subfamily : Chloridoideae
Genre : Eleusine
Scientific name
Eleusine
Garden.

Eleusine is a genus of plants within the sweet grassfamily(Poaceae). The approximately ten species are distributed almost worldwide, with the main distribution in tropical Africa. The genus includes the grain type finger millet ( Eleusine coracana ) and with Eleusine indica a dreaded “ weed ”that is widespread worldwide today.

description

Illustration of Eleusine indica

Vegetative characteristics

In Eleusine TYPES is partly to one-year, partly to perennial herbaceous plants . They are usually clump-shaped grasses. Short and long internodes alternate on the stalk , causing the leaves to be heaped, sometimes seemingly opposite. The leaf blade is usually narrow, the ligule short, membranous and often ciliate.

Fruit stand of crabgrass

Generative characteristics

The inflorescence consists of several, finger-shaped ears (at the end of the stalk branched from one point) (rarely, exceptionally, only one), or this is clustered, but then almost finger-shaped at the end of the stalk. The spikelets are sessile on the abaxial side of the axis ( rachis ), lying obliquely upright against the rachis , mostly overlapping, they are laterally compressed. All husks are awnless. The glumes and lemmas are keeled, the keel of the lemma can be narrowly winged. The glumes are shorter than the spikelet, this is at least two- to three-flowered.

When the fruit ripens, the fruits ( caryopses ), with the exception of the cultivated plant Eleusine coracana , are released by breaking the spikelet spindle. The pericarp of the grains peel off easily, the grains are clearly marked on the surface by often warty structured horizontal stripes or quills.

Systematics

The genus Eleusine was established by Joseph Gärtner in 1788 . The name of the genus Eleusine goes back to the mysteries of Eleusis , which are associated with the goddesses Demeter and Persephone and thus with fertility, especially the cultivation of grain.

Species, distribution and their importance for humans

The genus includes about eight to ten species, depending on the definition and conception. Of these, the Eleusine indica weed is now carried around the world in tropical and subtropical latitudes and is a dreaded weed in agricultural crops everywhere, many populations of which are resistant to glyphosate and other herbicides. The grain type finger millet is one of the most important grains in tropical latitudes with a semi-arid climate, especially in Africa and India, but it is mainly grown in subsistence farming .

There are the following types:

Phylogeny and Genetics

The basic chromosome numbers in Eleusine species are x = 8, 9 or 10. While most species are diploid , three are allotetraploid, which means that they owe their origin to a hybridization between two closely related species, with a doubling of the chromosome set. Of Eleusine indica both diploid and tetraploid as populations are known. The finger millet belongs to the allotetraploid species, in addition to its presumed wild stem form Eleusine africana . While Eleusine indica (or its common ancestor with Eleusine tristachya ) could be identified as a presumed parent species , the other is controversial, possibly a species that is now extinct. The situation is further complicated by the fact that, especially in Africa, wild and Cultivars (especially land races ) still hybridize with one another today.

In phylogenomic analyzes (analysis of the relationship by comparing the sequences of homologous DNA sequences), the genus was found to be monophyletic . Species of the African genera Coelachyrum and Apochiton were identified as a sister group , a closer relationship with genera such as Acrachne and Dinebra , which was suspected on the basis of morphological characteristics, is not certain. With a number of similar genera, including the dog toothgrass ( Cynodon ), it belongs to a group that has been taken as the Subtribus Eleusininae. The American Eleusine tristachya is very closely related to the originally African and South Asian Eleusine indica , so that it is assumed that it could be traced back to a relatively recent, natural long-distance distribution of seeds across the Atlantic.

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Individual evidence

  1. ^ National Research Council (editor): Lost Crops of Africa. Volume I: Grains. Washington, DC, USA: National Academy Press, 1996.
  2. ↑ a b c d e f g h i Rafaël Govaerts (Ed.): Eleusine. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved November 18, 2016.
  3. ↑ L. Dagnachew, S. de Villiers, T. Sewalem, M. Dida, F. Masresha, W. Kimani, T. Kassahun: Genetic diversity and eco-geographic distribution of Eleusine species collected from Ethiopia. In: African Crop Science Journal , Volume 22, Issue 1, 2014, pp. 45–58.
  4. ↑ Paul M. Peterson, Konstantin Romaschenko, Yolanda Herrera Arrieta: A molecular phylogeny and classification of the Eleusininae with a new genus, Micrachne (Poaceae: Chloridoideae: Cynodonteae). In: Taxon , Volume 64, Issue 3, 2015, pp. 445–467. doi : 10.12705 / 643.5
  5. ↑ Qing Liu, Bin Jiang, Jun Wen, Paul Michael Peterson: Low-copy nuclear gene and McGISH resolves polyploid history of Eleusine coracana and morphological character evolution in Eleusine . In: Turkish Journal of Botany , Volume 38, 2014, pp. 1–12.

Web links

Commons : Eleusine  - collection of images, videos and audio files