Genet Resour Crop Evol (2020) 67:875–894 https://doi.org/10.1007/s10722-020-00886-8 (0123456789().,-volV)( 0123456789().,-volV) RESEARCH ARTICLE Diversity of grasses (Poaceae) in southern Africa, with emphasis on the conservation of pasture genetic resources M. Trytsman . F. L. Mu¨ller . A. E. van Wyk Received: 12 June 2019 / Accepted: 16 January 2020 / Published online: 6 February 2020 Ó Springer Nature B.V. 2020 Abstract A renewed interest in the present state of and 685 species, inferring that only 20% of the world’s genebanks conserving pasture genetic resources grass genera and 6% of world’s grass species are found worldwide motivated this study to quantify the wealth in the study area with Panicoideae the most speciose of grass (Poaceae) diversity indigenous to southern subfamily. Paniceae is the only tribe with large Africa, here defined as South Africa, Lesotho and numbers of both C3 and C4 species and with several Eswatini (previously Swaziland). Botanical occur- species of high grazing value, therefore, was suggested rence records were extracted from BODATSA and as a priority lineage in the collection and conservation PHYTOBAS datasets to generate a list of grass species efforts of the South African National Forage Gene- indigenous to the study area. The phylogenetic bank. This genebank conserves at present 73 genera classification, growth form, photosynthetic pathway, and 162 indigenous grass species, i.e. 48% and 24% of grazing status, endemism and conservational status the total number of taxa respectively, denoting the attributes were added to the 43,889 species level current vulnerable status of grass genetic resources in records, sourced from published literature. Results southern Africa. A need to therefore collect and from the current study indicate that the subcontinent is conserve grass genetic resources is emphasised, with represented by eight subfamilies, 25 tribes, 151 genera greater focus on the conservation of seed of well- known pasture genera classified as endangered or possibly extinct (mainly Panicum L. and Secale L.). Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10722-020-00886-8) con- Keywords Endemism Á Eswatini Á Gramineae Á tains supplementary material, which is available to authorized Lesotho Á South Africa users. M. Trytsman (&) Á F. L. Mu¨ller Agricultural Research Council-Animal Production Institute, Lynn East, PB X05, Pretoria 0039, South Africa Introduction e-mail: [email protected] A. E. van Wyk Poaceae (Gramineae), the members of which are Department of Plant and Soil Sciences, University of commonly referred to as grasses and bamboos, is Pretoria, Pretoria 0002, South Africa considered as probably the most valuable plant family to humankind (Bouchenak-Khelladi et al. 2010). The A. E. van Wyk National Herbarium, South African National Biodiversity family includes the economically important cereals, Institute, Pretoria 0001, South Africa 123 876 Genet Resour Crop Evol (2020) 67:875–894 sugar crops, reeds, bamboos, forages and lawn grasses The decline in the pasture breeding capacity in (Hodkinson 2018). The success of this family can be South Africa (Truter et al. 2015) has resulted in many attributed to, amongst others, its adaptability to most of these species not being characterised and evaluated ecosystems, including arctic regions and at high for their pasture potential. Therefore, due to the lack of elevations uninhabitable by flowering plants (Tzvelev information regarding their pasture potential these 1989), ecological dominance in many ecosystems, and species have not yet been included in breeding and high species richness (Linder et al. 2018). evaluation programs. These plant genetic resources The important role of the Poaceae in sustainable are, however, still important sources of genetic livestock production is well known, with several material that could, under future bioclimatic condi- genera housing important pasture species (Truter et al. tions become valuable resources for breeding of future 2015; Capstaff and Miller 2018). The exploration of pasture species adapted to specific agro-ecological the potential of southern African grasses for pastures conditions. As a result, these plant genetic resources began as early as the 1900s, with the past 50 years are maintained in perpetuity at the SA-NFG as a means described as a period where the function and value of to maintain the plant genetic diversity that could southern African grasses were studied by several potentially be beneficial under future bioclimatic pasture researchers (Truter et al. 2015). An important conditions. Maintaining and conserving these plant initiative towards the conservation of grass genetic genetic resources however, puts significant financial resources in southern Africa was a collection excur- pressure on the SA-NFG. Recently, Pengelly and sion specially arranged for this purpose, to the Kruger Maass (2019) and Maass and Pengelly (2019) called National Park in South Africa, during the early 1990s. for the prioritization of germplasm as well as to This ensured that selected ecotypes of important improve the efficiency in conserving current collec- pasture species such as Anthephora pubescens Nees, tions of plant genetic resources housed at genebanks Cenchrus ciliaris L., Chloris gayana Kunth, Cynodon across the globe. This, in turn, is believed to reduce the dactylon (L.) Pers., Digitaria eriantha Steud., Era- financial burdens on genebanks, by shifting efforts to grostis curvula (Schrad.) Nees and Panicum maximum only priority species, and locally adapted varieties and Jacq. were conserved in the South African National ecotypes within important pasture species with known Forage Genebank (SA-NFG) (Kruger et al. 1993). agronomic potential (Pengelly and Maass 2019; Maass However, similar to trends in the international and Pengelly 2019). This will allow for the conserva- genebank community, especially those housing trop- tion of a larger genetic diversity within species with ical and sub-tropical plant genetic resources (Maass known agronomic potential, which, in turn, will and Pengelly 2019; Pengelly and Maass 2019), the benefit future breeding programs of these species. conservation of these plant genetic resources have An example of this can be found in domesticated been under threat for the last 20 years. Generally, the African grass species such as Sorghum bicolor (L.) funding to manage and maintain forage genebanks Moench and Pennisetum glaucum (L.) R.Br. that are around the globe is on the decrease, resulting in many currently maintained and conserved for at least two- important plant genetic resources potentially being thirds of their diversity of their wild relatives (Buckler lost (Maass and Pengelly 2019). In the case of the SA- et al. 2001). NFG, the plant genetic resources maintained at the Van Wyk (1995) emphasized that the recognition facility was mainly threatened by the lack of funding and interpretation of genetic variation in organisms is which resulted in unreliable storage and testing at the heart of taxonomy and called on plant facilities, coupled with a decline in trained personnel taxonomists in Africa for the urgent naming of capable of maintaining and evaluating the valuable infraspecific units. A striking example that highlighted collection of plant genetic resources housed at the the importance of this appeal was the revision of facility. Also, the SA-NFG houses a large number and Agrostis eriantha Hack. var. planifolia Goossens & diversity of plant genetic resources, many of which Papendorf being reduced to synonymy under A. eri- currently are perceived to have minimal to no antha Hack. (Victor et al. 2012). A method to agronomic potential due to the lack of information prioritize taxonomic revision of South African plant regarding their pasture potential. These species were genera was developed by Victor et al. (2015) to reduce collected with future breeding in mind. the taxonomy-conservation disorder where indicators 123 Genet Resour Crop Evol (2020) 67:875–894 877 such as revision dates, insufficient data (including diversity of indigenous grasses at tribe and species taxonomic uncertainty) and endemism were proposed level. Linking attributes such as photosynthetic path- as indicators. Furthermore, a literature review done in way, growth form and grazing status with phyloge- the early 1990s showed that only a few key or netic classification could assist in distinguishing taxa important indigenous grass species had complete with pasture potential. To ensure a similar outcome as autecological studies with the exception of Themeda for the pasture potential appraisal of legumes (Legu- triandra Forssk., Eragrostis curvula and Digitaria minosae/Fabaceae) indigenous to South Africa, eriantha (Shackleton 1991). A need for a coordinated, Lesotho and Eswatini (previously Swaziland) (Tryts- systematic approach in basic ecological research of man et al. 2016, 2019), this paper takes stock of the grass species in different biomes was therefore wealth of indigenous grass genetic resources with suggested. added references to grass species currently used in The most recent taxonomic review of genera in pasture systems. This, in turn, will help with efforts to southern African grasses was within the temperate prioritise conservation of important grass genetic genus Helictotrichon Besser s.l. (Mashau et al. 2010) resources at the SA-NFG, in line with the call by where two new species were identified. Germishuizen Maass and Pengelly (2019)