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Genome-wide variation in and between two closely related underutilised horsegram species (Macrotyloma axillare and M. uniflorum, Fabaceae)

Genome-wide variation in and between two closely related underutilised horsegram species (Macrotyloma axillare and M. uniflorum, Fabaceae)
Genome-wide variation in and between two closely related underutilised horsegram species (Macrotyloma axillare and M. uniflorum, Fabaceae)

The assessment of the degree and partitioning of genetic variation in crop populations and species is crucial to understand their adaptive evolution and provides vital knowledge to assist in the development of crops to combat food insecurity. Underutilised crops are understudied but are often drought-/heat-tolerant or nutritionally diverse; hence, as food security becomes more pressing, their investigations are increasing. Here, we focus on horsegram (Macrotyloma uniflorum (Lam.) Verdc.) and perennial horsegram (M. axillare (Meyer) Verdcourt), two closely related drought- and heat-tolerant underutilised legumes. Forty-two accessions were studied through phylogenetic and population genetic analysis and by measuring their seed and plant morphologies to assess genetic and morphological variation within and between the species. The species were distinct at the genetic level, with genetic diversity about 2.5 times greater in M. axillare than in M. uniflorum. Previously unsampled horsegram accessions from Africa were distinct from South Asia and therefore could contain novel genetic variation. Genetic variation suggested four clusters within perennial horsegram, which were largely structured by geography. Seed length is significantly greater in horsegram, and the two species differ in their dominant seed and stem colours, which could assist in-field identification. This work provides new insight into these species specifically and underutilised legumes more generally. Future investigations focused on identifying adaptive genetic variation are warranted to further reveal the potential of these crops in being optimized for promotion and commercialization, especially in countries which need more sustainable and reliable agricultural varieties to mitigate climate change.

Macrotyloma, horsegram, genetic variation, underutilised crop
2041-2851
Taylor, Niall P.
47e93b67-abe0-4662-9ce9-b383a4b216d3
Chapman, Mark A.
8bac4a92-bfa7-4c3c-af29-9af852ef6383
Taylor, Niall P.
47e93b67-abe0-4662-9ce9-b383a4b216d3
Chapman, Mark A.
8bac4a92-bfa7-4c3c-af29-9af852ef6383

Taylor, Niall P. and Chapman, Mark A. (2026) Genome-wide variation in and between two closely related underutilised horsegram species (Macrotyloma axillare and M. uniflorum, Fabaceae). AoB PLANTS, 18 (1), [plag003]. (doi:10.1093/aobpla/plag003).

Record type: Article

Abstract

The assessment of the degree and partitioning of genetic variation in crop populations and species is crucial to understand their adaptive evolution and provides vital knowledge to assist in the development of crops to combat food insecurity. Underutilised crops are understudied but are often drought-/heat-tolerant or nutritionally diverse; hence, as food security becomes more pressing, their investigations are increasing. Here, we focus on horsegram (Macrotyloma uniflorum (Lam.) Verdc.) and perennial horsegram (M. axillare (Meyer) Verdcourt), two closely related drought- and heat-tolerant underutilised legumes. Forty-two accessions were studied through phylogenetic and population genetic analysis and by measuring their seed and plant morphologies to assess genetic and morphological variation within and between the species. The species were distinct at the genetic level, with genetic diversity about 2.5 times greater in M. axillare than in M. uniflorum. Previously unsampled horsegram accessions from Africa were distinct from South Asia and therefore could contain novel genetic variation. Genetic variation suggested four clusters within perennial horsegram, which were largely structured by geography. Seed length is significantly greater in horsegram, and the two species differ in their dominant seed and stem colours, which could assist in-field identification. This work provides new insight into these species specifically and underutilised legumes more generally. Future investigations focused on identifying adaptive genetic variation are warranted to further reveal the potential of these crops in being optimized for promotion and commercialization, especially in countries which need more sustainable and reliable agricultural varieties to mitigate climate change.

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More information

Accepted/In Press date: 16 December 2025
e-pub ahead of print date: 16 January 2026
Published date: 11 February 2026
Keywords: Macrotyloma, horsegram, genetic variation, underutilised crop

Identifiers

Local EPrints ID: 511863
URI: http://eprints.soton.ac.uk/id/eprint/511863
ISSN: 2041-2851
PURE UUID: a7f82661-f37c-4fca-8851-fc64cab63c18
ORCID for Mark A. Chapman: ORCID iD orcid.org/0000-0002-7151-723X

Catalogue record

Date deposited: 08 Jun 2026 16:44
Last modified: 09 Jun 2026 01:45

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Contributors

Author: Niall P. Taylor
Author: Mark A. Chapman ORCID iD

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