Medicago sativa species complex: Revisiting the century‐old problem in the light of molecular tools

Abstract

The genus Medicago is an important component of legumes and includes the model legume barrel‐clover (Medicago truncatula Gaertn.) and widely cultivated forage crop alfalfa (M. sativa L.). The complex taxonomic group known as the M. sativa species complex, or M. sativa–falcata species complex, includes a number of taxa along with cultivated alfalfa that naturally distributed throughout northern Eurasia. Largely because of the millennia‐long economic importance, the taxa have been in the center of attention. In the context of the efforts to understand taxonomic units included in the complex, a wide range of tools have been exploited. The early tools available were morphological traits such as flower color, pod shape, and pollen shape. The large conflict and discrepancy among researchers regarding the statue of the taxa sourced from the fact that a few genes controlled each of the morphological traits used. Thus, the morphology‐based classification was proved to be contradictory. As the molecular tools became available and the research intensified, the initial species status generously granted to the taxa was questioned, and all the taxa denoted as species earlier were relegated to subspecific level. We are aiming to provide an up‐to‐date comprehensive picture for the complex in the light of recent molecular studies.

Phenotypic Diversity and Productivity of Medicago sativa Subspecies from Drought-Prone Environments in Mediterranean Type Climates

“…This work confirms the existence of a broad phenotypic diversity among accessions of the M. sativa-falcata complex [ 11 , 12 , 14 , 21 , 22 , 23 , 24 ], but it also adds new evidence of the genetic contribution of alfalfa wild relatives for improving agronomic performance of cultivated alfalfa in Mediterranean drought-prone environments. Furthermore, new insights about the outstanding genetic contribution of Medicago arborea to the M. sativa-falcata complex were observed at field condition in pre-bred lines.…”

“…All these modifications could be considered as water saving physiological mechanisms. In this work, accessions belonging to varia and alborea exhibited higher values of SLA, which would support the putative drought tolerance associated with these two subspecies [10,14,17,18]. Accessions with higher values of SLA (344 cm 2 g −1 , in average) were landraces APG58574 (varia), APG40234 (sativa), and Altasierra5 (sativa); pre-bred lines CTA011, CTA008, CTA004 (varia), and CTA002 (alborea); cultivars Zhungeer (varia) and Genesis (sativa).…”

“…A large body of literature supports the abundant genetic diversity within the M. sativa-falcata complex [ 10 , 11 , 13 , 14 , 22 , 23 , 24 , 26 , 28 ]. However, genetic diversity used for breeding has been mostly based on cultivated populations.…”

“…x varia (4n), and M. sativa subsp. glomerata (4n) [ 14 ]. These subspecies represent the primary gene pool for alfalfa improvement [ 10 , 11 , 14 ].…”

“…glomerata (4n) [ 14 ]. These subspecies represent the primary gene pool for alfalfa improvement [ 10 , 11 , 14 ]. Recently, Humphries et al [ 10 ] pointed out that primary gene pool offers great potential for alfalfa drought tolerance improvement.…”