Comparing Salt Tolerance at Seedling and Germination Stages in Local Populations of Medicago ciliaris L. to Medicago intertexta L. and Medicago scutellata L.

Salt stress is one of the most serious environmental stressors that affect productivity of salt-sensitive crops. Medicago ciliaris is an annual legume whose adaptation to agroclimatic conditions has not been well described. This study focused on the salinity tolerance of M. ciliaris genotypes compared to M. intertexta and M. scutellata in terms of plant growth, physiology, and biochemistry. Salt tolerance was determined at both germination and early seedling growth. Germination and hydroponic assays were used with exposing seeds to 0, 50, 100, 150, and 200 mM NaCl. Among seven genotypes of M. ciliaris studied, Pop1, 355, and 667, were most salt tolerant. Populations like 355 and 667 showed marked tolerance to salinity at both germination and seedling stages (TI ≤1, SI(FGP) > 0 increased FGP ≥ 20% and SI(DW) < 0 (DW decline ≤ 20%); at 100 mM); while Pop1 was the most salt tolerant one at seedling stages with (TI =1.79, SI(FGP) < 0 decline of FGP ≤ 40% and with increased DW to 79%); at 150 mM NaCl). The genotypes, 306, 773, and M. scutellata, were moderately tolerant to salt stress depending on salt concentration. Our study may be used as an efficient strategy to reveal genetic variation in response to salt stress. This approach allows selection for desirable traits, enabling more efficient applications in breeding methods to achieve stress-tolerant M. ciliaris populations.

Chloroplast genomic variation and phylogeny in Medicago section Intertextae

Restriction endonuclease analysis of chloroplast DNA (cpDNA) was conducted on Medicago ciliaris, Medicago intertexta, Medicago muricoleptis, and Medicago granadensis, which comprise section Intertextae of the genus Medicago. Numerical taxonomic analyses of cpDNA data by a variety of techniques indicated the same species relationships found in a previous study when these numerical analyses were applied to phenotypic and karyotypic characters. The correspondence between cpDNA, general morphology, and karyotypic data suggests that all data mirror general evolution. Data from this study support earlier proposals of a close relationship between Medicago ciliaris and Medicago intertexta, with these species evolving from a common lineage and a later, independent evolution of Medicago muricoleptis and Medicago granadensis from Medicago intertexta.