Previous PageTable Of ContentsNext Page

Tolerance to salinity in some species of trifolium and medicago

I. Kaehne, E.T. Kobelt and B.M. Martin

Department of Agriculture, Northfield Research Laboratories GPO Box 1671, Adelaide SA 5001

Summary. The tolerance to salinity of 26 clover populations from 16 species of Trifolium, 32 lucerne and annual medic populations from 12 species of Medicago and one representative each of Hedysarum coronarium, Lotus corniculatus and Vicia villosa was assessed on plants grown from four weeks of age in a saline solution. The saline treatment was applied in intermittently flooded beds. NaCI concentration was increased from 40 to 220 mM/L over four weeks and then maintained. Tolerance was assessed by visual appearance and plant height. Trifolium species were generally more tolerant to intermittent hourly flooding and salinity than were Medicago species. Possible sources of tolerance to salinity in Trifolium and Medicago are indicated.


Salinity is a significant constraint to dryland and irrigated agriculture in Australia (2). Although salt tolerant grasses are well recognised and commercially used, there are no cultivars of pasture legumes recognised for their high tolerance. This study aimed to evaluate the salt tolerance under simulated poorly drained field conditions of an array of annual and perennial clovers and medics which have agronomic value in Australia.


Two experiments were conducted to determine the tolerances of populations of Trifolium and Medicago. Single check entries of Lotus, I ledysarum and Vicia were also included to give a comparison with the clovers and medics. Lotus is regarded as salt tolerant, Vicia villosa is not. The populations are listed in Tables 1 and 2. All cultivars tested are indicated. The arrays of M. polymorpha (A to H) and M. sativa (A to E) were progenies of saline-tolerant selections.

The populations were established in free-draining trays of loam-based and adequately fertilized potting mix approximately 8 cm deep. Each plot was a 25 cm row containing approximately 30 established seedlings. There were three replicates. At four weeks intermittent hourly flooding of the trays to 2 cm above their base was commenced with non-saline (control) and saline water in flooding bays. The NaCI concentration was increased from 40 to 220 mM/L over four weeks in six steps of 30 mM/L each and then maintained. This system of imposing the solution treatments was chosen to cause a partial waterlogging effect by capillary action above free water level in the flooding bays. This simulated the common association between saline conditions and partial or complete waterlogging in the field resulting from discharge of subsoil water or collection of saline runoff. Six weeks after the commencement of the intermittent flooding and saline treatments, tolerance was assessed using a rating for appearance and measuring stem length. The predominant colour of leaves was used for rating. Healthy leaves were rated 9, light-green leaves 7, yellow-green leaves 5, pale leaves with no green tone 3 and dead plants 0. If variation occurred in a plot a mean rating was estimated.

Results and discussion

The appearance ratings and stem lengths after six weeks of saline treatment for each population are presented in Tables 1 and 2 for the Trifolium and Medicago groups respectively.

Intermittent flooding with non-saline water had a moderate effect on the appearance of most Trifolium populations and Lotus. Only T. alexandrinum and T. scutatum were very poorly adapted. In contrast, many Medicago species and Vicia were severely affected by intermittent flooding only. The effect of flooding on Hedysarum was intermediate.

Table 1. The appearance rating and stem length of Trifolium populations after six weeks in saline and non-saline conditions.

Table 2. The appearance rating and stem length of annual and perennial Medicago populations after six weeks in saline and non-saline conditions.

The saline treatment imposed with intermittent flooding did not significantly reduce further the appearance rating of T. balansae, fragiferum, some T. isthmocarpum populations, T. nigrencens, T. repens, T. resupinatum or Lotus corniculatus, but reduced the stem length of all Trifolium populations. Their appearance rating ( 7) suggests that selection should be possible for both tolerance to salinity and adaptation to poorly drained soil conditions in many Trifolium species. Lotus corniculatus was tolerant to salinity but Hedysarum coronarium and Vicia villosa were intolerant.

In the Medicago lines, the saline treatment imposed with intermittent flooding further reduced plant appearance and also reduced stem length except in M. intertexta (B) and M. murex cv. Zodiac. Some individual plants of M . intertexta, M . murex and M. polymorpha set pods and seed when allowed to grow on in the saline solution beyond evaluation at 10 weeks of age. Polymorphism for tolerance to partially waterlogged saline conditions may occur in many accessions of these species. The progenies of M. polymorpha from saline sites were not tolerant to intermittent flooding and salinity except population D which expressed marginal tolerance.

Although some lucerne, M. sativa, genotypes are salt-tolerant in freely drained conditions (1) no tolerant individual plants were identified in this experiment, even in populations A to E which were progenies of field selections from saline sites. The salinity tolerance per se of these populations may have been masked by their sensitivity to intermittent flooding. Interspecific hybridization of M. sativa with other annual species (3) may be a rewarding path to achieve a perennial medic with adaptation to saline poorly-drained soils. It is unlikely that selection within M. sativa will achieve development of a salt tolerant perennial to control rising saline water tables.


This experiment was supported by the Wool Research and Development Council. The noncommercial lines of M. saliva (A to E) were developed by the South Australian Department of Agriculture and of M. polymorpha (D to H), were collected by E.T. Kobelt in saline sites. All other non-commercial entries were supplied by G.C. Auricht from the SA Genetic Resources Unit.


1. Noble C.L., Halloran, G.M. and West, D.W. 1984. Aust. J. Agric. Res. 35, 239-252.

2. Standing Committee on Soil Conservation, 1982. Salting of Non-irrigated Land in Australia. (Soil Conservation Authority: Victoria).

3. Thomas, M.R., Johnson, L.B. and White, F.F. 1990. Plant Science 69, 189-198.

Previous PageTop Of PageNext Page