Molecular studies of Iranian populations support the morphology-based taxonomic separation of Medicago rigidula and M. rigiduloides

A comprehensive study was undertaken to understand the genetic status and help to clarify the division of Medicago rigidula (largely European) and Medicago rigiduloides (largely Asian). Genetic diversity parameters collectively suggested a low genetic diversity (avg. Ho, 0.073; He, 0.374) accompanied by high population differentiation (avg. F, 0.832; Gst, 0.362). Structure analysis divided 71 individuals (14 Iranian populations) into two highly distinct genetic groups (K=2) with significant genetic homogeneity. It also indicated the strong effect of the selfing mating-system as the main reason for the genetic diversity status and population structure. The population grouping was strongly confirmed by various clustering methods. Populations from north and northwestern Iran made up a distinctive genetic group corresponding to M. rigidula while the second group corresponding to M. rigiduloides harboured the western and two of the northwestern populations. The outcomes of this study provide the first reliable molecular evidence supporting the M. rigidula-M. rigiduloides separation previously suggested by morphology.

Germination success under different treatments and pod sowing depths in six legume species present in olive groves

This study analysed the germination success of pods of six annual native legumes species: Astragalus hamosus, Medicago minima, Medicago orbicularis, Medicago polymorpha, Medicago rigidula and Scorpiurus muricatus. The use of these species has been proposed as a means of generating and improving herbaceous cover in olive groves. Germination success was studied in terms of the variability in the number of seeds germinated per pod after 18 months at two different sowing depths, on the surface (S) and buried 10 mm (B). Pods were subject to five different pre-germination treatments: chemical scarification, consisting of immersion in sulphuric acid for 15 min (S_15) and 20 min (S_20), immersion in water for 48 h (W_48), pod precooled to -18ºC for one month (P_18º) and untreated pods (Con). The results showed that the effectiveness of the different treatments and sowing depths depended on the species, and that there were no problems of ‘sibling-competition’ in any of the treatments or at any of the sowing depths. Species with larger, non-spiralled pods, such as A. hamosus or S. muricatus, or with very loosely spiralled pods such as M. orbicularis, had greater germination rates when buried, mainly in the case of untreated pods and pods that were immersed in sulphuric acid for 20 minutes.

Sand-Dune Vegetation of Igneada Coast in the Thracian Part of Turkey

Sand-Dune Vegetation of Igneada Coast in the Thracian Part of TurkeyIgneada is located in the northwest part of Turkey on the Black Sea coast and it is also near the national border between Turkey and Bulgaria. The Igneada region was accepted as one of the most important plant areas of Turkey. In this work, a study was made on the phytosociological structure of Igneada sand dune vegetation, which is the one of the important components of the richness in the region. At the end of the assessment of the data, 3 communities were defined. These communities areOtantho-Leymetum sabulosi, Medicago rigidula-Cionura erectabasal community and meadow behind the sand dune. The part of the sand dune closest to the sea has width of 30 m, ascends with a specific inclination and has no vegetation coverage. Behind this part,Otantho-Leymetum sabulosioccurs at places where the sand dune has an unstable structure. TheMedicago rigidula-Cionura erectabasal community appears behindOtantho-Leymetum sabulosiand the sand dune has a stable structure at these areas. Behind these communities, another vegetation belt occurs, formed by the species that are cosmopolite or characteristic for meadow vegetation.

Seed yield and hardseededness of two amphicarpic pasture legumes (Vicia sativa ssp. amphicarpa and Lathyrus ciliolatus) and two annual medics (Medicago rigidula and M. noeana)

SUMMARYYields and hardseed breakdown of underground and aerial seeds in subterranean vetch (Vicia sativa ssp. amphicarpa) and lathyrus (Lathyrus ciliolatus) and aerial seeds of Medicago rigidula and M. noeana were compared at Tel Hadya, near Aleppo, in north Syria between 1990 and 1992. Underground and aerial seed and straw (mature herbage) yields were measured at maturity in the first spring, and hardseed breakdown over the following summer, autumn and winter. Regenerating herbage production was measured in the second spring.In the establishment year (292 mm rainfall) the medics produced twice as much straw as the amphicarpic species. In contrast, seed yields were less than half: M. rigidula and M. noeana produced 412 and 110 kg/ha respectively, while subterranean vetch and lathyrus produced 1174 and 736 kg/ha. More than 95 % of the total seed yield of the amphicarpic legumes was underground. Underground seeds of the amphicarpic legumes were larger than aerial seeds, and almost 10 times as large as the medic seeds.Seeds of all species were > 90% hard when newly set in summer. At the first seasonal rains > 95% of underground seed had softened, compared with 5 and 40% of the aerial seeds of vetch and lathyrus respectively. The medics remained > 90% hardseeded. In laboratory tests, embryo dormancy was observed in all species prior to the onset of first seasonal rains. For the amphicarpic legumes, but not for the medics, embryo dormancy persisted into winter. In the field, and after all germination events, 900–1430 seeds/m2 of subterranean vetch seed remained in the soil. This was considerably more than expected, based on the low levels of hardseededness and embryo dormancy observed in the laboratory. The results suggest that dormant seeds of the amphicarpic legumes need light to germinate.In the second year (353 mm rainfall), regenerating M. rigidula produced 5·3 t/ha compared with 3·4 t/ha by the best subterranean vetch from approximately equal numbers of seedlings. The amphicarpic legumes germinated later and over a more extended period than the medics, indicating that they could become weeds in a cereal/pasture rotation. However, the results suggest that in drier areas or in drier years the vetches will compare favourably with the medics in most respects. Clearly, subterranean vetch and lathyrus have great potential for pasture improvement in dry areas.

Prospects for Improving Mediterranean Grasslands in Lebanon through Seeding, Fertilization and Protection from Grazing

SUMMARYGrassland productivity was studied for four years near Terbol, Lebanon. In the first year pasture availability and plant numbers were monitored along transects, and in the following three years the effects of sowing four Mediterranean annual legumes (three cultivars of subterranean clover and a local ecotype of Medicago rigidula) and top-dressing with super-phosphate were studied. The results indicated that natural grasslands were dominated by annual grasses (Aegilops, Hordeum, Bromur, Lolium and Poa). Legume density was low, which resulted in poor legume productivity, especially in winter. Exotic legumes only resulted in a slight improvement in pasture productivity even when phosphate fertilizer was added. However, partial protection from grazing (for one or two months in late winter and spring) more than doubled the number of legume seeds in the seed bank compared with full protection and open grazing. The build up of seeds in the soil is an essential step towards the improvement of productivity in these degraded pastures, which form a large part of the land surface in Lebanon and on which small ruminant production largely depends.