الفهرس 
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Abstract
The main objectives of this recent study, was to quantify salt- tolerance of eleven local and introduced alfalfa populations/cultivars, in terms of germination, early season growth and successive cutting responses. The recent study was carried out during the period between September, 2016 until September 2018. A diagonal diagram for soil sampling was made. Depending on soil analysis, the experimental site was divided to four strips with different soil salinity gradient. Strip 1, showed Ec values between 2.89 and 5.19 ds/m. Strip Π had salinity gradient between 4.89 and 7.02 ds/m. Strip III had Ec values between 6.76 and 9.23. Strip IV had salinity between 8.74 and 12.24 ds/m. The four major strips were considered as a gradient of soil salinity levels. Eleven genotypes of alfalfa ”Medicago sativa,L.” represented the available local and introduced population (Makka, Ramah1, Nubaria1, Siwa1, Siwa2, Frafra, Sohage, Sopsta, Siriver, Pakistani), were evaluated under each of the aforementioned soil salinity gradients in four separate experiments. In each experiment (Soil salinity level), the studied alfalfa genotypes were tested in a randomized completely block design of six replicates. Plot area was 2.4 m2, represented by three rows of four meters long, at 0.2 meter apart. Seeding rate was 60 Kg.hectar. Sowing date was mid- September, 2016. Mono superphosphate (15.5% P2O5 was added before sowing at the rate of 350 Kg.ha-1. Normal irrigation practices for alfalfa in EL-Tahrir area were applied. The first cutting was taken after 60 days from sowing. A field germination counts were taken after 7,14 and 21 days from sowing. A total of 17 cuttings were taken, the following characters were recorded. The obtained results might be summarized in the following: A. Field germination percentage:
1. Germination percentage over the evaluated populations, significantly differed from recording date to the other (P≥ 0.01) under all salinity gradient experiments (significant effect of recording date).
2. Also, the studied alfalfa populations gave significantly different field germination scores over recording dates in all four experiments (significant effect of population).
3. Meanwhile, the studied populations maintained similar magnitude and /or trend of germination percentage, irrespective of recording date(insignificant interaction between date× population).
4. Under the first experiment (salinity of 2.89-5.19 ds/m)germination percentage over populations increased proportional to the counting date from 49.85 to 52.05 to 64.70% for 7,14, and 21 days from sowing. Meanwhile, Makka, Rammah1 and Sohage populations, scored over 60% germination as an average over the three counting dates. The least germination percentage was recorded for Pakistani population which was 21.39% over the three counting dates.
5. The second salinity gradient (experiment2) (4.89-7.02 ds/m),showed lower germination percentage at the three successive recording dates (46.51, 50.99, and 58.33% after 7,14, and 21days from sowing). Only, Makka and Sohage populations had showed over recording dates an average germination percentage over 60%. The least average germination percentages were scored by Pakistani 65 population. Sopsta, population of European origin, showed an average less than 50% germination.