Selection of alfalfa (Medicago sativa L.) cultivars for salt stress tolerance using germination indices

To select the most tolerant alfalfa genotypes to salinity stress, an experiment was performed in a factorial scheme having a completely randomized design (CRD) with three replications. The cultivar and salinity stress factors comprised 20 cultivars and four levels of salinity stress (control, 75, 150 and 225 mM) with NaCl, respectively. Results indicate that a significant decrease was observed in all traits except for mean germination time in stress conditions. The Bami Garmsiri cultivar showed the highest germination percentage, germination rate, radicle length, plumule length, seedling length, radicle length/plumule length ratio and seed vigour traits in salinity conditions. Results of the cluster analysis using the data for all measured traits and salinity levels clustered cultivars into two groups. Cultivars KFA 1 , KFA 5 , KFA 12 , KFA 16 , Yazdii Garmsiri, KFA 2 , KFA 4 , KFA 11 , Nikshahri Garmsiri and Bami Garmsiri as well as KFA 3 , KFA 6 , KFA 7 , KFA 9 , KFA 17 , KFA 8 , KFA 13 , KFA 10 , KFA 14 and KFA 15 were placed in the first and second clusters, respectively. Cultivars in the first cluster were found to be tolerant, while those in the second cluster were sensitive to salt. Bami Garmsiri was the most tolerant cultivar to salt. However, all the cultivars were used in large field trials to confirm their tolerance to salt waiting creation of new hybrid varieties.