Genetic diversity of alfalfa (Medicago sativa) in response to temperature during germination

Temperature is one of the major factors controlling plant development, in particular seed germination. Alfalfa is a perennial pasture legume that holds an important place in cultivated grasslands. Breeding alfalfa cultivars adapted to new ranges of temperature could be necessary, requiring knowledge of the variability in response to temperature among different accessions. Six accessions of Medicago sativa subsp.sativa and one wild population of M. sativa subsp. falcata were evaluated for their germination temperature response. Seeds were tested for germination in the dark at eight constant temperatures, from 5 to 40°C. Significant differences (P < 0.01) were found. The optimum temperature for germination ranged between 11.7 and 21.1°C, whereas two varieties, 'Demnate' and 'Luzelle' had a very wide range of temperatures favouring maximum germination. The findings of this study suggest that the germination of alfalfa was little affected by low temperature (5°C) whereas germination at 40°C was lower and showed high variability. Our results revealed variability in the response to temperature for germination of M. sativa that gives room for breeding new varieties adapted to future environmental conditions induced by the global climate change.