Chromosome number, genome size, seed storage protein profile and competence for direct somatic embryo formation in Algerian annual Medicago species

Abstract

The genome size of eight species from different wild Algerian populations of diploid and one tetraploid Medicago L., initially analysed for chromosome numbers and seed storage proteins, has been assessed by flow cytometry. Genome size ranged from 2C = 0.94 pg in Medicago orbicularis (L.) Bartal. to 2C = 1.80 pg in Medicago laciniata (L.) Miller. The competence for direct somatic embryo formation in liquid medium was studied for 4 of these species having distinct genome sizes: M. orbicularis (2C = 0.94 pg); M. truncatula Gaertn. (2C = 1.08 pg); M. scutellata (L.) Miller (2C = 1.11 pg); M. arabica (L.) Huds. (2C = 1.22 pg). M. orbicularis, with the smallest genome size, formed somatic embryos most quickly, with a high frequency of reactive explants and with numerous somatic embryos per explant. It was followed by M. truncatula, M. scutellata and M. arabica, which in fact represents the order of increasing genome size.