Variability of somatic embryogenic ability in the genus Pisum L: Effects of genotype, explant source and culture medium

The ability of shoot apices, immature cotyledons and embryonic axes excised from mature seeds to express somatic embryogenesis was tested in nine garden peas, eleven field peas, two forage peas and seven species or subspecies other than Pisum sativum L. Embryonic axes were poorly embryogenic when compared to the two other explants. Shoot apices and immature cotyledons were both cultured on two media differing in their sugar composition. Seven garden peas out of nine were more embryogenic than all the field peas. Many genotypes, 22 out of 29, produced more embryos in cultures of shoot apices when fructose substituted sucrose. With immature cotyledons, somatic embryogenesis was also enhanced for 20 genotypes out of 29 on maltose-supplemented medium compared to sucrose-containing medium. Thus, exogenous carbohydrate seemed to play an essential role in somatic embryogenesis in pea.