HIGH-FREQUENCY SOMATIC EMBRYOGENESIS IN PEANUT (ARACHIS-HYPOGAEA L) USING MATURE, DRY SEED

Peanut (Arachis hypogaea L.) somatic embryos were produced from the em bryo axes of mature, dry seeds of cultivar GK-7. Percent embryogenic e xplants ranged from 88-100% using 10-40 mg/l of 2,4-D in the induction medium. Neither 2,4-D concentration nor photoperiod during the induct ion period had a large effect on percent embryogenesis, mean number of embryos per explant, or embryo morphology. However, embryos obtained from cultures grown in the dark were easier to remove from the explant than those under a 16-h photoperiod. Somatic embryos developed on the epicotyl portion of the embryo axis, primarily on the young, expandin g leaves. A survey of 14 genotypes indicated that genotype had a large influence on embryogenic capacity, with all genotypes being embryogen ic to some extent. The ability to recover somatic embryos from axes of harvested, stored seeds represents significant advantages for the est ablishment of peanut embryogenic cultures, including the use of simple sterilization procedures and a constant source of explant tissue.