Submitted to: American Peanut Research and Education Society Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: July 11, 1996
Publication Date: N/A
Technical Abstract: Use of mature dried seed as an effective, convenient explant source for somatic embryogenesis has been reported for peanut lines grown in the Southeast. Few embryogenic systems have been reported that are capable of producing a repetitively embryogenic culture, critical for stable genetic transformation via microprojectile bombardment. We report on production of fstable, continuously embryogenic tissue cultures of peanut cultivars grown in the Southwest. Mature, dry zygotic embryo axes of Okrun were cultured on MS medium containing 4 concentrations each of 2,4-D, PBA, 2,4,5-T, and picloram. Somatic embryos (SEs) were produced on all growth regulators except PBA. 2,4-D required a higher concentration for activity than picloram or 2,4,5-T. After 4-wk exposure to plant growth regulators, embryo axes responded differently to various treatments: 90% responded to >10uM 2,4-D, 70% responded to >1uM 2,4,5-T, 87% responded to >1uM picloram. SE germination and plant recovery were significantly greater with 2,4-D than other plant growth regulators. On solidified medium, repetitively embryogenic cultures were produced via picloram and 2,4,5-T, but stable long-term cultures were only obtained via picloram exposure. Axes cultured on 2um picloram showed significant differences in embryogenic response between cultivars. Although >83% of explants from all cultivars produced at least 1 SE, NC-7 produced twice as many as Okrun or TS90. Okrun and TS90 produced more than twice as many as Southwest Runner. Interestingly, embryogenic callus production was significantly elevated in cultivars with Spanish parentage. Okrun is preferred for long-term repetitive cultures and microprojectile bombardment, due to stability of SE quality, reduced callus production, and high degree of SE proliferation.