Abstract:
An efficient protocol for regenerating high yielding groundnut varieties; ICGV-CG2 and CG2
through direct organogenesis has been optimized using 6-benzylaminopurine and 2,4-
dichlorophenoxyacetic acid. Murashige and Skoog medium with B5 vitamins was supplemented with
individual treatments of BAP and 2,4-D and with their combinations to induce shoot bud formation.
Preliminary results showed no shoot formation on media with the individual plant growth regulators. The
highest and lowest regeneration frequencies in CG2 were 93.33% and 36.67% respectively on medium
supplemented with 1 mg/L 2,4-D and 4.5 mg/L BAP. In ICGV-CG2 the highest frequency was 90% on
media with 1.5 mg/L 2, 4-D and 4.5mg/L BAP with a low of 46.67%. Three (3) to ten (10) shoots were
recorded per explant, with a maximum of ten shoots recovered from the best performing plant growth
regulator regimes. Shoots elongated on MS with reduced BAP levels (0.75-4.5mg/L), rooted on media
with α-naphthalene acetic acid and later acclimatized in the glasshouse on peat moss. Hardening and
growth of plants to maturity was achieved in the glasshouse on a sand-soil mixture (1:1 w/w) in pots. In
vitro induction of flowers in one of the explants could have been as a result of somaclonal variation. This
work has developed an optimized protocol that sets up a platform for improvement of these varieties that
are adapted to East Africa with novel genes through genetic transformation
Keywords: Direct organogenesis; genotype dependent; optimized protocol; somaclonal variation; vaporphase
sterilization.
Abbreviations: 2,4-D; 2, 4-dichlorophenoxyacetic acid, BAP; 6-benzylaminopurine, MS; Murashige and
Skoog, NAA; α-naphthalene acetic acid, PGR; Plant growth regulator, SEM; Shoot elongation medium,
SIM; Shoot induction medium, RIM; Root induction medium.
