Thidiazuron-Induced Tissue Culture Regeneration from Quartered-Seed Explants of Arachis Paraguariensis

Arachis paraguariensis Chodat & Hassl. is a potential source of novel genes for the genetic improvement of cultivated peanut (Arachis hypogaea L.) because some of its accessions show high levels of resistance to early leaf spot caused by Cercospora arachidicola Hori. In this study, induction of high frequency shoot regeneration from quartered-seed explants was accomplished for six plant introductions of A. paraguariensis under continuous light on Murashige and Skoog (MS) medium containing 4.4 mg L-1 thidiazuron (TDZ) in combination with 2.2 mg L-1 6-gamma-gamma-(dimethylallylamino)-purine (2ip). Recovery of a moderately high number of plantlets per quarter seed cultured was also achieved on medium containing 4.4 mg L-1 thidiazuron in combination with 1.1 to 4.4 mg L-1 6-benzylaminopurine (BAP) with bud formation occurring as early as 1 wk after culture initiation. There were no differences in seed production or in early leaf spot incidence between plants of two genotypes of A. paraguariensis derived from seeds vs. in vitro tissue culture derived plants; however, cultivated peanut cv. Florunner had a higher incidence of early leaf spot.