Peanut (Arachis hypogaea L.) plants (cvs Florunner and Pronto) were inoculated at the two‐leaf stage with peanut mottle virus (PMV) to obtain PMV‐infected plants. Shoot‐tips from plants grown in the glasshouse (27°C) or from plants maintained at 35°C were used for tip culture. In some experiments ribavirin was added to the culture medium at 5 mg/1, 10 mg/1, 15 mg/1 or 20 mg/1. Plants regenerated from meristems or shoot‐tips taken from virus‐infected plants were not virus‐free. After 45 days at 35°C, foliar tissue of 93 % of Florunner and 95 % of Pronto plants tested negative for PMV by enzyme‐linked immunosorbent assay (ELISA). When shoot‐tips from the plant that tested negative by ELISA were used for tip culture, no virus‐free plants were obtained. No virus‐free plants were obtained from tips cultured on medium supplemnted with ribavirin. However, when tip culture, thermotherapy and chemotherapy were combined; 80 % of Florunner and 100 % of Pronto plants were found negative for PMV.

Shoot-tips of peanut (Arachis hypogaea L.) cultivars Florunner and Pronto grown in the greenhouse, and the tips of A. villosulicarpa Hoehne from in vitro cultured plants were used for in vitro regeneration of peanut. The terminal and lateral buds excised from greenhouse grown plants were surface sterilized with 70% ethanol for 3 min followed by 0.525% sodium hypochlorite for 5 min. Shoot-tips (0.5–3 mm long) were isolated from the buds, transferred to a modified Murashige Skoog (MS) agar medium, and maintained at 26 C with a 16-h photoperiod. The modified MS medium contained MS mineral salts, B5 vitamins, and the hormones 1-naphthaleneacetic acid (NAA) and 6-benzyladenine (BA). The best growth of meristems (0.5–1 mm) was induced with 5.0 μM NAA and 5.0 μM BA. Rooting was induced with 5.0 μM NAA. Both shoot growth and rooting occurred on medium that contained 5.0 μM NAA when large tips (1–3 mm) were cultured. Plantlets regenerated from the tips were successfully transferred to pots and grown to maturity.