In vitro shoot-forming capacity of cotyledon explants in red pepper (Capsicum annuum L. cv. Yatsufusa).

Abstract

Some of the factors which influence the in vitro shoot-forming capacity of cotyledon explants of red pepper (Capsicum annuum L. cv. Yatsufusa) were studied. Benzyladenine (BA) was found to be more effective than kinetin (K) in inducing shoot formation in cotyledon explants cultured on MURASHIGE and SKOOG (MS) medium. Among the BA levels tested, BA at a concentration of 3 to 7 mg/l induced the largest number of shoots per explant. Auxin (indoleacetic acid and naphthaleneacetic acid) in combination with cytokinin (BA) inhibited shoot formation but promoted callus and root formation. Cotyledon explants excised from the 12-day-old seedlings gave the largest number of shoots per explant and the frequency of shoot formation was significantly decreased as the age of the seedlings increased. Intact cotyledon with petiole and trimmed cotyledon with petiole showed a significantly higher frequency of shoot formation than blade and petiole of cotyledon. Among four kinds of growing media on which seeds were sown and seedlings were grown, full-strength MS solution and half-strength MS solution were found to be more effective than tap water for the induction of shoot formation on cotyledon explants. The highest percentage of shoot-forming explants and the largest number of shoots per explant under the defined optimum conditions were different in each trial, ranging from 90 to 100 per cent and 8.6 to 11.9, respectively. Shoots were rooted when transferred to the same medium supplemented with indoleacetic acid or naphthaleneacetic acid at the concentration of 0.5 mg/l and complete plantlets could be regenerated within 7 weeks after the beginning of culture.