INFLUENCE OF PHOTOPERIOD AND MEDIUM FORMULATION ON PEANUT SOMATIC EMBRYOGENESIS

Somatic embryos were produced from peanut (Arachis hypogaea L.) immatu re zygotic cotyledons. Comparisons were made of the level of alpha-nap hthaleneacetic acid during induction, nitrogen formulation of the medi um, and photoperiod. Over 70% embryogenesis was obtained regardless of NAA level used. Percent embryogenesis and number of embryos were mark edly lower in explants induced on NAA compared to 2,4-D. Embryo produc tion was not greatly affected,by either the use of Murashige & Skoog v ersus Finer & Nagasawa salts or light versus dark culture conditions. However, embryo morphology was noticeably affected by photoperiod. Emb ryos produced under a 16 h photoperiod were tough, woody and difficult to separate for subsequent germination and conversion. Those produced under a 0-h photoperiod were succulent and pliable.