This study evaluates the effectiveness of in vitro regeneration of 4 genotypes of pepper (Capsicum spp.) that differ in origin and functional properties: California Wonder, (ATZ × Sono)F1, Jalapeno, and SF-9. The highest number of adventitious leaves was recorded in the decapitated seedlings exposed to continuous light. | Turkish Journal of Biology Research Article Turk J Biol (2015) 39: 60-68 © TÜBİTAK doi: In vitro plant regeneration of 4 Capsicum spp. genotypes using different explant types Marta ORLIŃSKA*, Pawel NOWACZYK Department of Genetics, Physiology, and Plant Biotechnology, University of Technology and Life Sciences in Bydgoszcz, Bydgoszcz, Poland Received: Accepted: Published Online: Printed: Abstract: This study evaluates the effectiveness of in vitro regeneration of 4 genotypes of pepper (Capsicum spp.) that differ in origin and functional properties: California Wonder, (ATZ × Sono)F1, Jalapeno, and SF-9. In order to investigate the effect of the initial explant type, photoperiod, and presence of mg L–1 of glycine in the medium, organogenesis was induced on the MS medium with g L–1 2-(N-morpholine) ethanesulfonic acid, mg L–1 AgNO3, mg L–1 indole-3-acetic acid (IAA), and mg L–1 6-benzyladenine. The effectiveness of organogenesis in the 3 genotypes representing C. annuum L. was similar and considerably lower for line SF9 derived from an interspecific hybrid (C. frutescens L. × C. annuum L.). The highest number of adventitious leaves was recorded in the decapitated seedlings exposed to continuous light. The lack of glycine in the medium favored direct organogenesis. A simultaneous formation of adventitious leaves with a stable number of chromosomes and mixoploid callus tissue was determined by flow cytometry. The successive stage of foliaged shoots and roots formation was most effective in the MS medium with mg L–1 IAA. The use of these optimal conditions resulted in developing 42%–56% of properly formed diploid plantlets, successfully acclimatized in 86%–97%. Key words: Elongation, flow cytometry, regeneration, pepper, organogenesis, rhizogenesis 1. Introduction Pepper (Capsicum spp.) fruits are one of the most important vegetables in .