Regeneration of pepper (Capsicum annuum L. and evaluation of antioxidant compounds at various ripening stages
A laboratory study was conducted to develop a broadly applicable in vitro regeneration method for pepper. Therefore, ten different pepper genotypes were analyzed with regard to their efficiency for regeneration in vitro Cotyledons were used in vitro from young seedlings as target tissue for regeneration of pepper. Multiple shoot was induced by culturing cotyledons explants in MS medium supplemented with 0.28 uM IAA and 13.86 uM Zeatin. Results strongly showed that there were significant differences between pepper genotypes. Generally the highest values of all regeneration parameters were obtained from genotypes Balady, Ciliegia piccante and Yellow California wonder. Genotype Hot Horn had the lowest regeneration parameters while other genotypes were moderate response. The rooted shoots were transferred to the greenhouse and showed a normal development to mature plants. Changes in antioxidant constituents (ascorbic acid, phenolics, and carotenoids) were monitored during three maturity stages in 10 genotypes of pepper. In an attempt to explain the variations during maturity stages (green, intermediate and red/ yellow) the data was expressed on dry weight basis. Ascorbic acid content declined progressively with advancing maturity. Genotype Sigaretta di bergano had the maximum content (2999.0 mg/100 g dry weight) at the green stage. On dry weight basis, phenolic content declined in majority of the genotypes during maturity to red stage. This decline was significant in Ciliegia piccante, California wonder, Sigaretta di bergano and Balady. Genotype Balady and Yellow California wonder had the highest phenolic content of 833.0 mg/100 g and 723.0 mg/100 g, at their final red and yellow maturity stages, respectively. With maturation, total carotenoids and b carotene content increased significantly of most genotypes. Topepo rosso was a promising genotype in terms of both total carotenoids and b carotene content. The study proposes the nutritional significance of consuming peppers at the red maturity stage because of enhanced functional properties. Overall genotype Balady and Topepo rosso represent superior genotypes for both nutrition and germplasm improvement.