LOW-PUNGENT SWEET PEPPER SELECTED UNDER CONTINUOUS FLUORESCENT ILLUMINATION

Abstract

‘Shishito’ (Capsicum annuum L.) is a group of sweet pepper cultivars. Fruits are small, green and non-pungent, but pungent fruits sometimes occur. In our previous study, plants of ‘Shishito’ grew well and bore abundant fruits under continuous fluorescent illumination, however, pungent fruit strongly increased. In this study, mutation was induced and screening for low-pungent variants in M2-M3 was conducted under continuous fluorescent illumination. Seeds of ‘Shishi-Homare’ were treated with a 30 Gy 220 MeV 12C5+ beam. Self-fertilized M2 seeds were harvested from M1 plants individually. First screening was conducted in the field and 126 plants were selected from 762 plants. Second screening was conducted in a growth chamber under continuous fluorescent illumination, in which the concentration of the pungent compound capsaicin in the fruit placenta was determined with HPLC. One plant with the lowest capsaicin concentration was selected and self-pollinated. M3 plants were grown under continuous fluorescent illumination. The capsaicin concentration of M3 plants under continuous fluorescent illumination was lower than that of M2 plants however, plants with high capsaicin level still existed. One plant with the lowest capsaicin concentration was selected and self-pollinated. The capsaicin concentration of M4 plants under continuous fluorescent illumination was much lower than that of wild type ‘Shishi-Homare’; the average concentration of M4 plants was about one sixth of that of the wild type.