Fruit Set and Its Development of Pepper as Affected by Carbon Dioxide Enriched Atmospheres under Continuous Fluorescent Illumination

Abstract

The objective of this study was to investigate the effect CO₂ enrichment under continuous illumination on the fruiting ability of pepper cv. Kyo-midori grown in rockwool and the fruit quality was compared to that grown under natural light in a greenhouse. Controlled environmental conditions were ; light intensity 150μmol·m^-2 sec^-1 with fluorescent lamps, temperature 27±2°C, humidity 70±5% and CO₂ concentration was variable. Fruit was harvested when it was 2025g (ca. 18 days after anthesis). For plants grown under ambient CO₂ (340ppm), the cumulative number of fruits harvested during the 10 week period after first flowering was mean 57 per plant, and 8090 under elevated CO₂ (8001600ppm).
No difference was noted in dry matter partitioning, in which fruits constituted > 40% of the total plant dry matter. Leaf yellowing was observed 8 weeks after treatments of 1200 and 1600 ppm CO₂; thus 800 ppm may be the optimal level for long term fruit production under continuous illumination.
When compared to greenhouse peppers harvested in late June, those under continuous illumination had a lower starch content and similar sugar content, with a harder, greenish and glossy fruit skin.