The yield of 'Daikichi', eddo cultivar (Colocasia esculenta Schott (L). var. antiquorum Hubbard & Rehder) cultivar generally grown in upland fields is increased by pot culture under flooded conditions. Here, we studied the effect of flooding on the photosynthesis in eddo under upland field conditions and flooded conditions in which flooding treatment started when two to three leaves emerged. In comparison with upland field conditions, stomatal conductance, transpiration rate, amount of chlorophyll and photosynthetic rate were increased with the plant growth under flooded conditions. The increase in transpiration under flooded conditions prevented the rise of daytime leaf temperature thus preventing the decrease in photosynthetic rate that occurs under high temperature conditions.

BACKGROUND: Taro (Colocasia esculenta cv. Daikichi) is believed to be one of the earliest cultivated tuber crops and it is a staple food in many parts of the world. The mother corm and side cormels (daughter and granddaughter tubers) form the major consumed parts; however, the former is rarely preferred. Taro is mainly cultivated using either unflooded or flooding cultivation, under dryland-rainfed and wetland-irrigated conditions, respectively. Although flooding cultivation has several advantages, such as lower risk of diseases, weeds, and insect pests, contributing to increased tuber yield, its effects on the quality characteristics of the tubers are largely unknown. In this study, the effects of controlled flooding cultivation on the quality of mother corm and side cormels were investigated. Their taste, color, physical properties, antioxidant activity, and starch, oxalic acid, nitrate ion, arabinogalactan (AG)/AG protein (AGP), γ-aminobutyric acid (GABA), and total polyphenol content was compared with those under unflooded cultivation. RESULTS: Flooding cultivation increased polyphenol levels and antioxidant activity and decreased oxalate, nitrate ion, GABA, and AG/AGP levels. Flooding cultivation also reduced the harshness and increased the hardness and stickiness of steamed mother corm paste, generally discarded under unflooded cultivation, thus rendering it suitable for consumption. CONCLUSION: Controlled flooding cultivation has economic advantages and the potential to improve the quality of cultivated taro.

No abstract