'水ナス'の加温栽培における最低気温が収量および果実品質に及ぼす影響(栽培管理・作型)  [in Japanese] Effect of Minimal Air Temperature on Yield and Fruit Quality of 'Mizunasu' Eggplant Grown in Heated Plastic House(Crop Production & Cropping Type)  [in Japanese]

近年普及し始めた'水ナス'加温栽培における温度管理技術を確立するため, 最低気温が, 加温栽培'水ナス'の収量および果実品質に及ぼす影響について検討した.最低気温14℃では, 葉に低温障害が現れるとともに, 総収量および可販果収量が16℃および18℃と比較して著しく少なかった.最低気温16℃と18℃との間に収量差は認められなかった.最低気温16℃および18℃で栽培された'水ナス'の果実品質を比較したところ, 果色には差がなく, 16℃で果形が細長くなった.しかし, その差はわずかであり, 外観上の品質には差が認められなかった.18℃では16℃よりも, 中果皮が有意に柔らかくなるとともに, 漬物加工時のNaClの浸透性が向上した.しかし, 現在'水ナス'の価格は外観上の品質によって決定されているため, 16℃と18℃との間には果実の価格差がなく, 現状では'水ナス'加温栽培の最低気温は暖房コストの安い16℃が適すると考えられる.

'Mizunasu' eggplants were grown in heated plastic houses kept at the minimum air temperature of 14℃, 16℃ and 18℃. At 14℃, low temperature injuries were observed and marketable yield was remarkably lower than that at 16℃ or 18℃. The yield and fruit color at 16℃ were similar to those at 18℃. The fruit shape at 16℃ was slightly more slender than that at 18℃. At 16℃, the mesocarp of the fruit was firm and the NaCl permeability into the fruit was decreased compared to that at 18℃. However, the 'Mizunasu' eggplant fruit is valued mainly by the appearance (fruit color and shape) in the present markets, so the market value of fruit cultivated at 16℃ was similar to that at 18℃. On estimation by yield, the appearance of fruits and the heating cost, the minimum air temperature of 16℃ was suitable for 'Mizunasu' eggplant production in heated plastic houses.