福岡県農業総合試験場研究報告22(2003) pp 37 - 37
近年の高温化に対応した水稲‘夢つくし’の品質向上のための最適移植時期
岩渕哲也・田中浩平・尾形武文・濱地勇次
（豊前分場）
近年の高温化に対応した水稲‘夢つくし’の品質向上のための最適移植時期を明らかにした。
１．移植時期が5月中・下旬〜6月中旬の範囲では，収量は6月中旬移植ではm2当たり籾数の減少により劣った。外観品質は5月中・下旬移植の早植で劣る年次がみられた。 一方，食味やタンパク質含有率は移植時期の早晩の違いによる差は認められなかった。
２．検査等級は出穂後20日間の平均気温が28℃を超えると乳白米比率と背白米比率の著しい増加のため顕著に劣った。したがって，登熟温度と外観品質，収量性および食味からみて豊前地域における‘夢つくし’の最適移植時期は6月2半旬であると考えられた。
[キ−ワ−ド：移植時期，外観品質，高温，水稲，背白米，乳白米，‘夢つくし’]
Optimum Transplanting Time for Improved Quality of appearance of the Rice Cultivar‘Yumetsukushi' under the Recent High Air Temperature Conditions.
IWABUCHI Tetsuya, Kohei TANAKA, Takefumi OGATA and Yuji HAMACHI(Fukuoka Agricultural Research Center, Chikushino, Fukuoka 818-8549, Japan) Bull. Fukuoka Agric. Res. Cent., 22: 34 - 37 (2003)
We suggested an optimum transplanting time for improved quality of appearance of the rice cultivar ‘Yumetsukushi' under the recent high air temperature conditions.
(1)When transplanted in the last ten days of May until he middle ten days of June, the number of spikelets per square meter decreased and the yield was inferior to when transplanted in the middle ten days of June. The quality of appearance of rice kernels was damaged in years when transplanting time was early as in the last ten days of May, however, the effects of transplanting time on protein content of milled rice and eating quality weren't significant.
(2)The inspection grade was significantly inferior when mean air temperature was higher than 28 ℃ in twenty days after heading because the rate of milky-white and white-back kernels was increased. Therefore, we suggest that in Buzen district, the ideal transplanting time for‘Yumetsukushi' based on air temperature conditions during the period of ripening is from June 6 to 10, in order to maximize it's quality of appearance, yield and eating quality.
[Key words: high air temperature, milky-white kernel, paddy rice, quality of appearance, transplanting time, white -back kernel, 'Yumetsukushi']