抄録
北海道内全域で栽培されたダイズのイソフラボン含量を調査したところ,同一品種でも栽培地によって含量は変動し,登熟期間の平均気温(以下,登熟気温)との間に有意な負の相関が認められた.また,同一栽培地での明らかな品種間差も確認され,「ゆきぴりか」および「音更大袖」の含量が最も高かった.ゆきぴりかは,各適応地帯において標準品種(トヨコマチ)比1.3〜1.5倍の高含量を示す一方,栽培地間の変動係数は年次間変動を含めても標準品種より低かった.また,ゆきぴりかの高イソフラボンは,登熟後半におけるダイズイン類の蓄積が一般品種より顕著であることに起因しており,ダイズイン類のゲニスチン類に対する比率(D/DG率)も高まっていたが,品種間および交雑後代系統間にイソフラボン含量とD/DG率の有意な相関は認められず,これらは,独立した遺伝形質であると推察された.一方,D/DG率は同一品種でも栽培地によって変動し,イソフラボン含量と同様に登熟気温と有意な負の相関が見られたことから,イソフラボン蓄積を促進する条件は,D/DG率の決定にも何らかの影響を及ぼしていると考えられた.
The isoflavone content of soybeans cultivated in Hokkaido was investigated, in terms of varietal and local differences. There was a significant negative correlation between isoflavone content and temperature during the seed-filling period, in each cultivar cultivated in various experimental locations in Hokkaido. "Yukipirika" had the highest isoflavone content, followed by "Otofuke-Osode". "Yukipirika" had a 1.3-1.5-fold higher isoflavone content than the standard cultivar in any experimental location, and had lower coefficients of variation among locations and years. In "Yukipirika", the accumulation of daidzin (and its relatives) was especially high, and the ratio of daidzin to genistin (D/DG ratio) was high. However, the isoflavone content and D/DG ratio did not significantly vary with the cultivar and progeny. On the other hand, the D/DG ratio in the same cultivar cultivated in various locations negatively correlated with the temperature during their seed-filling period, suggesting that the conditions that accelerate the isoflavone accumulation would also affect the D/DG ratio.
