Varietal Differences and Diallel Analysis of Pre-germination Flooding Tolerance in Soybean Seed

Seven hundred and thirty varieties of soybean from different sources were evaluated for seed flooding tolerance by the seed germination test after a 4-day soaking at 25℃. The inheritance of seed flooding tolerance was also analyzed with a 6 x diallel cross. A large variation in seed flooding tolerance existed in the soybean germplasm as reflected in the germination rate which ranged from 0 to 100%. Most of the varieties tested were sensitive to seed flooding, and only 4% of the tested varieties showed a high tolerance (germination rate >90%). Seed flooding tolerance was controlled by both additive and dominance genes and a small number of effective factors and high narrow sense heritability in diallel analysis indicate that the selection for tolerance can effectively be done in early generations.

起源の異なる730品種の大豆種子を25℃、4日間浸漬処理し、その後の発芽率で種子の冠水抵抗性を評価した。また、種子の冠水抵抗性の遺伝様式6×6のダイアレル分析で調査した。供試した品種の冠水処理後の発芽率は0～100％まで分布し、種子の冠水抵抗性には大きな変異が認められた。大部分の品種は冠水条件に感受性であり、供試品種の4％のみが高度の抵抗性（発芽率90％以上）を示した。ダイアレル分析の結果、種子の冠水抵抗性は、相加的効果と優性効果が有意であり、優性効果の方が相加的効果よりも重要であった。種子の冠水抵抗性を支配する遺伝子は2対、狭義の遺伝率は0.47と推定され、抵抗性の強い方が劣性なので、初期世代における選抜効果が期待できる。