杂交稻制种田九二○用量与种子中GA_3含量及F_1代产生徒长苗的关系

在杂交稻制种时，为了调节不育系的生长，促进异交结实，提高制种产量，喷施九二①是一项重要措施。近年来，九二①的单位面积施用量有逐年增大的趋势。由此引发出一个颇有争议的问题，即大剂量（明显超过每667m’8～12g的正常用量）的施用九二①会不会引起F；代幼苗产生类似恶菌病的徒长苗？因为近些年来，有些地方的杂交稻中恶苗病徒长苗明显增多，甚至造成严重损失。然而对其产生的原因看法却不一致，一种观点认为”－”，这与杂交稻制种时过量使用九二0有关；另一种观点则认为’‘’，制种田使用九IO后，种子中有赤霉素残留，但不会引…

Relation between the Dosage of Gibberellin in Hybrid Rice Production and the Content of GA_3 in Hybrid Rice Seed,the Elongation of the F_1 Seedling

The tested results indicated that the elongating seedling was induced when the content of GA3 in rice seed per gram was equal to or more than 94. 6 ng. The content of GA3 in F1 seed per gram was 23. 8, 49. 5, 53. 5 and 63. 5 ng respectively when the dosage of gibberellin was 0, 8, 13 and 18 g per 667 m2 in the hybrid rice seed production. These contents in the hybrid rice seed were much less than 94. 6 ng which could induce the rice seed to grow up elongating seedling. However, significant correlation existed between the content of GA3 in F1 seed and dosage of gibberellin in hybrid rice seed production. The further experiments proved that all of the aforementioned dosage of gibberellin could not induce the elongating seedling in F1 and that the elongating seedling in hybrid rice was caused by Gibberella fuiikuroi which infected the seed during blooming stage.