Effects of Plant Growth Retardants on the Growth and Characters Related with Lodging in Rice

생장조정제(生長調整劑) 처리(處理)가 수도생육(水稻生育) 및 도복관련(倒伏關聯) 형질(形質)에 미치는 효과(效果)

This study was conducted to investigate the effect of plant growth retardants on the growth and characters related with lodging in rice. The results are summarized as follows. Plant height which is closely related to lodging was significantly inhibited by the application of inabenfide, paclobutrazol, and uniconazole. Among the tested application times, inabenfide, paclobutrazol, and uniconazole were the most effective in inhibiting plant height at 30, 20, 20 days before heading respectively. Inabenfide was markedly effective in reducing the lower (4th) internode length, whereas paclobutrazol and uniconazole were more effective in reducing the upper (3rd and 2nd) internode length. Internode wall of rice plant treated with chemicals was tended to be thickened as compared with control. Heading date was not influenced by inabenfide, but paclobutrazol and uniconazole were inhibited 1 or 2 days in heading date as compared with control. Lodging index was the most reduced when inabenfide was applied 30 days before heading with 160g ai whereas paclobutrazol and uniconazole were applied 15 days before heading with 12, 1.2g ai per 10a, respectively. All the treatments inhibited the lodging of rice but control was completely lodged. Yield treated with these chemicals was prevented by 10-12% of yield decrease occurred by lodging. As a conclusion, inabenfide with 120 or 160g ai at 40 or 30 days before heading, paclobutrazol with 12g ai at 15 days before heading, arid uniconazole with 1.2g ai at 15 days before heading appear to be the most practical application time and rate for preventing lodging in paddy rice.

생장조정제(生長調整劑) 처리(處理)가 수도(水稻)의 생육(生育) 및 도복관련형질(倒伏關聯形質)에 미치는 효과(效果)를 시험(試險)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. Inabenfide, paclobutrazol, uniconazole 세 약제(藥劑) 모두 초장(草長) 억제효과(抑制效果)가 있었으며 약량(藥量)이 많을수록 억제효과(抑制效果)가 컸고, inabenfide는 출수전(出穗前) 30 일(日), paclobutrazol과 uniconazole은 출수전(出穗前) 20일(日) 처리(處理)에서 가장 억제(抑制)되었다. 2. Inabenfide는 하위절간(下位絶間)인 제(第) 4절간(絶間)은 억제(抑制)시킨데 비(比)하여 paclobutrazol과 uniconazole은 상위절간(上位絶間)인 제(第)3, 2 절간(絶間)을 각각(各各) 크게 억제(抑制)시켰다. 3. 약제처리(藥劑處理)에 의(依)한 간벽(稈壁)두께는 무처리(無處理)보다 전반적(全般的)으로 두꺼워지는 경향(傾向)이었으나 처리시기별(處理時期別) 약량별(藥量別) 일정(藥量別)한 차이(差異)는 보이지 않았다. 4. 출수기(出穗期)는 inabenfide 처리시(處理時) 무처리(無處理)와 동일(同一)하였으나 paclobutrazol과 uniconazol 처리시(處理時) 1~2일(日) 정도(程度) 지연(遲延)되었다. 5. 도복지수(倒伏指數)는 inabenfide의 경우(境遇) 출수전(出穗前) 30 일(日), 10a당(當) 성분량(成分量)으로 160g 처리시(處理時) 가장 낮은 지수(指數)를 보였으며 paclobutrazol과 uniconazale은 출수전(出穗前) 15일(日)에 10a당各(當) 각(各)12g, 1.2g 처리시(處理時) 가장 낮은 지수(指數)를 보였다. 6. 전약제(全藥劑) 처리구(處理區)에서 도복(倒伏)이 되지 않았던 반면(反面) 무처리구(無處理區)에서는 완전(完全)히 도복(倒伏)되었다. 7. 수량(收量)은 도복(倒伏)이 경감(輕減)되므로서 10~12%의 감수(減收)가 억제(抑制)되었다. 8. 결론적(結論的)으로 inabenfide는 출수전(出穗前) 40~30일(日)에 10a당(當) 성분량(成分量)으로 120~160g, paclobutrazol과 uniconazole은 출수전(出穗前) 15일(日)에 각각(各各) 12g, 1.2g을 처리(處理)하는 것이 가장 적당(適當)할 것으로 생각된다.