식물생장 조절제 Uniconazole-P의 처리가 초지조건에서 목초의 생육억제와 종자생산에 미치는 영향을 검토하였다. 초종은 화본과 목초 2초종(orchardgrass와 timothy)과 두과목초 2초종(red clover와 alfalfa)을 공시하였고, Uniconazole-P의 처리농도는 대조구, 20ppm구, 40ppm구의 3처리로 하여, 화본과 목초는 유수분화기에, 두과목초는 개화시기(開花始期)에서 엽면산포하였다. 본 실험에서 얻어진 결과를 요약하면 다음과 같다. 1. Uniconazole-P의 처리효과는 처리농도, 초종 및 생육단계에 따라서 차이가 인정되었다. 2. Uniconazole-P의 처리는 출수초기의 화본과 목초에서 초장과 간장이 단축되었고, 수중과 엽록소 함량을 증가시켰다. 3. Uniconazole-P의 처리는 종자 결실기의 orchardgrass에서 수수, 1경중, 수중, 1수중 및 종자중을 증가시켰고, timothy에서는 초장의 단축과 수수, 1수중, 수중, 종자중 및 수확지수를 증가시켰다. 4. Uniconazole-P의 처리는 개화초기의 red clover와 alfalfa 2초종 모두 초장과 총절간장을 단축시켰지만, 총분지장과 엽록소 함량을 증가시켰다. 특히 red clover에서는 화수와 화중의 증가가 현저하였다. 5. Uniconazole-P의 처리는 종자 결실기의 red clover에서 초장을 단축시켰고, 화중과 종자중을 증가시켰으며, alfalfa에서는 초장을 단축시키고 화중, 종자중 및 수확지수를 증가시켰다. 6. Uniconazole-P의 처리에 의한 화본과 목초의 종자 생산과정은 1) 출수초기에서 초장과 간장의 단축, 2) 출수초기와 종자 결실기에서 수수와 l수중의 증가, 3) 종자 결실기에서 단위면적당 수중과 종자중의 증가 및 수확지수의 증가로 설명할 수 있다. 7. Uniconazole-P의 처리에 의한 두과목초의 종자 생산과정은 1) 개화초기에서 초장과 총절간장의 단축과 분지수와 총분지장의 증가, 2) 개화초기와 종자 결실기에서 화수와 화중의 증가, 3) 종자 결실 기에서 종자중과 수확지수의 증가로 설명할 수 있다.

The purpose of this study is to clarify the effect of plant growth regulator "Uniconazole-P" on the control of growth and seed producrtion of pasture plants under grown in sward conditions. Four species examined were orchard grass, timothy, red clover and alfalfa. Uniconazole-P concentrations were control(0), 20ppm and 40ppm, and foliar sprayed on canopy structures at the floral differentiation stages of grasses and at the begining of flowering stages of legumes, respectively. 1. Yield components and seed yield components of grasses and legumes were responded differently between Uniconazole-P concentrations, species and the stages of growth. 2. At early heading stages, the plant length and culm length of grasses were reduced by Uniconazole-P treatments. On the contrary, the dry weight of ears per area and chlorophyll concentrations were increased by Uniconazole-P treatments. 3. At seed ripening stages, the number of ears, dry weight of a tiller, dry weight of a ear, dry weight of ears per area and dry weight of seeds in orchardgrass, and the number of ears, dry weight of a ear, dry weight of ears per area, dry weight of seeds and harvest index in timothy were increased by Uniconazole-P treatments. 4. At early flowering stages, the plant length and total length of internodes were reduced by Uniconazole-P treatments. On the contrary, total length of branches and chlorophyll concentrations of red clover and alfalfa were increased by Uniconazole-P treatments. Particularly, the number of inflorescences and dry weight of inflorescences of red clover was increased greatly by Uniconazole-P treatments. 5. At seed ripening stages, the plant length of both of legumes were reduced by Uniconazole-P treatments. On the contrary, the dry weight of a inflorescence, dry weight of inflorescences per area, dry weight of seeds and harvest index of alfalfa was increased by Uniconazole-P treatments. 6. Seed production of grasses by Uniconazole-P treatments can be explained as following processes at each stage of growth. 1) reduced in plant length and culm lengths at early heading stages, 2) increased in number of ears and dry weight of a ear at both of stages, and 3) increased in dry weight of ears per area, dry weight of seeds and harvest index at seed ripening stages. 7. Seed production of legumes by Uniconazole-P treatments can be explained as following processes at each stage of growth. 1) reduced in plant length and total length of internodes and increased in number of branches and total length of branches at early flowering stages, 2) increased in number of inflorescences and dry weight of inflorescences at both of stages, and 3) increased in dry weight of seeds and harvest index at seed ripening stages.

• 이주삼(연세대학교 생물자원공학과) | Ju Sam Lee