Optimal Transplanting Time for 'Saemimyeon' Production in Youngnam Province

'Saemimyeon,' a Tongil-type rice variety (Indica x Japonica), containing high amylose content, is suitable for rice noodle production. Currently, the major parts of the rice processing industry that include products such as rice flour and noodles are expected to partially replace the wheat flour market. The volume of the rice noodle market is growing and can contribute to the rice surplus problems and farmer's income. This study was carried out to promote productivity of 'Saemimyeon' by finding the most suitable transplanting times in Youngnam Province. The transplanting times were May $10^{th}$, May $17^{th}$, May $24^{th}$, May $31^{th}$, June $7^{th}$, and June $14^{th}$ and the planting distance was $30{\times}12cm$. The field experiment was conducted in the Miryang region (southern plain region of Korea) from 2015 to 2017. Our results suggested that the optimum transplanting dates were from May $17^{th}$ to May $31^{th}$, which resulted in an average yield of 750 kg/10 a. The average grain filling rate before May $31^{th}$ was more than 83% and it declined to 75% after June $7^{th}$. The average temperature range from heading to harvesting time was $21{\sim}25^{\circ}C$ and the estimated optimal temperature was $24^{\circ}C$, which is similar to that of May $24^{th}$ by regression equation. It is suggested that low temperature at seed maturation time caused the lower grain filling rate, and therefore 'Saemimyeon' needed to be transplanted before May $31^{th}$ for higher productivity. Estimated optimal transplanting time based on temperature was 1 ~ 2 weeks earlier than the optimum transplanting time for common japonica rice cultivars in Youngnam Province.

영남지방에서 쌀면용 새미면 최대생산을 위한 이앙적기 설정

본 실험은 새미면의 영남지역 지역별 최대 수량 생산을 위한 최적 이앙기를 설정하기 위해 2015~2017년 까지 3년간 밀양에서 실시하였다. 1. 밀양지역에서 최대수량 생산을 위한 새미면의 최적 이앙기는 5월 17일~31일로 이때 쌀수량은 750 kg/10a정도였다. 2. 새미면의 최적 등숙기 평균기온은 출수 후 40일 평균기온을 기준으로 $24^{\circ}C$ 내외였다. 3. 밀양에서 등숙기 평균기온이 $24^{\circ}C$ 내외인 이앙기는 5월 17일~24일로 등숙기 평균기온은 $23.8{\sim}24.5^{\circ}C$였다. 4. 등숙기 평균기온 $23.8{\sim}24.5^{\circ}C$를 기준으로 추정한 지역별 최적 이앙시기는 대구 5월 24일~31일, 구미 5월 11일~21일, 밀양 5월 21일~28일, 진주 5월 14일~22일 등 이었다. 5. 새미면은 일반적으로 알려진 통일형벼의 최적 등숙기온 $25^{\circ}C$ 보다 $1^{\circ}C$ 낮은 $24^{\circ}C$ 정도가 최적 등숙기온으로 통일형벼 중에서 비교적 낮은 온도에도 안전하게 재배할 수 있는 품종이었다. 또한 수량성이 다른 통일형벼에 비해 높아 통일형벼의 재배한계 지역을 더 넓힐 수 있는 품종으로 사료된다.