HPPD 효소를 저해하여 카로티노이등 생합성을 억제하는 최근에 등록된 제초제 benzobicyclon 및 mesotrione+pretilachlor에 대한 통일형(장립종) 및 일반벼(단립종)간 약해 발생 차이 및 수량영향을 조사한 결과는 다음과 같다. 1. 제초제 MP 및 bezobicyclon에 대한 약해 반응은 벼 생태형에 따라 달랐는데 통일형 벼인 한아름벼, 한아름2호, 다산벼는 대부분 약해인 백화증상이 나타났으나 일반형인 주남조생, 일미벼, 주남벼는 약해증상을 거의 보이지 않았다. 제초제 별로는 MP가 benzobicyclon보다 초기에 약해발생이 심하였으나 후기에는 차이가 없었다. 통일형 벼는 제초제 처리 후 5일부터 백화증상을 보였고 10일에 약해증상이 뚜렷하였으며 처리 후 20일에는 약해증상이 처리 후 10일 보다 약해지는 경향이었다. 제초제 처리에 따른 카로티노이드 합성은 백화현상과 비슷하게 butachlor 대비 MP 처리가 benzobicyclon처리보다 초기에 더 억제가 되었으나 후기에는 차이가 없었다. 3. Benzobicyclon 및 MP 처리에 대한 약해로 통일형벼의 출수기가 butachlor 처리보다 3일가량 지연되었고, $m^2$당 수수가 11~50개가 적고 등숙비율이 0.9~7.5% 낮아져 쌀 수량은 benzobicyclon 처리가 7~10%, MP처리는 3~5% 감수하였다. 4. 하지만 일반형 품종은 benzobicyclon 및 MP를 처리해도 출수기, 벼 생육특성 및 쌀 수량은 butachlor처리와 차이가 없었다.
A field study was conducted at Miryang in 2011 to evaluate differential sensitivity of six rice cultivars, three Indica${ imes}$Japonica rice (long grain, cv. Hanareumbyeo, Hanareum2, Dasanbyeo) and three Japonica rice (short grain, Nampyung, Ilpumbyeo and Junamjosaeng) cultivars, to benzobicyclon, mesotrione+pretilachlor (MP) and butachlor (control) in transplanting rice and their treatment influences on rice yield. All Indica${ imes}$Japonica rice cultivars exhibited susceptible to both benzobicyclon and MP as reflected by higher visual injury and carotenoid biosynthesis inhibition when compared with Japonica rice cutlivars. The percentage of foliar chlorosis of Indica${ imes}$Japonica rice was only 0.9~4.7% for benzobicyclon at 13 days after treatment (DAT) and 30.3~64.4% for MP at 5DAT but it increased rapidly to 88.4~91.2% at 12~20DAT. However, most of the Japonica cultivars are tolerant to bezobicyclon and MP. There was no visible leaf chlorosis but carotenoid biosynthesis was slightly inhibited. Based on relative carotenoid content reduction of benzobicyclon and MP to butachlor, the Indica${ imes}$Japonica rice showed 4.6~15.6 fold higher compared with the Japonica rice. The heading date of the injured rice plant was delayed by 3 days and panicle number per square meter and ripened grain ratio were reduced as compared with the control treatment of butachlor. Rice yield of the Indica${ imes}$Japonica rice cultivars treated with benzobicyclon and MP was reduced by 7~10%, 3~5%. respectively. The result indicates that rice cultivars vary in tolerance to HPPD-Inhibiting herbicides and Indica${ imes}$Japonica rices were more susceptible than the Japonica rices to MP and benzobicyclon. Rice yield of the Indica${ imes}$Japonica rices was also significantly reduced by the those herbicide treatments.
