Su Hyuk Park

A Survey of Weeds Occurrence on Paddy Fields in Chungnam Province in Korea

우리나라 농경지에 발생하는 잡초는 1972년 한국산잡초 목록(국립농업자재연구소)이 발간됨으로써 453종이 처음 으로 알려졌다(Lee et al., 2012). ‘논잡초 발생 양상에 관 한 연구’는 1971년에 처음으로 농촌진흥청 작물시험장 주 관으로 실시되었으며, 그 후 10년 주기로 현재까지 총 네 번의 조사가 이루어졌다(Kim, 1983; Park et al., 1995; Park et al., 2001; Park et al., 2002). 네 번에 걸친 논 잡초 발 생조사에서 우점 잡초의 순위에 많은 변화가 있었고, 경 지 이용형태의 변화, 토지 기반정비에 의한 입지조건의 변 화, 경종법, 재배관리, 특히 경운정지나 잡초 방제법의 변 화 등이 농경지에서 발생하는 잡초군락 천이의 주요 요인 으로 작용한 것으로 나타났다(Kim et al., 2012). 손제초에 의존하던 1970년대의 발생잡초의 비율을 보면 화본과 12%, 광엽잡초 50%, 방동사니과 19%, 기타 19% 등으로 나타났으며, 일년생과 다년생 잡초의 분포 비율이 7:3으로 일년생 잡초의 분포 비율이 높았고, 마디꽃, 쇠털 골, 물달개비, 알방동사니, 피, 밭뚝외풀, 가래, 사마귀풀, 올방개 순으로 우점하는 것으로 조사되었다. 뷰타클로르 입제와 같은 일년생 잡초 방제용 제초제의 사용이 증가된 1981년에는 화본과 7.4%, 광엽잡초 66.7%, 방동사니과 ABSTRACT. The survey of weed occurrence was conducted to identify problem weed species in the paddy field. The 320 sites of the 13 regions in Gyeongbuk Province were investigated from June to July, 2013. In the whole region, 51 weed species were identified including 34 annuals and 17 perennials. The highest importance value of annual weed and perennial was dominant 88.4 and 48.7%, in Gumi region, respectively. The most dominant weed species in paddy fields of Gyeongbuk Province were Monochoria vaginalis var. plantaginea (10.80%), followed by Lemna paucicostata (10.74%), Bidens tripartite (8.77%), Echinochloa oryzoides (7.17%), and Scirpus juncoides (6.20%). The similarity of paddy weeds in 13 regions observed through TWINSPAN analysis was distinguished by Ludwigia prostrata, Scirpus juncoides, Lindernia dubia, Polygonum aviculare, and Alopecurus aequalis var. amurensis. The weed species, Ludwigia prostrata, was divided into the four regions, Gyeongju, Gumi(direct seeding cultivation), Youngcheon and Euiseong and ten regions, Gumi, Bonghwa, Sanju, Goryung, Youngdeog, Pohang, Sanju, Andong, Yecheon, and Cheongdo.

Identification of Herbicide-Resistant Barnyardgrass (Echinochloa crus-galli var. crus-galli) Biotypes in Korea

The continuous use of acetolactate synthase (ALS) and acetyl-CoA carboxylase (ACCase) inhibitors has led to the selection of herbicide resistant barnyardgrass populations in direct-seeded rice fields of Korea. This study was conducted to identify herbicide resistant barnyardgrass biotypes and to determine the cross- and multiple-resistance of them. 25% of the population collected from Taeahn was partially resistant to ACCase inhibitors and 22% collected from Kimjae were partially resistant to ALS inhibitors. However, 8.2% of the population from both sites was resistant to ALS and ACCase inhibitors. Resistance to sulfonylurea herbicide, flazasulfuron was identified from two barnyardgrass accessions collected from both Taeahn and Kimjae. One barnyardgrass accession from both sites was resistant to ACCase inhibitor, sethoxydim. The cross-resistance to ALS inhibitors was identified at one barnyardgrass accession from Taeahn and at two accessions from Kimjae. Further, crossresistance to ACCase inhibitors was also identified at barnyardgrass accessions from Taeahn and Kimjae. Multiple-resistance to flazasulfuron and sethoxydim was determined at four barnyardgrass accessions from Taeahn and at six accessions from Kimjae. Therefore, the herbicide mixture and sequences within a growing season or the herbicide rotation with different modes of actions across growing seasons are recommended to control herbicide-resistant barnyardgrass in infested fields.