Imazethapyr-Resistant Jungle Rice ( Echinochloa colona ) in Soybean Growing Belt of Central India: A Case Study

The Jungle rice [ Echinochloa colona (L.)Link] is one of the major weed of soybean, which causes significant yield loss. Poor efficacy of imazethapyr for controlling E. colona weed in soybean was reported by farmers. Therefore, a survey was conducted in 21 soybean growing districts of Central India and 94 E. colona biotypes were collected. Net house experiments were conducted in 2017 and 2018 to evaluate resistance of E. colona biotypes against imazethapyr. Imazethapyr was applied at dose of 100, 200 and 400 g ha −1 at 4–5 leaf stage of E. colona . During initial screening E. colona biotypes from 15 districts were found with variable level of resistance. During second generation of screening, highly resistant biotypes from Ashoknagar (APS), Indore (IAS and IFS), Dhar (DBS), Sagar (SaSS1 and SaDS), Hosangabad (HoRS1and HoRS2) was identified with LD 50 > 1000 g ha −1 . The resistance index indicated that resistant biotypes were 18–11,650 fold more resistant than the susceptible ones. Thus, this is the first report of imazethapyr-resistant jungle rice in soybean from India.