Biotypes, GR50, Herbicide resistance, Phalaris minor, Sulfosulfuron, Sulfosulfuron + metsulfuron

Two separate field experiments were conducted at the experimental farm of the Department of Agronomy, Lovely Professional University Phagwara, Punjab, during 2022-2023 and 2023-2024 to estimate the GR50 values of prominent herbicides, viz. sulfosulfuron + metsulfuron 30 g/ha and sulfosulfuron 25 g/ha against herbicide resistant populations of Phalaris minor collected from different districts of Punjab. Split Plot Design (SPD) was used with three replications. The sulfosulfuron + metsulfuron 30 g/ha, at recommended level caused significantly less mortality percentage resulting in significantly greater biomass of P. minor during both years as compared to its 2X dose. Among biotypes significantly less mortality was observed with Ropar biotype and significantly less biomass with Fazilka biotype as compared to Ferozepur and Ludhiana biotypes. The biomass of P. minor was also significantly higher with sulfosulfuron X level than 2X level of sulfosulfuron. Among all the biotypes significantly higher mortality and significantly less biomass was observed with Fazilka biotype as compared to other biotypes during both the years.