Dadarwal, R. SSushil Kumar2023-02-102023-02-102022-12https://krishikosh.egranth.ac.in/handle/1/5810193549Phalaris minor is the most problematic weed in wheat crops, especially in rice-wheat cropping systems. Haryana, an important grain-producing state, is seeing a significant decline in productivity and profitability as a result of P. minor infestation. After developing multiple herbicide resistance, the threat posed by P. minor has grown. Assessing and quantifying the degree of resistance in P. minor biotypes is essential for the logical recommendation and execution of management techniques. Therefore, pot and field study were performed under the investigation entitled, “Studies on multiple herbicide resistance in Phalaris minor and its management through pre and post emergence herbicides in wheat”. The pot experiment was performed at screen house and field study was conducted at Agronomy Farm, CCSHAU, Hisar (Haryana). The level of resistance in fourteen P. minor biotypes to different herbicides i.e. clodinafop, sulfosulfuron, mesosulfuron + iodosulfuron (Ready mix) and pinoxaden at various graded doses i.e. ½ X, X (recommended), 2 X and 4 X was evaluated and quantified in experiment I (pot study). In field experiment, the efficacy of pendimethalin 1500 g/ha, flumioxazin 125 g/ha, flumioxazin + pendimethalin (TM) 125 + 1500 g ha-1, pyroxasulfone + pendimethalin (TM) 127.5 + 1500 g ha-1, metribuzin 315 g ha-1, mesosulfuron + iodosulfuron (RM) 14.4 g ha-1, sulfosulfuron + metsulfuron (RM) 32 g ha-1, pinoxaden + metsulfuron (TM) 50 + 4 g ha-1 and clodinafop propargyl + metribuzin 174 g ha-1 applied as pre and post emergence in different combinations. In Experiment 1, most of the biotypes were found highly resistant to clodinafop. Rasidan (Jind) biotype was most resistant to clodinafop with visual control of only 15.5 % at 4X dose of clodinafop followed by Urlana Kalan (Panipat). Recommended dose of sulfosulfuron was not enough to fully control the P. minor biotypes. Rasidan (Jind), Teek (Kaithal) and Kanheri (Fathehabad) biotypes were highly resistant to sulfosulfuron. Beri (Jhajjar) and Nirjan (Jind) biotypes were completely controlled at recommended dose of mesosulfuron + iodosulfuron (RM). At recommended dose of pinoxaden Jammu (J & K), Aanta (Panipat), Kharian (Sirsa), Beri (Jhajjar), Ikkas (Jind), Kheri Raiwali (Kaithal), Balambha (Rohtak) and Nirjan (Jind) biotypes were found fully sensitive. All of the investigated biotypes showed resistance to ACCase inhibitors, with more biotypes exhibiting high clodinafop resistance than pinoxaden. However, ALS inhibitors were effective against the bulk of the biotypes. In field experiment, PRE application of flumioxazin + pendimethalin (TM) 125 + 1500 g/ha, pyraxosulfone + pendimethalin (TM) 127.5 + 1500 g/ha fb mesosulfuron + iodosulfuron (RM) 14.4 g/ha, sulfosulfuron + metsulfuron (RM) 32 g/ha or pinoxaden + metsulfuron (TM) 50 + 4 g/ha as POE found more effective in reducing weed density and dry weight of P. minor and broadleaved weeds as compared to PRE pendimethalin alone fb application of post emergence herbicides. Application of flumioxazin 125 g/ha alone or in tank mix with pendimethalin 1500 g/ha (PRE) resulted in severe phytotoxicity (yellowing of leaves and stem) to wheat after 2-3 days of 1st irrigation (25-27 DAT). Higher grain yield (5847-5369 kg/ha) of wheat was reported with pyroxasulfone + pendimethalin (TM) 127.5 + 1500 g/ha (PRE) fb POE mesosulfuron + iodosulfuron (RM) 14.4 g/ha (60-69.5 % higher than weedy check) and it was statistically at par with pyroxasulfone + pendimethalin (TM) 127.5 + 1500 g/ha was used as PRE fb POE pinoxaden + metsulfuron (TM) 50 + 4 g/ha (59.1-68.6 % higher than weedy check) and pyroxasulfone + pendimethalin (TM) 127.5 + 1500 g/ha (PRE) clodinafop propargyl + metribuzin (RM) 174 g/ha (54.1-64.7 % higher over weedy check) during both the years of study.EnglishThesis