RESPONSE OF SESAME ( SESAMUM INDICUM L.), ASSOCIATED WEEDS AND SUBSEQUENT CROPS TO PRE- AND POSTEMERGENCE HERBICIDES

Sesame (Sesamum indicum L.) is employed in many countries in the food, pharmaceutical, and other industries due to its high oil, antioxidant, and protein content for human consumption and cattle feed, as well as straw fodder. The current study aimed to investigate the herbicidal effects of preemergence and post-emergence herbicides on the morphological and physiological traits of sesame and associated weeds under field conditions. The current study employed two commercial pre-emergence herbicides pendimethalin (Fist super 45.5% CS) and metribuzin (Marine El-Nasr 70% WG), and three post-emergence herbicides namely haloxyfop-methyl (Galint super 10.8% EC), clethodim (Secrit 12% EC) and mix of clethodim 7.5%+ haloxyfop-methyl 15%(Fine 22.5% EC). The treatments were applied at 21 and 35 days after sowing (DAS) and hand hoeing was applied as well. Biomass (fresh weight gm-2) of broad-leaved, grass, and total weeds in sesame field were determined during the summer seasons 2020 and 2021. The results showed in both seasons that all weed control treatments reduced weed biomass while increasing yield components. Higher weed control efficiency was observed with post emergence application of clethodim, cethodim+ haloxyfop-methyl followed by hand hoeing. Pre emergence application of pendimethalin 0.75 kg ha(-1) followed by post emergence application of quizalofop ethyl 0.0050 kg ha(-1 )was found to be the better treatment to control the weeds in broadcasted sesame. Also, application of pre-and post-emergence herbicides recorded significantly lower fresh weight of all weeds. A significant increase in all agronomic traits of sesame yield such as No. of branches/Plant, No. of capsules/Plant, No. of grains/capsules, 1000 grains weight (g), grain yield (kg/4200 m2), stalk yield (kg/4200 m(2)) and straw yield) were recorded with all treatments when compared to untreated control during the two seasons 2020 and 2021. Moreover, there was no significant (p <= 0.05) difference in chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids levels between all herbicides or between the two-hand hoeing and unwedded control. Interestingly, no phytotoxic symptoms appeared on sesame leaf pigments in response to herbicide application. Also, the side effect of herbicides on subsequent crops was investigated and the results revealed no harmful effect due to residual effect from any of the tested herbicides to seed germination percentage of barley and green beans.