Effect of transplanting date and reduced doses of oxyfluorfen herbicide on weed control, yield and quality of onion (Allium cepaL.) in south of Iran

Abstract

In order to evaluate the effects of transplanting dates (7 October, 22 October and 6 November) and weed control treatments (50, 75 and 100% of recommended dose of oxyfluorfen herbicide and hand weeding) on weed control, bulb yield and quality of onion cv. Rio Bravo, a split plot design experiment was conducted in Minab (Hormozgan province) in 2013–14. The results showed that apart from hand weeding treatment with no weed in plots, oxyfluorfen application at 100% recommended dose caused the minimum density and dry weight of weeds. Besides weed control, oxyfluorfen application caused increase in yield, weight and dimension of bulbs and decrease in their neck thickness. The interaction between transplanting dates and weed control methods was significant for bulb yield and quality characters, so that the highest yield of bulbs (80.6 t ha−1) was obtained with application of oxyfluorfen at 75% recommended dose in 22 October planting date, although 100% recommended dose of this herbicide in all planting dates also produced high yields without significant differences. The highest content of total soluble solids (6.46%) and lowest neck thickness (8.5 mm) of bulbs were observed in oxyfluorfen 100% recommended dose and 6 November planting date. Since hand weeding is an expensive and labor intensive process, so the complete dose of oxyfluorfen is recommended for weed control and high yield in onion, although with proper selection of planting date, the use of reduced dose (75%) of this herbicide is also possible.