The effects of application of Paraquat chemical drying on seed yield of Crimson clover cultivar Alborz 1

In order to investigate the effect of Paraquat herbicide on induced drying of plants and therefore, early harvest of crimson clover seeds in Alborz 1 cultivar a factorial experiment was conducted using a randomized complete block design with three replications, and 12 treatments for two cropping seasons 2012-2013 and 2013-2014. The first factor was different dosage of Paraquat consisted of four levels (a1= no herbicide, a2= 50% less than recommended dose (2 litreha-1), a3= recommended dose (4 literha-1) and a4= 50% more than recommended dose (6 litreha-1) and the second factor was phonological stage of the plants when Paraquat herbicide was applied consisted of three levels. (b1= Physiological maturation of seed, b2= 50% browning of the inflorescence, b3= complete inflorescence browning). Results showed that different amount of Paraquat in all three phenological stages had significant effects on seed yield, number of seeds per in florescence and 1000-seed weight compared to the control treatment with no use of herbicide. Result of the two-years study showed that a3b2 treatment with seed yield of 585.83 kgha-1 had the highest seed yield. However, there was no significant difference between application of 2 and 4 liters of Paraquat (Gramoxone herbicide) per hectare at the browning stage of 50% of inflorescences. Therefore, a2b2 treatment with seed yield of 585 kgha-1 and near 25% increase compared to the control is recommended for seed production of crimson clover Alborz 1 cultivar in Karaj region.