Effect of seed gamma irradiation and nitrogen fertilizer on yield and nitrogen use efficiency for protein production of Chamomilla recutita L.

To evaluate the effect of seed treatment with gamma rays and nitrogen application on yield and nitrogen use efficiency for protein production in Chamomilla recutita L. leaves, a factorial experiment was conducted based on randomized complete blocks design with three replications. Treatments were gamma rays from Cobalt-60 source on chamomile seeds cv. Bodegold (0, 4, 8, 12, 16, and 20 Gray) and different levels of nitrogen (0, 50, 100, and 150 kg/ha). Results showed the significant interaction effect of gamma and nitrogen on the leaf yield, biomass and protein, harvest index of protein, and nitrogen use efficiency for leaf and protein production, the yield of dried flower and essential oil. But gamma irradiation and nitrogen had no significant effect on leaf protein and essential oil percentage. The highest yield of leaf (4194 kg/ha) and biomass (19996 kg/ha) were obtained at 8 GRAY of gamma rays with 100 and 150kg/ha of nitrogen application, respectively. However, the highest yield of protein (571kg/ha) was obtained from 20 GRAY of gamma rays and 0 kg/ha of nitrogen and the lowest yield (151kg/ha) was obtained from 0 GRAY and 50kg/ha of nitrogen. The highest value of nitrogen use efficiency for leaf (67.39) and protein (9.30) production was related to the plants grown from seeds and treated by 16 GRAY of gamma and 50kg/ha nitrogen. The lowest nitrogen use efficiency for leaf (13.94) and protein (1.42) production were observed at 16 GRAY and 150kg/ha nitrogen. The highest yield of dried flower in 0, 4, 8, 12, 16 and 20 GRAY were obtained at 150, 100, 0, 150, 100 and 100 kg/ha of nitrogen application, respectively. Generally, irradiations over the 12 GRAY resulted in reducing the nitrogen application for protein production.