Effects of planting date and nitrogen rates on agronomical traits of potato Var Markiz

In order to study of planting date and nitrogen rates on agronomical traits of potato Var Markiz, an experiment was conducted in the farm research station’s of Arak Islamic Azad University, Iran in 2008. The experiment was factorial based on RCBD with four replications. The treatments composed of planting dates in three time, 21 June, 8 July and 22 July and nitrogen rates in four levels: 46, 80, 115 and 150 kg/ha. Results showed that, that effect of planting dates on tuber yield was significant. The maximum yield by 19.5 t ha-1 was obtained from 21 June planting date. Interaction of planting date and nitrogen rates on tuber fresh weight, tuber dry weight, number of tubers per plant, number of small and large tubers per plant, diameter size of tuber and tuber yield were significant. The highest yield by 24 t/ha was related to 21 June planting date with 150 kg/ha nitrogen.