Determining Planting Time and Seed Rate of Spring Oilseed Rape (Brassica napus L.) In Tabriz Plain

The present research was done in order to determine the suitable planting date and seed rate and to evaluate the seed and oil yields and chlorophyll rate of spring oilseed rape in Tabriz plain climate (cold and semi-arid in the Copen climate classification system). The experiment was conducted as split plot based on a RCBD design in 3 replications with two factors including sowing date (30 March and 9 and 19 April) and seed rate (4, 6, 8 and 10 Kg seeds per hectare). The RGS003 as adapted and superior genotype was used for cultivation. The study was carried out in East Azarbaijan Agriculture and Natural Resources Research and Education Center (Khosrovshah station) during the 2018 year. The results indicated that plants in the 30 March planting date had significantly higher values of field ground cover percent, Leaf chlorophyll index, plant height, pods per plant, 1000 seeds weight, seed oil percent and seed and oil yields. Having sufficient time for growth and establishment, these plants produced higher yields via maximum use of environmental factors. Correlations among the field ground cover percent, Leaf chlorophyll, plant height indices, with each other and seed yield components (except seeds in pod), seed and oil yields were significantly positive. These indices had an important role in yield determining. Finally, the most seed and oil yields including 1673 and 694 Kg.ha-1 respectively, were achieved from 30 March planting date with 6 Kg.ha-1 seed rate for RGS003 as spring cultivar at Tabriz plain.