Evaluation of response of rapeseed cultivars to reduced growth season

In order to accessing an approach to reduce of water use in the agriculture, a two-year study was carried out as split plot based on a randomized complete block design with three replications at Torogh Agricultural Research station in Mashhad. Sowing dates (3 sowing dates in first year and 5 sowing dates in second year) and cultivars (Hayola-308, Hayola-401, RGS003 and Zarfam) of rapeseed were considered as main and sub plots, respectively. Results showed that by reducing the growth season (delaying in planting date), seed yield and most of the yield components of rapeseed cultivars such as plant height and 1000-seed weight decreased compared to the autumn sowing date. Maximum seed yield of dormant (entezar) culture for Hayola-401 cultivar was 3611 kg/ha which decreased by 23.3% compared to highest seed yield in autumn planting date for Zarfam cultivar (4708 kg/ha), although this decrease was not significant. However, in dormant culture and for some cultivars, the potential of seed yield seems appropriate, especially if the benefits of removing three autumn irrigations are also considered. Based on the results of this experiment, optimal selection for planting date of rapeseed by eliminating autumn irrigation is dormant culture. Planting compatible cultivars with these conditions is also the next priority to ensure the success of production and in this regard, early spring cultivars such as Hayola-308 and Hayola-401 are preferred to other cultivars due to greater adaptability to reduced growth season and higher seed yield in these conditions.