Foliar Application of Selenium and Zn to Improve the Yield and Yield Components of Rapeseed Genotypes under Conventional and Delayed Sowing Dates

A two-year trial (2014-2016) was carried out to investigate the response of rapeseed genotypes to foliar application and sowing date in Karaj, Iran.

Factorial-split plot arrangement of the treatments was set up as a randomized complete block design with three replications. The first factor consisted of three sowing dates of 7 October (well-timed sowing) 17 October, and 27 October (delayed), the second factor consisted of four levels of foliar application with pure water (control), selenium (1.5%), Zn (1.5%), and selenium and Zn (1.5%), and the third factor was the five genotypes including Ahmadi, SW102, Okapi, GKH2624, and GK-Gabriella. Sowing date and foliar application were factorial in main plots and genotypes as split plot in subplots.

Number of silique per plant, number of grain per silique, length of silique, grain weight, biomass, and grain and oil yields were significantly affected by the sowing date, foliar application, and genotype. Among the foliar application treatments, results showed that the highest grain and oil yields with an average of 3692 and 1512 kg.ha-1 were related to selenium and Zn, respectively. The average grain and oil yields of rapeseed genotypes decreased by 45.7 and 49% on 17 October and by 52.5 and 52% on 27 October compared to 7 October.

The results indicated that GK-Gabriella genotype sown on 7 October and GKH2624 genotype sown on 17 and 27 October treated with selenium and Zn could produce the highest grain and oil yields under Karaj climate condition.