Effect of Single Irrigation on Yield and Agronomic Characters of Spring Rapeseed at Rainfed Condition

To investigate the relationship between grain yield and its components in spring rapeseed crop farming, this study was conducted as split plot arranged in a randomized complete block design (RCBD) with two factors and three replications and two years on spring canola varieties in Maragheh Rainfed Agricultural Research Station. The treatments were four levels of single irrigation amounts (Zero, 30, 60 and 90mm irrigation water use) at growth stages (stem elongation, flowering and seed filling stage). There were positive significant correlations due to grain yield with all agronomic characters. Under single irrigation, path analysis and determination of direct and indirect effects showed that, number of pods per square meter, straw yield and seed number per pod has a direct positive effect and thousand seed weight has a negative direct effect on grain yield. Optimum level of single irrigation for rapeseed was 60mm irrigation at flowering stage that lead to producing 1071kg grain per hectare due to control of soil moisture stress at flowering stage. This treatment affected on grain yield (83% compared to rainfed condition) by increasing growth and produce new pods.