Effect of Detopping and Plant Density on Yield and Yield Components of Barakat Cultivar of faba bean (Vicia faba L.) in Gonbad Kavous

Detopping in some plants reduces vegetative growth and increases transporting of photosynthate materials to specific sinks such as seeds. To study the effects of detopping removal and plant density on yield and yield components of faba bean (Vicia faba L.), an experiment was carried out as a factorial arrangement based on a randomized complete block design with three replications at farm research of Gonbad University in 2009-2010. The detopping factor performed at before flowering, beginning of flowering, pod setting and none removal. Plant density included four levels of 4, 6, 8 and 10 plants m^-2. Results showed that the effects of top removal and plant density on number of pods/plant, number of seeds/pod, number of seeds/plant, 100-seed weight, plant yield, seed yield/ha, pods coat weight and seeds weight/pods coat weight were significant at the 1% level. Maximum number of pods/plant and pods coat weight belonged to top removal at pod setting stage; whereas the maximum number of seeds/pod, 100-seed weight and seeds weight/pods coat weight belonged to top removal at before flowering; number of seeds/plant, plant yield and seed yield/ha obtained from top removal at flowering. The density of 4 plants m^-2 had the highest number of pods/plant, number of seeds/pod, number of seeds/plant, 100-seed weight, plant yield, pods coat weight and seeds weight/pod coat weight, whereas the highest seed yield/ha belonged to the treatment of 10 plant m^-2. This study showed that the best time for detopping of faba bean was at the beginning of flowering and optimum plant density was 10 plants m^-2 that produced the maximum yield.