Seed Filling Trend of Faba bean (Vicia faba L.) as Affected by Planting Date and Density

To investigate the effect of planting date and plant density on phenology, seed yield, its components, seed filling rate and grain filling period of faba bean, a factorial experiment based on randomized complete block design with four replications was conducted at Research Farm of Agricultural Sciences and Natural Resources of Gonbad University, Iran, during growing season of 2012-2013. The factors were three planting dates (4th of November, 4th of December 2013 and 3th of January 2014) and four planting densities (8, 12, 16 and 18 plant/m2). The results showed that planting dates significantly affected on phenology, yield and its components, seed filling rate and periods while the effect of plant density on seed filling period was not significant. Comparison of sigmoid equation coefficients showed that seed filling rates in three planting dates were different. The highest seed filling rate was obtained in 3th of January and the lowest at November 4, planting dates. The effect of planting date on seed filling duration was also significant, but it was not on plant density. Regression analysis showed that increasing 0.01g seed growth rate in seed unit, resulted in seed weight increase by 45.11, 32.43 and 26.66 g for November 4, December 4 and January 3 planting dates respectively. Delaying planting dates decreased seed filling period by 8.53 days and seed weight by 0.27 g. due to its effect on day length and temperature changes. Delayed planting dates were more effective on the rate and period of seed filling and phenology of faba bean. Delaying in planting date increased time to emergence, while decreased seed filling period and seed yield because of coincidence of this period with high temperatures.