الملخص الإنجليزي
Growth and yield of chickpea (Cicer arietinum L.) in response to sowing dale and plant population were analysed in terms of interception and utilization of photo synthetically active radiation (PAR). The amount of PAR intercepted by each treatment was estimated from the measured leaf area index. The relationship between total dry matter. seed yield and accumulated intercepted PAR was linear. The average efficiency of radiation utilization for total dry matter was 1.56 g.MJ-1 during the seasons. Yield differences between treatments were due to the amount of PAR, its efficiency of utilization or both. Early sowing increased the amount of intercepted PAR (31-33%) by enhancing the size of the canopy early in the season. The radiation utilization efficiency of seed yield was higher for late sown crops compared to early sown crops. However, the higher efficiency of utilization in late sowing was insufficient to compensate for the significantly lower amounts of intercepted PAR. Higher plant populations increased both the total dry matter and the seed yield due to higher radiation interception and utilization.
