[Effect of population density on the behaviour of three faba cultivars (Vicia faba L.) [Portuguesa INIA, Morada, Blanca] in the coastal dryland central zone of the country]

The effect of population density on the performance of three faba bean (Vicia faba L.) cultivars in the central coastal dry lands was evaluated. The experiment was conducted at La Estrella locality, VI Region. Portuguesa INIA, Morada and Blanca cultivars were used under six populations densities. The treatments were arranged in a split plot design with randomized blocks and three replications. Samplings were done every fourteen days, and then a yield evaluation and growth analysis were made. Most of the cultivars reached the maximum Leaf Area Index (LAI) and Crop Growth Rate (CGR) values from 131 to 145 days after sowing, regardless of the population density. The highest LAI values were obtained at the greatest densities, while greatest the Net Assimilation Rates (NAR) were reached in the lowest densities. No significant differences were observed in green pod yield among cultivars nor in densities, whereas in grain yield, the productivity was only significantly lesser at lower densities in the Morada cultivar. Portuguesa INIA and Blanca did not show substantial differences among the different population densities studied. Faba bean growing for dry grain with the Portuguesa INIA cultivar proves an excellent alternative for the central coastal dry land since adequate grain size and weight are obtained to meet the export requirements (55,5% grains with exportable size). For green pod production, the Morada cultivar with 15 pl/m2 would bring the best marginal return rate with 1.138%; Portuguesa INIA with 30 pl/m2 appears as the best alternative for dry grain production since it represents the highest marginal return rate with 319%. However, due to hydric stress suffered by plants in the grain fill stage and the high cost of using 30 pl/m2, it seems advisable to evaluate this information in a new season before attempting a definitive recommendation in this regard