Trait associations in onion grown under organic and mineral fertilization

Abstract

The aim of this two-year field study was to investigate the effects of different nutrient regimes on the interrelationships of onion (Allium cepa L.) yield and yield contributing characteristics (bulb weight, number of bulbs plot-1, plant height and number of days from sowing to emergence). The experiment involved five onion cultivars grown in conventional (mineral fertilization) and organic (unfertilized, bacterial fertilizer, farmyard manure) production systems. The trait associations were studied using a twodimensional biplot. The applied treatments affected all the traits investigated and the effects were stable across the growing seasons. Consistently positive correlations found among yield, bulb weight, number of bulbs plot-1 and plant height suggested that taller plants performed better in all nutrient regimes. Early emergence correlated positively with yield only in favorable (mineral and bacterial fertilizer) environments. The close position of the two favorable entities on the biplot imply the possibility of achieving high and stable onion yields by applying an appropriate organic amendment.