Influence of plant spacing on yield and yield components of improved onion varieties in Mersa District, North Wollo, Ethiopia

Abstract

This study evaluated the effects of plant spacing and variety on growth and yield of onion in Mersa District, North Wollo, Ethiopia. Treatments consisted of a factorial combination of three improved varieties and six planting spacing arranged in a randomized complete block design with three replications. Analysis of variance revealed that the interaction of spacing and variety significantly affected most growth and yield parameters. The highest marketable bulb yield (44.57 t/ ha) was obtained from the Nafis variety at 10 cm × 5 cm spacing. Maximum yields of Adama and Bombay Red were recorded at 20 cm × 3 cm spacing. The widest spacing produced the lowest yields across all varieties. Results indicate that optimal spacing is variety-specific; closer spacing favored higher productivity, particularly for Bombay Red and Adama, while Nafis performed well across moderate to close spacings. These findings provide practical recommendations to improve onion productivity under similar agro-ecological conditions.