Influence of Bulb Treatment and Spacing Patterns on Yield and Quality of Onion (Allium cepa var. Cepa) Seed at Humbo Larena, Southern Ethiopia

Field experiment was conducted at Humbo Larena, wolaita zone during the 2012/2013 dry season, to study the effect of bulb treatment and spacing patterns on seed yield and quality of onion in the semi-arid zone of Ethiopia. Treatments consisted of a factorial combination of four levels of bulb types [whole bulbs, cut (topped) bulbs, ash-treated cut (topped) bulbs, and fungicide-treated cut (topped) bulbs] and four levels of spacing patterns (50 x 30 x 20 cm, 60 x 30 x 20 cm, 40 x 20 cm, and 50 x 20 cm) laid out in randomized complete block design replicated three times. The onion variety known as Bombay Red was used as a test crop.  Results revealed that both the main as well as the interaction effects of bulb treatment and spacing patterns did not influence the number of days required for emergence, 1000 seed weight, and physical purity.  Days to 50% flowering was significantly influenced by bulb treatments but not spacing patterns. The main effects of both bulb treatment and spacing significantly influenced, plant height, number of umbels per plant, umbel diameter, seed weight per umbel, standard germination, vigour Index I and vigour index II. Bulb treatment and spacing interacted to significantly influence percent stand count, number of flowering stalks per plant, and seed yield. The highest seed yield was obtained in response to planting fungicide-treated topped bulbs at the both double-row spacing. However, significantly higher values of all seed quality parameters were obtained from both single-row spacing. Keywords: Onion ( Allium cepa var. C epa ), bulb treatment, spacing patterns, Ethiopia