Effect of intra-row spacing on yield and quality of some onion varieties (Allium cepa L.) at Aksum, Northern Ethiopia

Lack of improved varieties and production practices have been the major bottlenecks of onion production and productivity in Tigray, particularly at Aksum area. There have been no recommended intra-row spacing and variety for that area specifically; rather farmers used to practice non-uniform plant spacing. Thus, a field experiment was conducted to investigate the influence of intra-row spacing, variety and their interactions on yield, shelf life and bulb quality of onion, thereby recommend the optimum practices to farmers in the study area. The study was conducted between August 2010 and April 2011 at Aksum area (L/maichew district). Three different intra-row spacings (5, 7.5 and 10 cm) were evaluated using four varieties of onion (‘Adama’ Red, ‘Bombay’ Red, ‘Melkam’ and ‘Nasik’ Red) using RCBD replicated four times. Data on yield and quality parameters were recorded and subjected to ANOVA. Results indicate that intra-row spacing of 10 cm was superior in plant height, leaf number per plant, leaf biomass yield, leaf dry matter content and percentage of bolters. Highest total bulb yield was recorded at the closest intra-row spacing (5 cm) followed by 7.5 cm. ‘Melkam’ variety was the highest yielder, while ‘Adama’ Red was the lowest yielder. Average bulb weight increased with increasing intra row spacing. ‘Melkam’ variety followed by ‘Bombay’ Red variety was superior in average bulb weight. ‘Adama’ Red recorded the highest unmarketable yield. Key words: Intra-row spacing, yield, quality, onion varieties, spacing.