Title : Effects of bulb size and storage duration on yield and seed quality of onion
Abstract:
Onion is a potential crop in Ethiopia; however, its production and seed quality are low due to inappropriate bulb size and storage time utilization. Thus, an experiment was conducted at Melkassa Agricultural Research Center during 2021/22 and 2022/23 cropping years to investigate the effects of bulb size and storage duration on seed yield and seed quality of onion under irrigated conditions. The experimented two factors: four bulb sizes (20-50 g, 51-80 g, 81-110 g, 111-140 g) and four storage durations (10, 20, 30 and 40 days) using Nafis onion variety. The experiment consisted of 16 treatment combinations which were laid out in a factorial randomized complete block design (RCBD) in three replications on plot size of 3m length by 3m width. Analysis of variance revealed that bulb germination, number of leaves per plant, plant height, scape height, number of umbel per plant, number of umbel per plot, number of flowered and unflowered umbels per plot, umbel diameter, seed yield per plant, seed yield per hectare, seed germination percentage, seed vigor indexes I and II were significantly influenced by the interaction effects of bulb size and storage duration during both years. However, seed weight per umbel, seed physical purity, thousand seed weight and speed of germination were significantly influenced by the main effects of bulb size and storage duration during both cropping years. Growth, yield and quality characters of onion seed were gradually increased with an increased in bulb size. The maximum number of umbel per plant, umbel diameter, number of umbel per plot and the highest number of flowered umbel per plot were obtained from bulb size three (81-110g) planted at 30 days storage duration at both years. On the other hand, the highest seed yield per plant (32.62g and 32.51g), seed germination percentage (93.33% and 90%), seed vigor indexes I (1229.7 and 1200) and II (16.22 and 18) were obtained from the largest bulb size four (111-140 g) planted at 20 days storage duration during 2021/22 and 2022/23, respectively. However, significantly the lowest values were recorded from smallest bulb size (20-50g). Based on the finding of the current study treatment combination of largest bulb size four (111 -140g) with a storage duration of 20 days is appropriate for better seed yield and seed quality in onions under irrigated conditions of Melkassa done for two seasons. Therefore, onion seed producers in the study areas should be encouraged to plant largest bulb size four (111 -140g) at 20 days storage duration to produce better yield and quality of onion seed.
Keywords: Bulb size; Umbel; Seed weight; Germination; Quality seed; Seed vigor
