Abstract:
Shallot (Allium cepa L. var ascalonicum Backer) is one of the alliaceous crops grown in
Ethiopia using bulblets due to difficulty in true seed production. Application of gibberellic
acid (GA3) is used to partially augment vernalization requirements of biennial crops and
induce early flowering. Potassium nutrient is also known to play several physiological and
biochemical processes in plants, which can have direct and indirect consequences on crop
productivity. Hence, field experiment was conducted to assess the effects of GA3 and
potassium fertilizer (KCl) on seed yield and seed quality of Improved Huruta shallot variety at
Haramaya University during the 2020 cropping season. The treatments comprised 4 x 4
factorial combinations of GA3 (0, 100, 200 and 300 ppm) and potassium rates (0, 75, 100 and
125 kg ha-1 KCl) using RCBD design with three replications. Seed quality test was conducted
in CRD with four replications. The result of analysis of variance show growth, seed yield
components, seed yield and seed quality parameters of shallot were significantly influenced
either by one or both GA3 and KCl treatments. Days to bolting, 50% flowering, seed maturity,
seed per umbel, seed weight per umbel and seed yield, and, except for the physical quality, all
seed quality parameters were significantly affected by the interaction of GA3 and KCl
fertilizer. Improved Huruta shallot variety produced the highest seed yield of 797.5 kg ha-1
with highest germination of seeds (99.4%) from the application of 100 ppm GA3 and 100 kg
ha-1KCl fertilizer. The highest seedling fresh weight (195.6 mg) was found in plants that
received a mixture of 300 ppm GA3 and 100 KCL fertilizers whereas the lowest (101.7 g) was
recorded in plots that received 100 ppm GA3 and 0 KCL. The maximum seedling dry weight
(19.97 mg) was obtained in Improved Huruta shallot that received 100 ppm GA3 and 100 KCL
fertilizers whereas the lowest (15.5 g) was recorded in plots that received no GA3 and KCL
fertilizers. This treatments combination had the highest marginal rate of return (16133.65%),
benefit cost ratio (112.73) and net benefit (3557194.39 Birr). Thus, it is possible to conclude
that application of 100 ppm GA3 with 100 kg KCl ha-1 could be productive and attractive for
farmers since it produces the highest seed yield coupled with highest marginal rate of return,
benefit cost ratio and net benefit.
