RESPONSE OF SHALLOT (Allium cepa L. var ascalonicum BACKER) TO GA3 AND KCl FERTILIZER FOR SEED YIELD AND QUALITY AT HARAMAYA, EASTERN ETHIOPIA

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.