Effect of Seed Priming with Potassium Nitrate on Bulb Yield and Seed Quality of Onion (Allium Cepa L.), under Rift Valley Conditions, Central Ethiopia

Abstract

Laboratory and field experiments were conducted to study the effects of seed priming using different concentrations of potassium nitrate on bulb yield and seed quality of onion (Allium cepa L var cepa.). In laboratory experiment, factorial combination of four concentrations of KNO₃ salt [(0% (distilled water), 1%, 2% and 3%)] and four priming durations (12 hrs, 24 hrs, 48 hrs and 72 hrs), with one control treatment of un-primed seeds were laid out in RCBD with four replications. Field experiment consisted of the same combinations as set in the laboratory experiment and the experiment was laid out as a RCBD in a factorial arrangement with three replications. Data were collected on marketable bulb yield, unmarketable bulb yield, total bulb yield, standard germination, rate of germination, vigour index-I, vigour index –II, and seedling dry weight. Analysis of the data revealed that Effect of concentration was significant at (p<0.05) for seed germination, seedling vigour and, onion bulb yield. Similarly, interaction of Concentration of the salt and priming duration were significant at (p<0.05) for standard germination, rate of germination, vigour index II, seedling dry weight, and bulb yield. These parameters were significantly increased in response to the priming duration of 12 hrs for standard germination, rate of germination, and vigour index. However, the lowest results on these parameters were recorded for the duration of 72 hrs for priming with the potassium nitrate salt. The treatment combination involving priming seeds with 3% KNO₃ for 72 hrs produced the lowest standard germination, rate of germination, and vigour index. For the field experiment, the highest marketable bulb yield (40.78 tons/ha) and total bulb yield (47.78 tons/ha) were obtained in response to priming the seed with 1% KNO₃ for 12 hrs compared to the yields obtained in the control treatment which was 35.11 tons/ha. In conclusion, priming onion seeds with 1% KNO₃ solution for a period of 12 hrs as well as priming the seeds with distilled water for 72 hrs significantly enhanced onion seedling performance and the yield of marketable bulbs.

Keywords

• Bulb yield
• Concentration
• Duration
• Onion
• Potassium nitrate
• Priming

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