Otitoloju Kekere , Augusta Omolara Ogbedebi , Olumakinde Akinbuwa , Yetunde I. Bulu , Taiwo Ekundayo

Department of Plant Science and Biotechnology, Faculty of Science, Adekunle Ajasin University, Akungba-Akoko, Ondo State, Nigeria
Author    Correspondence author
Molecular Soil Biology, 2024, Vol. 15, No. 5   
Received: 06 Aug., 2024    Accepted: 18 Sep., 2024    Published: 08 Oct., 2024

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Scarcity and high cost of onions in Nigeria might be connected to production still largely limited to the field in the north where weather condition is most favorable to it. Its cultivation under screenhouse conditions requires knowledge of optimal watering regime; hence, watering frequency was investigated on onion. Plants were raised in polyethylene pots filled with 9 kg top soil and exposed to wet conditions: watering daily (W₀), 3 times/week (W₁) and once/week (W₂); drought conditions: watering once/1½ weeks (W₃) and once/2 weeks (W₄); or waterlogged condition: planted in water-saturated soil (W₅). Except waterlogging, soil was watered to field capacity in perforated pots. Plant height and number of leaves were reduced by 68.53% and 70.15% respectively at W₅. W₅ also reduced shoot fresh weight, root fresh weight, shoot dry weight and root dry weight from 38.42 g to 19.41 g, 14.00 g to 2.60 g, 6.01 g to 1.31 g, and 3.56 g to 0.73 g respectively relative to W₀. Growth reduction considering plant height with fresh and dry weights of plant parts increased with increasing severity of drought, with the highest at W_4. Yield in terms of number of bulbs and bulb size were optimal at W₁ and W₂ relative to other treatments. Except nitrogen free extract, bulb proximate composition was highest under W₁. Except Ca and Mg, nutrients were highest under W₁.  Relative to W₀, W₅ reduced bulb nutritional and proximate compositions. Onions’ optimal production can be achieved under wet conditions, partially in drought but poorly under waterlogging.

Onion; Water stress; Irrigation; Yield