Influence of different population densities of Portulaca oleracea L. on growth and yield of transplanted onion Allium cepa L.

Abstract

Portulaca oleracea is one of the weeds of onion in the Philippines. Its negative impact on growth and yield, however, has not been quantified. An experiment was conducted to determine the influence of different density levels of P. oleracea on growth and yield of transplanted onions. The weed was allowed to grow with the onion at 0, 5, 10, and 15 plants 176 cm-2 from the day of planting until harvest. The experiment was arranged in randomized complete block design with four replications. Growth and yield of transplanted onions were influenced by different densities of P. oleracea. The fresh weight of bulbs was reduced by 32.7, 51.3, and 73.6%; the dry weight by 39.6, 59.8, and 71.9% when the weed competed at 5, 10, and 15 plants 176 cm-2, respectively. Correlation and regression analyses showed that the population density of P. oleracea were strongly, negatively correlated as well as it influenced by 98.54 and 93.45%, respectively, on the fresh and dry weight of transplanted onion. This study confirmed that P. oleracea is truly a weed of transplanted onion implying that it could potentially reduce yield if left unmanaged throughout the crop’s growing cycle. Thus, it must be managed effectively whenever seen infesting transplanted onions in the country. Although the results were obtained only under screenhouse conditions, the findings suggest the need to develop a holistic weed control strategy against the weed.