Wild sunflower interference in common bean fields in the Central Rift Valley of Ethiopia

Abstract

The wild sunflower, an invasive alien species, is known to affect the performance of field crops. A field experiment was conducted to estimate the effects of different levels of wild sunflower and common bean densities on common bean yield components and grain yield, as well as to quantify yield loss due to their competition at varying densities. The experiment was laid out in a randomized complete block design in a factorial arrangement with four replications. Hence, factorial combinations of three common bean densities and five wild sunflower densities were tested at two locations. At 24 plants m−2, wild sunflower had maximum dry biomass of 413.84 and 549.83 g−2 at Adamitulu and Melkassa, respectively. An increase in wild sunflower density from 0 to 24 plants m−2 resulted in a reduction of pods per plant up to 62.41% and 83.11%, respectively, at Adamitulu and Melkassa. Compared to the weed‐free plot, the highest wild sunflower density (24 plants m−2) had a 4.6‐fold reduction in seed per pod. Weed‐free plots at Adamitulu and Melkassa yielded the highest grain yields of 2.77 and 3.37 t ha−1, respectively. Common bean grain yield reduced by 88.12% and 67.64%, in Adamitulu and Melkassa, due to the highest density of wild sunflower. The rectangular hyperbolic equation fits common bean grain yields well. This study, hence, proposes that wild sunflower plants be kept at a density of no more than three plants per meter square to minimize severe yield loss and help common bean growers make decisions on wild sunflower control.