Interference of Broadleaf Buttonweed and White-Eye in Soybean

Abstract

Weed species is one of the factors contributing to grain yield losses due to crop-weed competition. Two of the most common weeds of soybean fields in Brazil are from the Rubiaceae family: Borreria latifolia and Richardia brasiliensis. This study aimed to evaluate the effects of B. latifolia and R. brasiliensis on plant development, yield components, and soybean productivity. Two assays were conducted in a randomized block design with four replications, using a two-level factorial design, in which the first factor consisted of the species B. latifolia and R. brasiliensis and the second factor consisted of the densities 0, 2, 4, 6, 8, 10, and 12 plants m-2. Plant height, leaf area and total chlorophyll in the V6 and R5 stages, number of pods per plant, number of grains per pod, 1000-grain weight, and grain yield loss were evaluated in both cultivars. Grain yield of both soybean cultivars was negatively affected by the interference with B. latifolia and R. brasiliensis. The species B. latifolia was more competitive with soybean when compared to R. brasiliensis, causing higher reductions for all variables. Each B. latifolia plant per square meter is able to reduce the yield of soybean by 3 a 4.4%, while each R.brasiliensis plant reduces yield by 2 a 2.6%. For both species, the reduction in soybean yield due to competition was caused by a decrease in the number of pods per plant, number of grains per pod, and 1000-grain weight.

Competitive ability of soybean cultivars with Ipomoea indivisa

“…The soybean cultivar DM 66i68 showed concave lines for RP and TRP, both for LA and DM, and values less than 1 in all simulations performed, which demonstrates its genetic differentiation in relation to the other cultivars (Table 1). Differentiation in competitive ability when involving soybean cultivars with weeds was also observed in early-cycle and late-cycle soybean cultivars (SOUZA et al 2019), and between soybean cultivars V-TOP RR and BMX Ativa RR (DIESEL et al 2020). Furthermore, HAMMER et al (2018 found that, among 40 soybean cultivars, the most modern and with the highest production capacity were more competitive in relation to older cultivars in a highly competitive environment.…”

Interference and threshold level of Sida rhombifolia in transgenic soybean cultivars

“…Weeds can cause significant losses if not properly managed. Competition losses can vary from 2-94% depending on factors such as soybean cultivars, weed densities and species, emergence times, and edaphoclimatic conditions (14,19,29,32).…”