Relative competitiveness of soybean cultivars with barnyardgrass

Abstract

ABSTRACT:The aim of this work was to evaluate the competitiveness between soybean cultivars and barnyardgrass, based on morphological and physiological characteristics of species. The experiments were conducted in completely randomized experimental design, with 4 replications. therefore, the ability of one species to interfere on another is equivalent.For plant height, barnyardgrass displays higher competitiveness compared to BMX Apolo RR, with early cycle and short height. The intraspecific competition is more important to barnyardgrass than interspecific competition with soybean cultivars, resulting in negative effects on the morphological and physiological characteristics of species.

Effect of high temperature and recovery from stress on crop–weed interaction

“…Similar result was found in barnyardgrass (Echinochloa crus-galli L., C 4 pathway), which exhibited higher HEI than the soybean 'BMX Apolo RR' , a short-stature cultivar, whose cycle is very precocious; this fact showed its high competitiveness, by comparison with the crop (Bastiani et al 2016). A study of soybean competing with goosegrass (Eleusine indica L.) (C 4 ) showed values that were close to the hypothetical ones; thus, plants did not interfere with each other in terms of HEI .…”

Interference and Economic threshold level of Alexander Grass in Soybean as a Function of Cultivars and Weed Populations

“…The lower competitiveness of these cultivars may occur due to the slower initial growth, allowing a higher incidence of sunlight on weeds. Consequently, occur loss of competitiveness, a fact also related by Bastiani et al, (2016) when working with soybean cultivars living with barnyard grass. 1 i and a: productivity losses (%) per unit of alexandergrasss when the variable value approaches zero or tends to the infinity, obtained by the equation Y= (i.X)/(1+( i / a).X); respectively; * Significant in p≤0,05.…”

“…For any agricultural crop, the productivity is dependent on many factors, such as those already reported previously, and when it comes to soybean, this productivity is much below than those obtained in experimental areas or crops that adopt high technologies. Among the probable causes for this low productivity are the factors of production, such as cultivars, soil fertility, insect management, diseases and weeds, related in such a way that any of them can be limiting to the production (Bastiani et al, 2016). The negative effects of weed interference are manifested on the quantity and quality of agricultural production in consequence of competition for environmental resources, allelopathy, or for being agents that host pests and diseases (Kalsing and Vidal, 2010;Galon et al, 2011).…”

“…Weeds compete with crops for the resources available in the environment, such as: water, light and nutrients (Bianchi et al, 2006;Bastiani et al, 2016), Gal et al (2015), when studying the effect of red light reflection by weeds on soybean, concluded that the crop presented a decrease in root volume, nodulation, root length, among other factors related to gene expression and flavonoid production For the control of weeds, especially the alexander grass that infests soybean and other annual and perennial crops, we use herbicides in function of the practicality, efficiency and lower cost when compared to other methods of control (Christoffoleti et al, 2006). However, the use of herbicides has generated environmental contamination and also in the food produced, thereby necessitating other forms of weed management in soybean, such as cultural, preventive, biological, mechanical management, among others methods.…”

Weed Species Association in Arable Fields: Old Approach, New Application

“…The relationship between weed species and crops in arable fields is explored by several authors in terms of competitive aspects and crop yield losses (Bastiani et al , 2016; Franco et al , 2017). However, only recently the interactions within the weed community in arable fields are gaining importance in weed science (Adegas et al , 2010; Santos et al , 2017).…”