Initial growth and competitive ability of yellow nutsedge and irrigated rice

Abstract

-Weeds cause significant reduction in the irrigated rice crop yield. Cyperus esculentus (yellow nutsedge) is adapted to irrigate environment. Information on the competitive ability of the weed to the culture, and their environmental adaptation, are scarce. In this study, we sought to determine the initial growth and competitive ability of yellow nutsedge and irrigated rice, as a function of cultivar growth cycle. Initial growth and competition studies were conducted in a randomized complete design in a greenhouse in the agricultural year 2010/11. For the initial growth study, the treatments consisted of a factorial combination of a biotype of yellow nutsedge and two rice cultivars in the function of the vegetative cycle (BRS Querência: early cycle -IRGA 424: intermediate cycle) and six evaluation times (10, 20, 30, 40, 50, and 60 days after emergence). Were evaluated: plant height, leaf area, aboveground dry biomass and root dry biomass. In the competitive ability study in the replacement series, the cultivar BRS Querência (early cycle) and yellow nutsedge were utilized and tested in different proportions of competition (100:0, 75:25, 50:50, 25:75, and 0:100). Were evaluated leaf area and aboveground dry biomass. In general, rice cultivars have an adaptive value equivalent to yellow nutsedge. IRGA 424 cultivar has less height than weed, becoming the weed control more important in this cultivar. For rice crop, intraspecific competition is more important, whereas for the weed, interspecific competition is the most pronounced.

Criteria for Decision Making and Economic Threshold Level for Wild Radish in Wheat Crop

“…The observed differences between the results of cultivars may occur due to the best use of the resources available in the environment. Early-cycle cultivars, such as BRS 328, have a rapid initial development and leaf area accumulation and hence intercept light more easily, reducing the incidence of solar energy in their neighbors and increasing their competitive ability against the presence of weeds (Fleck et al, 2003;Westendorff et al, 2013).…”

Comparing Fitness Cost Associated with Haloxyfop-R Methyl Ester Resistance in Winter Wild Oat Biotypes

“…Study and quantification of fitness cost have been performed by various researchers (Lamego et al, 2011;Westendorff et al, 2013). Keshtkar et al (2017) studied the fitness of Black grass (Alopecurus myosuroides Huds.)…”