Competitive Ability of Rice Cultivars in the Era of Weed Resistance

Abstract

Almost all plants are negatively affected by neighboring plants, which impose some degree of competition within the population, depending mainly on the quantity and quality of natural resources available in the environment. In rice cultivation, the occurrence of a high and diverse infestation of weeds results in high competition levels among the species. In addition, the high and growing number of cases about herbicide-resistant weeds, especially the widespread distribution of Imidazolinone-resistant weedy-rice and the high infestation of weeds belonging to the Echinochloa genus, has increased the competition levels within rice cultivation due to the lack of control. Therefore, the inclusion of rice cultivars with greater competitive ability represents a promising tool for weed management, since new cases of resistance to herbicides are often reported and alternative control strategies are scarce. The use of rice cultivars with a greater ability to suppress weeds can alleviate the competitive effect of these species, giving priority to the crop for the use of environmental resources due to the faster occupation of the ecological niches. Thus, this chapter aims to explore the competitive ability of rice cultivars against troublesome weed species, accounting for the role of their morphological and physiological traits as a function of environment-friendly crop practices.

Contribution For Improvement Of Rice Breeding Programs Through Morphoanatomical Traits

“…On the same way, superior tillering in rice plants may increase its competitive ability against weeds (Galon et al, 2015), and possible volunteer plants of other rice varieties (Schreiber et al, 2018), and increase the use efficiency of environmental resources (Nawaz & Farooq, 2017). Vigorous tillering also allows rice to reach high leaf area index (LAI) earlier in the crop cycle, depending on N availability (Zhong et al, 2002).…”

Factors affecting incidence of narrow brown leaf spot of rice caused by <i>Passalora janseana</i>

“…Weeds among crops have been reported in increasing the disease incidence by the competition on crops acting as a pest itself; while being a vector of a pathogen or a reservoir of a pathogen or its vector is very common (Wisler, 2009). Dual role of weeds; one by weakening crop via competition for resources and second by being an alternative host for pathogens, the probability of pathogen infections has been enhanced in rice fields all over the globe (Schreiber et al, 2018). The density of rice filed, especially in a broadcasted field, the seeding rate shows a great impact on the incidence of disease with diversified microclimate.…”

Effect of Nitrogen fertilizer, weed control and seed rate on incidence and severity of narrow brown leaf spot in rice cultivation under the dry zone of Sri Lanka

“…These unwanted plants can significantly influence disease incidence by acting as pests, serving as an alternative host for pests, pathogens, and vectors (Wisler 2009). The crop has to compete with the weeds for resources subsequently weakening and increasing the probability of pathogen infection (Schreiber et al 2018). It is recommended to remove weeds in the field in order to remove alternative hosts of the fungus, Cercospora janseana since the presence of weeds in the field has a direct impact on the NBLS.…”