Competitive Ability of Rice Cultivars in the Era of Weed Resistance

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 occur - rence 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 physiologi cal traits as a function of environment-friendly crop practices. on their biological and morphological traits to optimize management strategies. Germination and emergence patterns, dry mass, dry mass accumulation, plants height, number of tillers or branches, number of inflorescences other variables often for future estimations