Cypress round

Cypress round L. represents one of the most persistent and challenging weeds to manage in tropical and subtropical agricultural systems, especially in intensive production contexts such as sugarcane, rice, corn, soybeans, and vegetables. Known in Brazil by common names such as tiririca, tiririca-vermelha, or capim-dandá (and internationally as purple nutsedge, nutgrass, or cocograss), Cypress round It is a perennial sedge that stands out for its ability to infest cultivated areas, roadsides, orchards, and disturbed soils.

Its scientific name Cypress round L. was formally defined by Linnaeus in 1753 in Species Plantarum, with a taxonomic history marked by synonyms such as Chlorocyperus rotundus (L.) Palla, Cyperus agrestis Willd. ex Spreng. & Link et al., reflecting morphological variations and geographic adaptations throughout botanical descriptions. It belongs to the family Cyperaceae, order Poales, class Liliopsida, and is native to tropical regions of Africa, southern and central Europe, and southern Asia, having spread pantropically through tubers transported in soil, agricultural equipment, and water.

The biology of Cypress round This explains its tenacity as a weed: it is a perennial herbaceous plant with triangular stems, leaves arranged in three rows, and an umbel-shaped inflorescence with purplish spikelets. Its reproduction is predominantly vegetative, through thin rhizomes and tubers in chains (up to 6 or more per rhizome), which store energy reserves and allow regeneration even after stress. As a C4 plant, it exhibits high photosynthetic efficiency under conditions of high temperature and light, with tubers viable for years in the soil (densities exceeding 50/m³ in severe infestations).

Its aggressiveness as a weed stems from intense competition for water, nutrients, and light, coupled with allelopathic effects that inhibit germination and growth of adjacent crops, resulting in productivity losses of 20 to 90% in various cultivated species, such as sugarcane, vegetables, and grains. Furthermore, it serves as an alternative host for insect pests and pathogens, exacerbating the economic and phytosanitary impact on agricultural systems.

Ecologically, Cypress round It adapts to varied soils (preferably moist and fertile, but tolerates moderate drought), warm climates, and open or cultivated areas, being less tolerant of shade, salinity, or low temperatures. Its current pantropical distribution is due to anthropogenic dispersal, with tubers surviving at depths of up to 40 cm and sprouting cyclically, which favors infestations in soils disturbed by tillage or irrigation.

The control of Cypress round This requires an integrated approach, as isolated methods are ineffective due to the underground reserve of tubers. Cultural practices include crop rotation, intercropping with competitive cover crops (such as Sesbania), soil solarization, and irrigation management to reduce sprouting. Mechanical methods, such as repeated cultivation in summer to expose and desiccate tubers, combined with translocated herbicides (e.g., halosulfuron-methyl, sulfentrazone, imazapic, or glyphosate in multiple applications), offer suppression but require integration with mulching (natural or plastic) and density monitoring to prevent re-infestation. In no-till or organic systems, the emphasis is on limited preventive and biological practices, focusing on depleting tuber reserves over cycles. The persistence of Cypress round As a weed, this reinforces the need for sustainable strategies based on ecology and integrated management to minimize losses and preserve agricultural productivity.

Other scientific information:

Cyperus rotundus, a globally distributed and highly competitive weed, has evolved herbicide resistance, posing a significant challenge to sustainable agriculture; however, a lack of genomic resources has limited comprehensive investigations into its resistance mechanisms. Here, we report a chromosome-level genome assembly of triploid Cyperus rotundus (875,13 Mb distributed across 165 chromosomes) exhibiting high synteny among haplotypes. Comparative analysis of six populations revealed that only one population from Changde, Hunan, China (designated R-HN) exhibited dual resistance to both glyphosate and glufosinate. In this population, high expression of the resistance gene at the glutamine synthetase 2 (GS2) target site contributes to glufosinate resistance, while glyphosate resistance is predominantly mediated by non-target site resistance (NTSR) mechanisms. By integrating transcriptomic profiling with yeast-based functional validation, we identified two NTSR genes, CrABCG15 and CrCASPL2C2, that confer glyphosate resistance. Collectively, this study provides a high-quality genomic resource for Cyperus rotundus and advances our understanding of its genomic evolution and herbicide resistance mechanisms. - DOI: 10.1016/j.xplc.2025.101624 -