Caracterização do crescimento de plantas de três biotipos de cravorana (Ambrosia artemisifolia L.) da região sudoeste do Paraná

Abstract

Lately, there have been important reports from farmers in the Southwest region of Paraná about the high degree of difficulty in controlling Cravorana (Ambrosia artemisifolia) in crops, with evidence of resistance to various herbicides, with different mechanisms of action. The present study aims to characterize the vegetative and reproductive growth of plants of three biotypes (Realeza, Reserva do Iguaçu and Mangueirinha) of A. artemisifolia throughout its cycle.. The experiment was conducted in pots containing soil, in a greenhouse at the UTFPR Agronomy Course, Pato Branco Campus. A completely randomized experimental design was used with 4 replications in a 3 x 8 bifactorial scheme, in which the first factor was composed of 3 biotypes of Ambrosia atermisifoliacravorana and the second factor consisted of 8 periods of plant growth evaluation (15, 30 , 45, 60, 75, 90, 105, 120 days after transplantation). Dry matter accumulation in plants adjusted to a sigmoidal model in the three biotypes evaluated, demonstrating slow growth up to 60 days after transplantation (DAT), more accelerated between 60 and 90 DAT, declining thereafter. The dry matter allocation pattern differed between the three biotypes. Although all biotypes allocated a large proportion of dry matter to leaves up to 60 DAT, there was a reversal of allocation to other parts of the plant after flowering (75 DAT). From flowering onwards, the Reserva do Iguaçu biotype allocated more dry matter to the stem and less to the inflorescence than the Realeza and Mangueirinha biotypes.