Effects of nicosulfuron on biological production of weedy sunflower (Helianthus annuus)

Abstract

Field experiments were conducted to quantify the effects of nicosulfuron on biological production of weedy sunflower (Helianthus annuus). Plants of this weed species were sown in plots sized 5x4.2 m with inter-row spacing of 24 cm, and 70 cm distance between rows. Plants with two pairs of developed leaves were treated with nicosulfuron using the next rates: 0, 10, 20, 40, 60 and 80 g a.i. ha-1. Vegetative parameters (plant height, fresh weight and leaf area) were recorded five times during vegetation, including the first measurement just before herbicide application and four measurements at intervals of about two weeks. Head and seed production (number of heads per plant, head weight, head diameter, weight of seeds per head, weight of seeds per plant, number of seeds per plant) were determined after seed maturity. The application of nicosulfuron caused growth reduction of weedy sunflower in comparison with the control. All application rates of this herbicide reduced vegetative (height, fresh weight, leaf area) and some generative (number of heads per plant, weight of seeds per plant, number of seeds per plant) parameters, which decreased with increasing rates of nicosulfuron. Effects on the remaining generative test parameters (head weight, head diameter, weight of seeds per head) were not analogous to the effects on other parameters.

Efekat nikosulfurona na biološku produkciju hibridne forme korovskog suncokreta (Helianthus annuus) ispitivan je u poljskim ogledima. Biljke ove korovske vrste su posejane na parcelicama veličine 5x4,2 m, sa rastojanjem biljaka u redu od 24 cm i razmakom između redova od 70 cm. Biljke u fazi dva para razvijenih listova su tretirane nikosulfuronom, koji je primenjen u sledećim količinama: 0, 10, 20, 40, 60 i 80 g a.s. ha-1. Vegetativni parametri (visina biljaka, sveža masa i površina listova) su mereni pet puta tokom vegetacije, što uključuje prvo merenje neposredno pre primene herbicida i četiri merenja u intervalima od oko dve nedelje. Produkcija glavica i semena (broj glavica po biljci, masa glavice, prečnik glavice, masa semena po glavici, masa semena po biljci, broj semena po biljci) je određena nakon sazrevanja semena. Primena nikosulfurona je prouzrokovala redukciju rasta hibridne forme korovskog suncokreta u poređenju sa kontrolom. Sve količine ovog herbicida su redukovale vegetativne (visina biljaka, sveža masa i površina listova) i neke generativne (broj glavica po biljci, masa semena po biljci, broj semena po biljci) parametre, koji su se smanjivali sa povećanjem količine nikosulfurona. Efekat na ostale generativne parametre (masa glavice, prečnik glavice, masa semena po glavici) nije bio uporediv sa efektom na ostale parametre.