Allelopathic effect of sunflower broomrape (Orobanche cumana Wallr.) on the development of sunflower (Helianthus annuus L.)

Valentina Encheva, Plamen Marinov-Serafimov, Irena Golubinova, Shteliyana Kalinova

Abstract: The allelopathic effect of dry biomass of sunflower broomrape (Orobanche cumana Wallr.) collected from ten regions of the Republic of Bulgaria was studied under laboratory conditions at the Institute for Forage Crops – Pleven. The allopathic effect of the experimental samples of sunflower broomrape on the seed germination and on the initial development of the sunflower, variety “Paredovik” was followed. It was found that the studied concentrations (8.0, 16.0 and 32.0% w/v) dry weed biomass of sunflower broomrape showed a stimulatory effect (from -0.7 to -55.3%) or an inhibitory effect on the germination of seeds (from 1.8 to 43.1%) and on the initial development (from 2.4 to 21.0%) of sunflower, variety “Paredovik”. Depending on the alleopathic effect and the origin of the sunflower broomrape, they can be grouped in the following order: P7(Selanovtsi)(86.9%) → P9(Radnevo)(83.0%) → P4(Kardam) (73.4%) →P5(Tyulenovo) (70.7%) →P6 (Dyakovo) (61.9%) →P1 (Kardam) (54.8%) →P2(DAI – Infectionfirld) (50.6%) →P3(DAI – Experimental field) (50.2%) →P8(Svishtov) (46.0%) → P10 Sozopol broomrape on Artemisia maritima L.) (27.9%). The highest overall allelopathic potential (OAP = 0.6) conditionally was determined for sunflower broomrape originating P2(DAI – Infection field and P3 (DAI – Experimental field). The lowest overall allelopathic potential (from 0.2 to 0.3) was determined for sunflower broomrape with the origin P7 (Selanovtsi) and P9 (Radnevo). This information can be explained by the genetic differences of the studied origins.

Keywords: allelopathic effect; broomrape; inhibition; sunflower

Date published: 2020-02-26