Striga is a parasitic weed causing remarkable yield lose in Sorghum bicolor. In this study, phytotoxicity of leaf and flower extracts of Striga hermonthica were investigated on three sorghum varieties under laboratory conditions. Before allelopathic bioassay, total phenolics, alkaloids and terpenoids were quantified in the extracts. For allelopathic bioassay, 5 and 10% (w/v) aqueous extracts were prepared by reconstituting dried crude extracts of leaf and flower of S. hermonthica in distilled water. Varieties of sorghum named Muyra 1 (M1), Muyra 2 (M2) and Fendishe (Fe) were treated with equal amounts of 5 and 10% (w/v) extracts in Petri dishes lined with Whatman no.1 filter paper. The control treatment received distilled water and treatments were laid out in a completely randomized design with three replications. Germination parameters were monitored for 15 days and General linear model was used to analyze data. Results showed that both leaf and flower of S. hermonthica produce phenolics, alkaloids and terpenoids. Values of total phenolics and total alkaloids did not show significant variation, whereas total terpenoid was significantly higher in flower than leaf. Percent germination, shoot and root lengths as well as their dry weights were significantly affected by extract concentration, sorghum variety and their interactions. Compared to control, percent germination and seedling growth were highly reduced at 5% w/v extract concentration and completely inhibited at 10% w/v extract concentration. Varieties were not differentially affected by leaf extracts, but M1 and M2 appeared to be more affected than Fe by flower extract. The result also showed that root growth was more affected by extracts than shoot growth. Overall, this study for the first time revealed that S. hermonthica reduces yield of S. bicolor not only due to parasitism, but also through its negative allelopathic effect on seed germination and early seedling growth.

Understanding the fire-prone arid-zone pine species and maquis vegetation's response to fire is very important to reveal the ecology and evolution of these species. During the succession of vegetation, there are complex relationships between allelopathic metabolites and fires. Many plant communities such as pines, maquis, savannas and woodlands are known to play a critical role in the development of succession. However, studies revealing the relationship between succession processes and allelopathic mechanisms in fire-prone ecosystems are quite limited. Most evergreen maquis vegetations are one of the most studied fire ecosystems. In maquis vegetation, fire causes the formation of plant communities that continue with allelochemicals produced by plants, as well as shaping the climate of the region. The event of a living species inhibiting another species by secreting toxic compounds is expressed as allelopathy. These toxic compounds are generally referred to as allelochemicals. Many maquis species that grow in fire-prone ecosystems excrete their allelochemicals, preventing the development of herbaceous species around them and invade their habitats. These chemicals, which accumulate in the soil during the dry season, affect the succession processes in vegetation in the event of a fire and determine which species will follow each other. Considering these relationships, it can be said that allelopathic plants have the potential to change plant diversity in vegetation by changing their functional plant characteristics. The purpose of this review is to determine the relationship between allelochemicals and fire of plant species in fire-prone ecosystems, and to reveal how this affects the succession processes.

Many allelopathic crops are cultivated in agricultural fields, and these plants can influence the growth of other plants in the cultivation environment with their phytotoxic compounds. One of these plants is the faba bean. In this study conducted under the ecological conditions of Sakarya/Arifiye, the allelopathic effects of Eresen-87, Salkim, Bilecik, and Sakarya faba bean genotypes on weeds such as Johnson grass (Sorghum halepense L.), curly dock (Rumex crispus L.), purslane (Portulaca oleracea L.), and wild mustard (Sinapis arvensis L.) were investigated. Weed seeds used in the experiment were collected from agricultural fields in the Sakarya province. Extracts from dried plant parts of faba bean genotypes were prepared and applied to petri dishes containing weed seeds at concentrations of 5% and 10%, with four replications. At the end of the research, it was observed that all faba bean genotypes at all application doses caused a decrease in germination rate (%), root length (cm), and shoot length (cm) parameters in the four weed species tested. The best results were determined as Eresen-87 and Bilecik at 10% concentration. When the activities of fresh and dry extracts of faba bean genotypes was compared, it was determined that dry application had a higher allelopathic effect.