Sunflower genotypes tolerance to charcoal rot (Macrophomina phaseolina (Tassi) Goid.) under the field conditions

Sunflower (Helianthus annuus L.) is one of the most important crops grown in the world, but it can be attacked by more than 30 different pathogens. The areal of Macrophomina phaseolina (Tassi) Goid., one of the sunflower pathogens nowadays often found in temperate regions, has been spreading over the last few years due to climate change. The most effective eco-friendly method for controlling charcoal rot caused by M. phaseolina is growing resistant sunflower cultivars. Due to that, 24 commercially available hybrids and 70 inbred lines were tested for M. phaseolina tolerance in a two-year trial. Under the field conditions, two different inoculation methods were used - the Unwounded Stem Base Inoculation (USBI) and Toothpick (TP) method. This study identified five highly tolerant hybrids and 12 inbred lines that can be used in breeding programs for improvement of future genotypes. Sunflower genotype screening tests for Macrophomina tolerance indicated that both inoculation methods should be applied together to provide reliable results, and that stem lesion length is a reliable trait for disease severity assessments.