Ecologists find wheat genetically resistant to fungus

Ecologists have identified genotypes that are resistant to a dangerous fungal pathogen that infects plants before the snow melts and reduces yields. The results are published in Plants.

Pathogenic fungus Microdochium nivale infects crops, causing the so-called snow mold. After the snow melts, spots with a web-like mold of the fungus appear on the leaves of winter crops. Gradually the leaves die off, and if the lesion is too great then the whole plant dies, along with the root. In order to prevent the death of crops and at the same time not to use chemical treatment  it is necessary to develop varieties resistant to the fungus. Ecologists have discovered several such varieties of wheat. The study was conducted by scientists from the All-Russian Research Institute of Phytopathology, Federal Horticultural Center for Breeding, Agrotechnology and Nursery , North Kazakhstan University, Moscow Timiryazev Agricultural Academy, Vavilov All-Russian Institute of Plant Genetic Resources and RUDN University.

“Rot of winter crops is observed in plants that spend a long time at a temperature of about 0 ° C in relatively warm soil, without sunlight and under thick snow cover. Under such conditions, plants quickly “burn” nutrients. This weakens their resistance, and they become an easy target for a fungal infection, most often snow mold. Selection allows you to increase productivity and resistance to stress factors. Selection of varieties with resistance to pathogens is the most reliable and cost-effective method of disease control”, said Rebouh Nazih, PhD, Associate Professor of the Department of Environmental Management of RUDN.

Ecologists have discovered wheat varieties resistant to snow mold in the collection of plant genetic resources of the Vavilov All-Russian Institute of Plant Genetic Resources. This collection contains up to 1085 samples of crops from each year’s crops. The researchers took data for 15 years and found infected samples in ten of them (the earliest sample is 1978, the latest is 2021). 12 genotypes in the collection were resistant to snow mold. Knowing these genotypes, it is possible to carry out the selection of cereals resistant to the pathogen.

Ecologists have also been able to identify factors that contribute to the development of the disease. They analyzed the weather conditions that were in each of the studied years. Among them were abiotic factors – that is, caused by non-living organisms, for example, snow that fell too early. It weakens the immunity of plants, which is why they cannot cope with the pathogen.

“Abiotic stress factors, such as snow covering thawed soil at temperatures 1.0–4.6 °C above normal, were found to be the main cause of the spread. Under such conditions, winter wheat grasses continue to grow, breathe, and consume their nutrient stores, while their immune systems are weakened, making plants susceptible to fungal infections. The combined action of abiotic and biotic stress factors leads to excessive crop loss. As a protective measure, we recommend combining agricultural practices with nitrogen fertilization in the spring. The discovered snow mold resistant genotypes can be recommended to breeders”, said Rebouh Nazih, PhD, Associate Professor of the Department of Environmental Management of RUDN.