Correlation between macronutrient content and sunflower resistance to Sclerotinia sclerotiorum measured by sclerotia infection of stem

Abstract

Nutrition of plants has a substantial impact on the predisposition of plants to be attacked or affected by pests and diseases. Since availability and nutrient quantity in the host plants is a limiting factor for Sclerotinia sclerotiorum infection development in sunflower, the aim of this work was to determine macronutrient content in photosynthetic tissue (leaves) of sunflower plants before and after development of fungus infection, and to find the correlation between macronutrient content and resistance to sclerotium infection. The study was carried out on eight sunflower inbred lines. Macronutrient (N, P, K, Ca and Mg) content was determined in dry plant material of control and sclerotium infected plants. There was a high positive correlation between N content in infected plants and resistance, which points to the important role of this nutrient in sunflower defence from Sclerotinia attack. Moderate negative correlation between K and Ca content in control plants showed that the content of these nutrients in healthy plants could be used as an indicator of cultivated sunflower resistance/susceptibility to Sclerotinia infection.