Heredity of Resistance to Botrytis cinerea in Sunflower (Helianthus annuus) Measured by Artificial Infections

Abstract

This study was made to determine the reactions of sunflower genotypes to artificial infections of Botrytis cinerea under netting tunnels with irrigation. The genotypes were the parents and F1 hybrids of a factorial cross between 5 female (male sterile) and 5 restorer lines. Their resistance levels were measured by the mean delay between infection and symptom appearance on the capitulum. Significant genotypic differences in reaction to B. cinerea were shown. The ratio of general combining ability to specific combining ability was 2.9, indicating that additive effects are important. However, there were some significant interactions between male and female parents. The mean parent-hybrid and parent-progeny regressions were both significant with correlation coefficients of r = 0.57 and r = 0.66 respectively. It is concluded that breeding programmes with tests for B. cinerea resistance in early generations should be effective in the development of sunflower hybrids with improved B. cinerea resistance.