Genotype‐isolate interaction for resistance to black stem in sunflower (Helianthus annuus)

• Published in: Plant pathology Vol. 56; no. 4; pp. 654 - 660
• Main Authors: Darvishzadeh, R., Dechamp‐Guillaume, G., Hewezi, T., Sarrafi, A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.08.2007; Blackwell; Wiley
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; black stem; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Genetics and breeding of economic plants; genotype‐isolate interaction; Helianthus; Helianthus annuus; Leptosphaeria lindquistii; Life Sciences; partial resistance; Pest resistance; Phoma; Phoma macdonaldii; Phytopathology and phytopharmacy; Phytopathology. Animal pests. Plant and forest protection; Plant pathogens; sunflower; Varietal selection. Specialized plant breeding, plant breeding aims; Vegetal Biology; Plant pathology; genotype-isolate interaction; Plant pathogen; Mycosis; Phoma macdonaldii; Compositae; Stem; Fungi; Dicotyledones; Angiospermae; Fungi Imperfecti; C3-Type; Interaction; Genotype; Host agent relation; black stem; Fungus resistance; sunflower; Infection; Helianthus annuus; Sensitivity resistance; partial resistance; Vegetative apparatus; Isolate; Spermatophyta; Nonspecific resistance; Oil plant (vegetal); Partial resistance; Black stem
• ISSN: 0032-0862; 1365-3059
• DOI: 10.1111/j.1365-3059.2007.01603.x

Two experiments were undertaken to determine the partial resistance of sunflower genotypes to seven isolates of Phoma macdonaldii. In the first experiment, 28 genotypes, including recombinant inbred lines and their parents, M6 mutant lines developed by gamma irradiation, and some genotypes from different geographical origins, were used. The experiment consisted of a split‐plot design with three replications, each with 12 seedlings per genotype per isolate, in controlled conditions. Seven days after inoculation, plantlets were scored on a 1–9 scale for percentage necrotic area. Highly significant differences were observed among genotypes, isolates and their interactions. The presence of a differential interaction between genotypes and P. macdonaldii isolates was confirmed in a second experiment using 12 genotypes representing large variability for partial resistance to P. macdonaldii isolates, as identified in the first experiment. Inbred lines B454/03, ENSAT‐B5 and LC1064C were the most susceptible sunflower genotypes, whereas two American lines SDR19 and SDR18 presented high partial resistance to all P. macdonaldii isolates studied. The least and most aggressive isolates were MA6 and MP3, respectively. Isolates interacted differentially with sunflower genotypes. This study identified two genotypes (AS613 and PAC2) presenting specific resistance to isolate MP8. The results also showed a wide range of isolate‐nonspecific partial resistances among the lines tested. The information presented here could assist sunflower breeders to choose parents of crosses for breeding of durable resistance to phoma black stem disease.