Differences in resistance in onion [Allium cepa] cultivars to pink root rot disease in Iran

• Published in: Journal of general plant pathology : JGPP Vol. 74; no. 1; pp. 46 - 52
• Main Authors: Esfahani, M.N.(Plant Pests and Diseases Research Inst., Tehran (Iran)), Pour, B.A
• Format: Journal Article
• Language: English
• Published: Japan Japan : Springer Japan 01.02.2008; Springer Japan
• Subjects: Agriculture; ALLIUM CEPA; Biomedical and Life Sciences; DISEASE RESISTANCE; ENFERMEDADES FUNGOSAS; ENSAYOS DE VARIEDADES; ESSAI DE VARIETE; FUNGAL DISEASES; IRAN ISLAMIC REPUBLIC; IRAN REPUBLICA ISLAMICA; IRAN REPUBLIQUE ISLAMIQUE; Life Sciences; MALADIE FONGIQUE; Microbiology; PATHOGENICITY; PATOGENICIDAD; PHOMA; Plant Pathology; PODREDUMBRE DE LA RAIZ; POURRITURE DES RACINES; POUVOIR PATHOGENE; PYRENOCHAETA; RESISTANCE AUX MALADIES; RESISTENCIA A LA ENFERMEDAD; ROOT ROTS; VARIETY TRIALS; Resistance
• ISSN: 1345-2630; 1610-739X
• DOI: 10.1007/s10327-007-0070-4

Forty-five onion (Allium cepa) cultivars were evaluated for disease resistance to the fungal pathogen Pyrenochaeta terrestris (pink root disease). Forty-three Iranian cultivars and two commercially exotic resistant cultivars (Texas Early Grano and Yellow Sweet Spanish) were grown in a glasshouse for two successive years (2003 and 2004) in Isfahan, Iran. Susceptibility of the cultivars was determined using a scale of 0-3. Six cultivars had significantly lower susceptibility of pink root compared to the exotic ones. High susceptibility tended to be associated with high mean scores (2-3), and the highly resistant cultivars had the lowest scores (0-1). In addition, the 45 examined cultivars were ranked from 1 to 45 according to their markedly differing reactions to P. terrestris, which differed markedly. Of 32 cultivars that were less resistant, 30 with an intermediate status or tolerance (1-2) differed considerably in their rank order. No pink root symptoms were seen in the early stages, but on blotter paper or wheat-straw agar some roots turned pink with no pycnidia formation, whereas on potato dextrose agar medium (PDA) with a few fresh healthy and sterile onion roots on the surface, mycelia and pycnidia were recovered. Variance and cluster analysis showed similar results among the cultivars with various levels of resistance, tolerance and susceptibility as determined by scoring scales.