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Pak. J. Bot., 44(3): 1141-1146, 2012.

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RESISTANCE OF SOLANUM SPECIES TO PHYTOPHTHORA INFESTANS EVALUATED IN THE DETACHED-LEAF AND WHOLE-PLANT ASSAYS

KHALID PERVAIZ AKHTAR^1*, MUHAMMAD YUSSOUF SALEEM¹, MUHAMMAD ASGHAR¹, SHAUKAT ALI², NIGHAT SARWAR¹ AND MUHAMMAD TANVIR ELAHI¹

Abstract: The reaction of 82 tomato genotypes belonging to 8 Solanum and a Lycopersicon species against Phytophthora infestans causing late blight was determined using detached-leaf and whole-plant assays. None of the test genotypes was immune or highly resistant. Of the 82 commercial and wild genotypes only TMS-2 (male-sterile and characterized by indeterminate growth) belonging to Lycopersicon esculentum was resistant with severity index of 2.4 in the detached-leaf assay on 0-5 scale (where 5 was highly susceptible) and percent disease index (%DI) of 23.3% under the whole-plant assay. Among the remaining genotypes, 41 were susceptible and 40 were highly susceptible under the detached-leaf assay, while 18 were susceptible and 63 were highly susceptible under the whole-plant assay. However, there was a significant difference in %DI for genotypes under the whole-plant assay. The response of whole-plants to inoculation with P. infestans in the detached-leaf assay was similar in all cases. The overall screening results indicate that TMS-2 is a good source of resistance and it can be useful for the development of tomato hybrid cultivars resistant to late blight.

¹ Nuclear Institute for Agriculture and Biology (NIAB), PO Box-128, Jhang Road, Faisalabad, Pakistan.

² Plant Pathology Section, Plant Pathology Research Institute, Jhang Road,Faisalabad, Pakistan.

*Corresponding author e-mail: kpervaiz_mbd@yahoo.com