The Importance Of Worldwide Tomato

Worldwide Tomato (Solanum lycopersicum L.) is the second most cultivated vegetable crop after potato, and has an important role in global trade due to production volume and value (FAO, 2013). Worldwide, more than hundred diseases caused by biotic and abiotic agents had been reported, contributing to a significant decrease in its productivity (Jones et al., 1991). Early blight caused by the fungal genera Alternaria, is perhaps the most common and important foliar disease of tomato in the world, leading to a reduction of economic fruit yield as well as quality. (Khan et al. 2002). Typical disease symptoms are characteristic dark necrotic lesions with concentric rings on leaves (Van der Waals et al. 2003). Disease develops in areas of high humidity

But Simmons (2000) first time described several other species to be associated with the disease based on his morphology-based taxonomic revision of Alternaria specimens from Solanaceous crops. The other species associated with the disease are A. grandis, which was the dominant species from potato, and a similar fungus A. tomatophila which is more common on tomato. This morphological taxonomic revision was later supported by inoculation studies (Fraser and Zitter 2003). The molecular analysis of the above associated species also confirmed the same results (Gannibal et al. 2014). Andersen et al. (2008) did the metabolite profiling and the supported the morphological taxonomic revision. Recently specimens belonging to this species were moved to a new species named A. linariae together with other isolates from Solanaceae, Cucurbitaceae and Scrophulariaceae (Woudenberg et al. 2014). In our study also we found A. alternate and A. tenuissima to the causal agent of early blight of tomato from the samples collected from North Indian region. Out of total 11 isolate studied representing 11 groups of 90 isolates, none of them found to be A. solani and 10 isolates were confirmed as A. alternate and one as A.