Document Type : Plant Pathology
Authors
Abstract
Root knot nematodes (Meloidogyne spp.) are one of the important parasitic nematodes of tobacco in almost all tobacco-growing areas. Determination of damage of Meloidogyne incognita (Kofoid and White, 1919) Chitwood, 1949(race-2) on some of tobacco commercial cultivars, this study was carried out in factorial with two factors including: six inoculums levels namely 0, 1, 3, 5, 7, 9 eggs and second stage juveniles(J2) per gram of pot soil under artificial inoculations and some of tobacco commercial cultivars (Coker 347, Burely 21, K326) based on completely randomized design (CRD) with 18 treatments and four replication in Tirtash Research and Education Centre in 2009 year. After 4 times harvesting, nematodes were extracted from soil and root. The number of nematodes were counted in roots and soil. Gall index, reproduction factors (Rf), the growth factors, fresh and dry weight of leaves, height of plant, fresh and dry weight of roots, income and average Price per kilogram were measured. The givendata were analyzed with MSTAT-C program. The results showed that, there was a progressive decrease in plant growth as the inoculums levels of the nematode increased nine nematodes per gram soil, reduction maximum in growth parameters of all tested tobacco cultivars. Damage of root knot nematode (Meloidogyne incognita) on some of tobacco commercial cultivars was Determined 3 eggs and second stage juveniles (J2) per gram of pot soil. The maximum nematode reproduction factors (Rf) was 69/83 at an initial population density of 5 eggs and second stage juveniles (J2) per gram of pot soil. Maximum damage of 84%, 80% and 73% were obtained for Coker 347, Burley 21 and K326, respectively.
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