The reaction of flue-cured tobacco genotypes to root- knot nematode (Meloidogyne incognita)

Root knot causing by nematodes is a major disease of tobacco in all tobacco-producing countries in subtropical and tropical zones. Resistant cultivars implementation is the preferable economic management method. Nematicides are expensive and may pollute the environment. Therefore, this study evaluated reaction of 100 flue-cured tobacco genotypes to Meloidogyne incognita based on completely randomized design with three replications in greenhouse at 25 ± 3oC of Tirtash Research and Education Center in 2010-2011 years. Each tobacco seedling was inoculated with 2000 eggs and second stage juveniles in 1.5 kg pot soil. After 60-70 days they have evaluated according to gall index, reproduction factors, number of egg masses and average of eggs per egg mass. Results of variance analysis showed that there were significant differences among cultivars. Genotypes of Coker 176, Mac Nair 944, S 392-3 S, TL33 and Bel 61-10 had the lowest gall index and reproduction factors. Eighteen susceptible and resistance genotypes were selected based on results of 2010 year and based on completely randomized design with five replications. The experiment was conducted in Tirtash Research and Education Center in 2011 year. Results of variance analysis showed that there were significant differences among the cultivars. Genotypes of Bel 61-10 with the lowest of gall index, reproduction factors, number of egg masses and average of eggs per egg mass, respectively 2, 1.1, 38.2 and 357 and Coker 176 by 1.6, 1.18, 38 and 354 as resistant genotypes were introduced. Genotype of Bel 61-10 as resistant parents in breeding work will be used in the future. Cultivar of Coker 176 for cultivation in the affected tobacco growing areas to root knot nematode is recommending.