Journal of Plant Diseases and Protection, 113 (4), S. 188–189, 2006, ISSN 1861-3829. © Eugen Ulmer KG, Stuttgart J.Plant Dis.Protect. 4/2006 Evaluation of Solanum rootstock accessions for control of root-knot nematodes and tobamoviruses Bewertung von Solanum-Veredelungsunterlagen hinsichtlich ihrer Resistenz gegenüber Wurzelgallennematoden und Tobamoviren E.A. Tzortzakakis 1* , F.A. Bletsos 2 & A.D. Avgelis 3 1 N.AG.RE.F, Plant Protection Institute, Nematology Lab, PO BOX 2228, GR-71003, Heraklion, Crete, Greece 2 N.AG.RE.F, Agricultural Research Center of Macedonia and Thrace, Department of Vegetables, PO BOX 60458, GR-57001, Thermi-Thessaloniki, Greece 3 N.AG.RE.F, Plant Virus Lab, GR-71003, Heraklion, Crete, Greece * Corresponding author, e-mail etzortza@her.forthnet.gr Received 16 March 2006; accepted 13 April 2006 Summary Twenty-two Solanum accessions used as rootstocks were evaluated for their resistance towards the root-knot nema- todes Meloidogyne javanica and M. incognita and three tobam- oviruses (TMV, ToMV and PMMV). Five out of seven S. gilo accessions, namely RNL 300/328, RNL 304/337, RNL 308/347, RNL 297/323 and RNL 307/346, were resistant or immune against all viruses while others within S. aethiopicum group kumba, S. linnaeanum, S. macrocarpon and S. dasyphyl- lum were susceptible. Furthermore, variability of plants with- in the same accession being either susceptible or resistant/ immune to viruses was recorded in others. Both nematode species produced galls and egg masses on all tested plants. Key words: Meloidogyne javanica, Meloidogyne incognita, pepper mild mottle virus (PMMV), tobacco mosaic virus (TMV), tomato mosaic virus (ToMV) Zusammenfassung Zweiundzwanzig Veredelungsunterlagen der Gattung Sola- num wurden hinsichtlich ihrer Resistenz gegenüber drei Toba- moviren (TMV, ToMV and PMMV) und den Wurzelgallenne- matoden Meloidogyne javanica und M. incognita bewertet. Die fünf (von sieben untersuchten) S.-gilo-Unterlagen RNL 300/ 328, RNL 304/337, RNL 308/347, RNL 297/323 und RNL 307/ 346 erwiesen sich als resistent oder immun gegenüber allen Viren, während andere Unterlagen der Arten S. linnaeanum, S. macrocarpon, S. dasyphyllum und der S.-aethiopicum-Gruppe kumba anfällig waren. Andere Unterlagen derselben Akzession variierten darüber hinaus in ihrer Anfälligkeit oder Resistenz/ Immunität gegenüber diesen Viren. Beide Nematodenarten bildeten Gallen und Eimassen an allen überprüften Pflanzen. Stichwörter: Meloidogyne javanica, Meloidogyne incognita, Mildes Paprikascheckungsvirus (PMMV), Tabakmosaikvirus (TMV), Tomatenmosaikvirus (ToMV) Grafting vegetables on resistant rootstocks is an effective method to control soil-borne pathogens in areas where they are intensively grown. Experiments with grafted eggplants showed promising results for control of fungal pathogens (IOANNOU 2001; BLETSOS et al. 2003; BLETSOS 2006) and root-knot nematodes (IOANNOU 2001) under greenhouse conditions in Greece and Cyprus. According to our knowledge, information on the response of Solanum rootstocks is limited for root-knot nematodes and absent for tobamoviruses. Several common cultivated hybrids of tomato and eggplant in Crete are resistant to tobamoviruses but not to root-knot nematodes. For successful grafting and economic plant production, the rootstocks should be resistant to both root-knot nematodes and tobamoviruses. The latter is important, as an infection by soil-borne viruses will cause a hypersensitive reaction in the rootstock with detrimental effects on the grafted virus–resistant plant. Therefore, Solanum accessions (regenerated by F. A. Bletsos, E. U. EGGNET Project) were evaluated against tobacco mosaic virus (TMV), tomato mosaic virus (ToMV) and pepper mild mottle virus (PMMV). Furthermore, the ability for reproduction of one Cretan popula- tion each of M. javanica and M. incognita was tested. The aim of the work described here is to assess the potential use of these Solanum accessions as rootstocks for grafting tomato and eggplant, as the above mentioned viruses and root-knot nema- todes are widespread in Crete causing severe economic losses. Nematode resistance was evaluated as follows. Egg masses of each nematode species were picked from roots of galled tomatoes, placed on 90 Pm mesh sieves sited over water in shallow trays and incubated at 25°C (HUSSEY and BARKER 1973). Hatched second-stage juveniles (J 2 ) collected within four days were used as inoculum and pipetted in 300 ml pots with seedlings at the 2-4 true leaf stage at a rate of c. 300 J 2 per plant. The plants were grown for 6 weeks in a climate room with 16 h photoperiod and 24-26°C soil temperature. Plants were watered and fertlized as required. The number of galls and egg masses was assessed in 4-5 replicates under a stereoscope. In each experiment 3-4 accessions were tested together, with controls being either the susceptible tomato cv. ‘Ace’ or the eggplant cv. ‘Tsakoniki’. Means were compared with their respective controls by t-test at P d 0.05 and results were presented as percentage of galls and egg masses on each Solanum accession compared with the control. For virus transmission, 10-15 seedlings from each accession at the third leaf stage were mechanically inoculated at the cotyledons and the first true leaf with a purified virus suspen- sion (0.1 mg/ml virus nucleoprotein). After one month the presence of virus symptoms was detected macroscopically and confirmed with both serological (DAS-ELISA) and biolog- ical tests. For biological detection, mechanical inoculation was done on test plants which were Nicotiana glutinosa for TMV and ToMV and N. rustica for PMMV. The S. melongena cv. ‘Tsakoniki’ served as control for TMV and ToMV while Capsi- cum annuum cv. ‘Lamuyo’ for PMMV. Both nematode species formed galls in all tested plants. The number of galls on tomato and eggplant ranged from 18-45 per root for M. javanica and 17-53 for M. incognita. The respective number of egg masses ranged from 9-30 for M. javanica and 10-38 for M. incognita. In some Solanum accessions the number of galls and egg masses were signifi- cantly lower than in the controls while for others they were similar or significantly higher (Table 1). Short Communication