New gentic ressources for Styrian Oil-pumpkin

Introduction of further resistance genes against Zucchini Yellow Mosaic Virus (ZYMV) in Styrian oil pumpkin using classical and molecular selection methods Project No. 1228 Lelley1 T., Pachner1 M., Stift1 G., Winkler2 J., and Pfosser3 M. 1IFA-Tulln, Biotechnologie in der Pflanzenproduktion, Konrad Lorenz Str. 20, 3430 Tulln 2Saatzucht Gleisdorf Ges.m.b.H. Am Tieberhof 33, 8200 Gleisdorf 3Universität Wien, Institut für Botanik, Rennweg 14, 1030 Wien The severe virus epidemic in 1997 has shown, that Austrian oil-pumpkin (Cucurbita pepo L.) varieties have no genetically determined protection against Zucchiny Yellow Mosaic Virus (ZYMV). The rapid development of such varieties became absolutely necessary. As a consequence in 1998, in cooperation between the federal government and the governments of states Styria, Lower Austria and Burgenland, the "Pumpkin Project" was established. In 2001 this project was extended with the project No. 1228, for another two years. Genetically controlled resistance was not yet found in C. pepo , but at least two resistance genes were transferred from C. moschata, another cultivated Cucurbita species, also known as tropical pumpkin, into various zucchini genotypes. In the first three years of the project we transferred a recessive tolerance gene from the zucchini variety ´Tigress´, to oil-pumpkin. This tolerance gene originated from the Nigerian C. moschata landrace ´Nigerian Local´ (NL-resistance). In the last two years we transferred a second, dominantly inherited, resistance gene, from another zucchini genotype. This gene originated from a Portuguese C. moschata landrace ´Menina´ (M-resistance). Through a back-cross program, this second resistance gene was also transferred into two advanced breeding lines of Saatzucht Gleisdorf. The obtained lines have already been handed over to the Saatzucht Gleisdorf. Parallel to the breeding program we started to develop molecular markers linked to the resistance genes. Such markers represent DNA polymorphisms which are easy to identify. They help to select the gene without artificial infection and the number of plants to be handled. While, unfortunately, we found no such marker for the NL-resistance, very good markes could be detected for the M-resistance. This markers are already in use in the selection program of Saatzucht Gleisdorf. Molecular markers make possible to unite different resistance genes in one genotype (Pyramiding). Thereby, the virus has to overcome a higher barrier to disease the plants. We started to join the two genes introduced previously into the breeding material of Gleisdorf. The first infection experiments with selfed F2 progenies will be carried out in this winter. We hope to be able to identify the presence of NL-resistance, for which we did not find a marker, by the specific phenological response of the plants to the virus. Crossings and progeny testings for resistance of different C. moschata genotypes revealed further