The Asiatic hybrid lily ( Lilium L.) 'Connecticut King' harbours several beneficial traits such as partial resistance to Fusarium and complete resistance to tulip breaking virus (TBV). The variation in resistance to Fusarium was determined in four different greenhouse tests in four different years on the same 100 descendants of a backcross population. There was considerable variation in Fusarium resistance levels over the years. TBV resistance was determined and segregated, as expected, like a monogenic trait (1:1). In order to identify quantitative trait loci (QTLs) for Fusarium resistance and also to identify linked markers to the TBV resistance a QTL mapping approach was carried out in this backcross population. Segregation of 399 polymorphic AFLP TM (amplified fragment length polymorphism) fragments was determined. Two different enzyme combinations were used, PstI/MseI and EcoRI/MseI, in the latter one extra selective nucleotide was added to the MseI primer. A paternal ('Connecticut King') linkage map was calculated. This map consisted of 24 linkage groups ( Lilium 2n=2x=24) with 251 markers covering 1367 cM. About 25% of the markers remained unlinked. Four QTLs for Fusarium resistance mapped to linkage groups 1, 5, 13 and 16 respectively. The resistance gene for TBV was placed on linkage group 9.

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Interspecific crosses were made between seven Lilium species, viz. L. candidum, L. concolor, L. dauricum, L. henryi, L. longiflorum, L. nepalense and L. rubellurn. A complete diallel cross was carried out between these seven species, including selfand intraspecific pollinations using three pollination methods: normal pollination on the stigma, pollination on the ovary after cutting the style, and pollination on the stigma with the aid of' mentor' (non-functional, compatible) pollen. Embryo rescue, starting 35 days after pollination, was applied to all interspecific combinations. The percentage of successful crosses was about 2.8% after normal pollination, 5.4% after cut-style pollination and 3.8% with the mentor pollen technique. Crosses with L. nepalense were exceptional in that embryos died during the embryo culture phase. Seventeen cross combinations (including 4 reciprocals) yielded 62 embryo plantlets from 839 interspecific pollinations.

Fusarium oxysporum f.sp. gladioli is a major pathogen of Gladiolus and resistance to this fungus is needed. A standardized screening assay to assess resistance levels in breeding selections must be developed. Corms of cultivars. ranging from susceptible to resistant, were planted either in soil infested with various inoculum levels or incubated in vitro after wound inoculation. The soilgrown corms were rated using relative length of the shoots and average disease rating. In vitro incubated corms were evaluated visually after 6 weeks. All parameters produced similar results. It was concluded that the relative length of shoots of corms after 8 weeks of growing in soil with a high inoculum level combined with the assessment of the average disease rating of the corms after either 8 or 20 weeks is an effective screening assay. Zusammenfassung fusaruim-Resistenz bei Gladiolus: Entwicklung eines Screening-TestsFusarium oxysporum f. sp. gladioli ist ein wichtiges Pathogen von Gladiolus, und zur Eindammung dieser Krankheit ist die Zlichtung resistenter Gladiolen erforderlich. Hierzu muB ein standardisierter Screening-Test entwickelt werden, der die Erfassung verschiedener Resistetizgrade ermoglicht. Knollen anfalliger und resistenter Sorten wurden in Boden gepflanzt, die verschiedene Inokulummengen enthielten, oder nach einer Wundinokuiation in vitro inkubiert. Die Resistenz der im Boden gehaltenen Knollen wurde anhand der relativen Lange der Triebe und des durchschnittlichen AusmaBes der Erkrankung erfaBt. Die in vitro inkubierten Knolien wurden nach sechs Wochen visuel! bonitiert. Aile Parameter fuhrten zu vergleichbaren Ergebnissen. Es wurde gefolgert, daC die Erfassung der relativen Lange der von den Knollen gebildeten Triebe nach achtwochigem Wachstum in einem Boden hohen Inokulumgehalts in Verbindung mit der Bonitur des durchschnitthchen Ausmafles der Erkrankung der Knollen nach acht oder 20 Wochen einen effektiven Screening-Test darstellt.

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