159 Floral-biological Characteristics and Fruit Development of Fennel G. SzØkely, J. BernÆth and . NØmeth Department of Medicinal and Aromatic Plants Szent IstvÆn University, Faculty of Horticultural Sciences H-1502, P.O. Box 53 Budapest, Hungary Keywords: anethole, essential oil, fenchone, floral-biology, Foeniculum vulgare Abstract On the basis of examinations the speed of flower development of two population of fennel (Foeniculum vulgare var. subsp. capillaceum var. vulgare ’Soroksári’ and selected population of genebank origin ’F86’) depends on species and regulated by range of umbels, mainly. The 6 th and 7 th phases of flowering, which are the most time consuming periods, need 7 or 8 days in case of the 1 st range umbels, while only 5 or 6 days in 3 rd range umbels. It was justified as well, that the germination power of seeds depends on maturity stage in which they were collected. Green seeds can be characterised by 40-60 % of germination, while this value increases up over 70 % if waxy and ripen seeds are tested. In harmony with literature data the essential oil content of fruits is the highest in „green seed” stage (5.83 ml/100g and 5.68 ml/100g in case of ’F86’ and c.v. ’Soroksári’, respectively). INTRODUCTION Nowadays, the demand for drugs of fennel (Foeniculum vulgare Mill.) of adequate quality is increasing. The optimisation of production is one of the preconditions to produce economical and stable crop. The widening the knowledge on floral-biology, including conditions of fertilisation seems to be an effective tool for improving the genetic background of the production. In this respect cultivar of Foeniculum vulgare subsp. capillaceum var. vulgare SoroksÆri and a selected population of genebank origin F86 were analysed on individual level. MATERIALS AND METHODS Plant Material In the course of growing season of 2000 flowering dynamics of the c.v. SoroksÆri and F86 populations were examined in 2-3 days intervals analysing the process of flowering paying attention to both internal and external parts of the main, 1 st , 2 nd , 3 rd and 4 th range umbels. There were 8 development phases of flowering distinguished by us in order to characterize the flowering processes, properly. The stadiums, which were distinguished are as follows: 1. Green bud stadium, 2. Yellow bud stadium, 3. Petal opening, 4. Stamina opening, first pollens appear, 5. Pollen mass-production, 6. Stigma appearance, 7. Stigma elongation and ripening, 8. Flowering ceases, small green fruits form. In order to characterise the fruit development processes fruits from 1 st range umbels were taken and analysed, continuously. The sampling was conducted from the start of the fruit development (from the end of fertilisation) until the full ripening, in three different stage of ripening: green seed stage, waxy seed stage and mature seed stage. Proc. Int. Conf. on MAP Eds. J. BernÆth et al. Acta Hort. 576, ISHS 2002