INFLORESCENCE AND FLOWER DIFFERENTIATION IN THE GRAPEVINE (V. VINIFERA L.) VARIETIES 'ZILAVKA' AND 'BLATINA'

The different dynamics of flower differentiation i.e. flowering and the functional capacity of reproductive organs in grapevine must be studied as genotypic specificity under particular agroenvironmental conditions and brought to a level at which standardized biological control of fruiting is exercised in order to define sustainable production systems. Research on the functional morphology of the inflorescence and flower in the indigenous grapevine varieties 'Zilavka' and 'Blatina' as the major ones used for grape production in Bosnia and Herzegovina (B&H) was conducted in 2010-2011 through analysis of permanent histological slides. The morphological characteristics of the inflorescence, as observed through the presence and distribution of flowers, and the flowering dynamics of individual flowers in the inflorescence pave the way for the normal course of flowering and pollination in the studied varieties. During inflorescence development, the degree of flower congregation in the distal part of the inflorescence is defined as a varietal characteristic. The inflorescence in 'Zilavka' and 'Blatina' grapevines forms a cone-shaped panicle due to the different structure of side branches i.e. different morphology and structure of branching on the axes of simple botryose inflorescences along the inflorescence axis, when observed from the top down to the base. The sequence and dynamics of differentiation of the flower generative elements clearly indicate protandry in both varieties.