FRUITING HABIT AND BRANCHING PATTERN AFFECT VEGETATIVE GROWTH AND REPRODUCTIVE ABILITY IN WALNUT (JUGLANS REGIA L.)

The architectural analysis of 3-year-old fruiting branches was conducted on free grown walnut seedlings of unknown origin to describe the effect of fruiting habit and branching pattern on vegetative and reproductive development in walnut. The trees belong to four morphological types (terminal - I, intermediate with mesotonic branching - II, intermediate with acrotonic branching - III and lateral - IV). The analysis was performed over three years. At the fruiting branch level, the total length of 3-, 2- and 1-year-old wood in morphotype IV was 8% lower than in morphotype I and 33% lower than morphotypes II and III. The ratio between the number of flowering and vegetative 2-year-old shoots 2YS was 0.24 in morphotype I compared to 0.95 in type II, 0.92 in type III and 1.45 in type IV. For the 1-year-old shoots 1YS, this ratio was 0.12 in morphotype I, 1.23 in type II, 1.76 in type III and 2.89 in type IV. At the shoot level, the proportion between two axillary structure types, i.e. vegetative bud and female flower, was 4.9 in morphotype I, 3.9 and 4.0 in types II and III compared to 1.8 in type IV.