1. Investigation the predecessor and nitrogen fertilization influence on the productivity of triticale variety Bumerang

The field experiment was held in the experimental of the selected area in Polyanovo village (South Bulgaria) in the period 2013–2016. The randomized complete block design with 4 replications and 25 m2 plot size was applied. The sowing was made with 550 seeds/m2 after three predecessor – sunflower, barley and coriander and three rates of nitrogen fertilization – 80, 120, 60 kg/ha and control N0. The investigation aim was to establish the effect of predecessor and rates of nitrogen fertilization on the structural elements and the yield of triticale variety Bumerang in South Bulgaria. All the stages of the established technology for wheat growing were followed. The grain yield is determined with standard grain moisture of 13%. The indices; the number of productive tillers (m2), the height of plants (cm), length of the spike (cm), the number of spikelets per spike, number of grains per spike, the weight of the grains per spike (g) and grain yield (kg ha-1) were determined. The analysis of the results shows that both the experimental factors (predecessor and nitrogen fertilization) in combination with meteorological conditions during the years of the study had a significant influence on yield and yield components of triticale variety Bumerang. The most suitable predecessor for triticale variety Bumerang under the conditions of South Bulgaria is coriander, followed by sunflower and barley. The most effective fertilization rates are N120 with predecessor coriander and N160 with sunflower and barley.