Flowering of 'Ponkan' mandarin (Citrus reticulata Blanco) submitted to differents periods of winter temperature

This work aimed to evaluate the effect of low temperature accumulation below 20 degrees C, on the flowering of mandarin (Citrus reticulata Blanco cv. 'Ponkan'). A completely randomized design with six treatments and four replications was used in this experiment. The treatments comprised seven different dates of transferase of 'Ponkan' plants growing in open field into growth room. The 'Ponkan trees used in this experiment were originated from grafting onto Rangpur lime, growing in containers. The experiment began on 05-16-2007, when the cold season initiated. In 15-days intervals, four plants were removed randomly from the open field and taken into the growth room, with controlled temperature and humidity. The date of the flowering and total number of flowers were evaluated. The longest time of maintenance of the plants in the open field in temperatures below 20 degrees C advanced the flowering and increased the number of produced flowers.