Use of a Phenological Model to Time Acceleration of Pollinizer Bloom

Abstract A pear anthesis phenology model was used to determine timing of placement of reflector boards near ‘Seckel’ pear trees, or polyethylene hotcaps over them to accelerate their bloom for optimum pollination of ‘Anjou’. The normal full bloom date of ‘Anjou’ was predicted from the Utah chill unit (CU) and growing degree hour (GDH) models. ‘Bartlett’ pear phenology and historical bloom divergence of ‘Seckel’ and ‘Anjou’ were used in the absence of ‘Seckel’ and ‘Anjou’ phenology to determine the timing and amount of supplemental thermal accumulation. Bloom-accelerating techniques were placed on the pollinizer trees at an intermediate anthesis stage. Polyethylene hotcaps accelerated bloom effectively.