EFFECTS OF WARM AUTUMNS ON THE CROPPING OF PEAR
Experiments were conducted in which potted trees of three cultivars of Pyrus communis were warmed in October and November. This was done at night by covering and heating them within a mobile glasshouse or by moving them into temperature-controlled glasshouses. The temperature regimes used were designed to mimic the 40-year mean maximum temperatures for October and November at East Malling (UK). Warming potted trees of cvs. 'Conference', 'Concorde' and 'Comice' in October and November delayed bud development and the date of full bloom, relative to the unheated control and field-grown trees. With cv. 'Conference' (the earliest flowering cultivar), the earlier warming extended the delay in flowering, accompanied by an increase in initial and final fruit set. Mean fruit yields and the number of fruit per tree were also greater for cv. 'Conference' trees warmed during October, compared with the unheated control trees. Observations with all cvs. suggested that low-temperature injury caused by late spring frost was less frequent in the warmed trees. This could account for the higher yields recorded with cv. 'Conference'. The results of these experiments are discussed in the context of developing a physiological understanding of models developed at HRI-East Malling to account for the observed year-to-year variation in the cropping of Pyrus.
Atkinson, C.J., Lucas, A.S. and Taylor, L. (1997). EFFECTS OF WARM AUTUMNS ON THE CROPPING OF PEAR. Acta Hortic. 451, 743-748
Pyrus communis, temperature