Basal temperature and thermal sum in phenological phases of nectarine and peach cultivars

Abstract

The objective of this work was to evaluate basal temperature, thermal sum at different phenologicalstages, phenological phase duration, yield and seasonality of one nectarine and 14 peach cultivars, between2006 and 2009. The considered phenological phases were: pruning-sprouting; sprouting-flowering, fromswollen bud to open flower; flowering-fruiting, from petal fall to medium‑sized fruit; and ripening. Minimumbasal temperatures (Tb) obtained were: pruning-sprouting, 8°C, irrespective of the cultivars; sproutingflowering,10°C, except for 'Cascata 968', which required 8°C Tb; flowering-fruiting, 12°C, except for 'OroAzteca', which required 14°C Tb; ripening, 14°C, except for 'Sunblaze', 'Diamante Mejorado' and 'Precocinho'with 12°C Tb. For most cultivars, the maximum basal temperatures were 30, 34, 34 and 28ºC for phasespruning-sprouting, sprouting-flowering, flowering-fruiting and ripening, respectively. 'Turmalina', 'Marli' and'Tropic Beauty' showed average yields of 3,945.0, 3,969.3 and 3,954.0 kg ha^‑1, respectively, in 2009, while thenectarine 'Sunblaze' showed around 3,900 kg ha^‑1 in 2008 and 2009. The cultivars differed for their total cycleand for the accumulated thermal sums which varied, respectively, from 245 days and 1,881.4 degree‑days for'Oro Azteca', to144 days and 1,455.7 degree‑days for 'Precocinho'.