TEMPERATURE AFFECTS VEGETATIVE GROWTH AND FLOWERING OF COFFEE (COFFEA-ARABICA L)

The effect of temperature was investigated on the vegetative growth and flowering of nine coffee cultivars (Catuai Rojo, Catuai, Caturra Amarillo, Caturra Rojo, Catimor, BMK, SL6, K7 and LB) grown in pots under glass. High day/night temperatures (33 degrees/28 degrees compared with 18 degrees/13 degrees, 23 degrees/18 degrees and 28 degrees/23 degrees C) accelerated stem extension and node production. Growth was greatest in cvs K7 and SL6 and lowest in cv. Caturra Rojo. Prolonged exposure to high temperatures of 33 degrees/28 degrees C accelerated leaf loss and induced a general decline in tree health. All cultivars showed rapid initial growth during summer and autumn, and slower growth during winter and spring under short days (<13 h) and low irradiances (<6.8 MJ m(-2) d(-1)). Growth did not recover in spring and summer at the end of the experiment. Inflorescences were initiated mainly from April to September under photoperiods <12 h. More floral buds initiated at 23 degrees/18 degrees C and 18 degrees/13 degrees C than at 28 degrees/23 degrees C and no floral initiation occurred at 33 degrees/28 degrees C. Inflorescence development took 4-6 weeks at 28 degrees/23 degrees compared with 8-10 weeks at 23 degrees/18 degrees and 12-14 weeks at 18 degrees/13 degrees C. High temperatures also induced floral malformations. Cvs Catuai Rojo, Caturra Rojo and Caturra Amarillo had most inflorescences per node and cvs K7, BMK and LB fewest. Temperatures of 33 degrees/28 degrees C during summer will ensure maximum vegetative growth and potential number of flowering nodes. Temperatures of 23 degrees/18 degrees C during winter will ensure healthy and synchronized floral bud development and maximize the number of inflorescences per node.