© 1992 Heron Publishing—Victoria, Canada
Effects of water deficit on flower opening in coffee (Coffea arabica L.)
Carlos H. Crisosto (1, 2), David A. Grantz (1, 2, 3) and F. C. Meinzer (4)
1. USDA, ARS, Hawaiian Sugar Planters’ Association, P.O. Box 1057, Aiea, HI 96701, USA / 2. Kearney Agricultural Center, 9240 South Riverbend Avenue, Parlier, CA 93648, USA / 3. Author to whom reprint requests should be addressed / 4. Crop Science Department, Hawaiian Sugar Planters’ Association, P.O. Box 1057, Aiea, HI 96701, USA / Received May 8, 1991
Summary
The response of coffee (Coffea arabica L.) floral buds to different water deficits followed by re-irrigation was investigated. Flower opening was stimulated by
irrigation after one period of water deficit if predawn leaf water potential declined below –0.8 MPa. Similar stimulation
of flowering was observed when less severe but more prolonged water deficits (ca. –0.3 to –0.5 MPa for two weeks) were imposed,
even if water deficit was relieved by re-irrigation several times during this period. Consistent results were obtained in
the field and in two greenhouse locations. Stimulation of flower opening by water deficit followed by re-irrigation was restricted
to buds at the “open white cluster” stage of development (Stage 4). Only buds at this stage exhibited development of secondary
xylem. Split-root experiments indicated that a root signal stimulated flower opening, independently of predawn or midday leaf
water status. Frequent irrigation to prevent flowering, followed by a controlled water deficit and re-irrigation to stimulate
flowering, may represent a practical method to synchronize flowering and shorten the harvest period in leeward coffee production
areas in Hawaii.
