|Matsumoto Brower, Tracie|
|Lopez, Johnny - Valent Biosciences-Usa|
Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/2016
Publication Date: 12/9/2016
Citation: Matsumoto, T.K., Lopez, J. 2016. Coffee harvest management by manipulation of coffee flowering with plant growth regulators. Acta Horticulturae. 1130:219-224.
Interpretive Summary: Coffee flowering occurs after the plants experience a drought followed by rainfall. Sporadic rainfall is thought to be responsible for multiple flowering, thus resulting is coffee cherries at different stages of development on the same tree. Due to this difference in coffee cherry maturity, the trees need to be harvested multiple times which increase labor costs. Having ripe, green and immature coffee cherries on the same trees also provides a constant food source for the Coffee Berry Borer (CBB). In our experiments we have found that sprays containing the gibberellic acid or abscisic acid, two naturally occurring plant hormones, can promote coffee flowering and subsequent coffee cherry harvests.
Technical Abstract: The breaking of coffee flower bud dormancy is known to be associated with one or more significant rainfall events following an extended period of dryness. In Hawaii, lack of a distinct wet-dry season poses serious problems for coffee growers because flowering is spread over several months. Multiple flowering episodes stem from the progressive development of buds located in leaf axils of lateral branches. Flower bud development occurs as branches lengthen and grow outwards. Higher elevation and/or higher latitude generally slow the growth of both branches and their buds. Hence older mature buds are found on the inner portions of lateral branches while younger immature buds are found on outer and top branches of the trees. Multiple flowering episodes forces 3-5 harvest rounds on the same tree during the harvest season. This increases labor costs in both hand and mechanically harvested coffee farms. In addition, the constant presence of coffee berries in the field increases coffee berry borer (CBB) reservoirs in the field. In a series of trials Kona Coffee trees treated with foliar sprays of GA3 resulted in more concentrated flowering. Coffee harvests were shown to be more uniform with higher recoveries of ripe berries. Additionally, soil drenches and foliar sprays of s-ABA increased coffee yields on trees treated in Kona and Kauai. Here we present data on current experiments in Hawaii to optimize rates and timing of GA3 and s-ABA sprays on semi-commercial field plots.