Heat Unit Requirements of “Flame Seedless” Table Grape: A Tool to Predict Its Harvest Period in Protected Cultivation

Abstract

Greenhouse cultivation of table grapes is a challenge due to difficulties imposed by their perennial habit and chilling requirements. Despite difficulties, greenhouse cultivation allows ripening long before that in the open field. Nonetheless, for harvesting “Flame Seedless” in the most profitable periods, a cultural practices timetable has to be established. In this context, an estimation of development rate as a function of temperature becomes essential. This work puts forward a procedure to determine “Flame Seedless” threshold temperatures and heat requirements from bud break to ripening. “Flame Seedless” required an average of 1633 growing degree days (GDD) in the open field with a base temperature of 5 °C and an upper threshold temperature of 30 °C. Strikingly, only 1542 GDD were required within the greenhouse. This procedure forecast “Flame Seedless” ripening with an accuracy of three and six days in the open field and greenhouse, improving predictions based on the average number of days between bud break and ripening. The procedure to predict oncoming harvest date was found satisfactory, just four days earlier than the real date. If we used the typical meteorological year instead of the average year, then the prediction was greatly improved since harvest was forecast just one day before its occurrence.

Ecophysiology and Vegetative and Productive Behavior of 'Chardonnay' Vines under Protected Cultivation Systems in Serra Catarinense of Brazil

“…This difference can be attributed to the increase in temperature under the plastic cover. A similar condition occurred for Alonso et al [35], with seedless grapes produced in a greenhouse. Chavarria et al [25] described the same behavior for 'Moscato Giallo' grapes under protected cultivation in the Serra Gaúcha, and it accelerated the sprouting process and allowed reaching the early maturation stage, considering that the period of regulation in the flowering and fruit ripening period, favors the ripening of grapes under a plastic cover in 10 to 50 days [36,37].…”

Control temperature of greenhouse for higher yield and higher quality grapes production by combining STB in situ service with on time sensor monitoring

“…The effective accumulated temperature requirement for grapes in plastic film-covered facilities is lower than that in open-field conditions. Alonso [ 7 ] estimated the accumulated temperature for the “Flame Seedless” variety under facility production and open field cultivation conditions to be 1542 °C and 1633 °C, respectively, and the effective accumulated temperature for the FM treatment in facilities and the OFM treatment in open field cultivation in this trial year was 1481.7 °C and 1835.3 °C. The slight difference in the calculations is because Alonso used a lower threshold of 5 °C to calculate the effective accumulated temperature from sprouting, whereas this experiment used a lower threshold of 10 °C to calculate the effective accumulated temperature from dormancy, but both showed a lower effective accumulated temperature requirement and earlier maturity in the plastic film covered facility compared to open field.…”

“…With the development of greenhouse structures and equipment materials, the Netherlands and North-Western European Countries are mainly developing Venlo-type modern greenhouses and plant factories [ 6 ]. Modern greenhouses and precise temperature control can be used in the Northern hemisphere to advance the ripening of “Flame Seedless” grapes to the beginning of June [ 7 ]. However, the cost of building a glass greenhouse is high about 668.06 yuan/m 2 [ 8 ] which is not affordable for small farmers.…”