Estimation of fruit tree production by quantitative indicators: the case of lychee in Madagascar
Aina Fehizoro Rabodomanantsoa received her Master’s degree in agricultural sciences on the subject of “Economic valorization of Bourbon geranium essential oil in Madagascar” in 2015. She is currently studying for her PhD on “Forecasting and assessing the lychee yearly production in terms of volume and fruit quality considering a complex system in the east coast region of Madagascar using models to predict more accurately the onset of the harvesting season”. Madagascar is the top exporter of lychee in the world. The country’s yearly exports are approximately 25,000 t, exported mainly to Europe to meet the seasonal consumption of lychee over the end-of-the-year festivities. Lychee production is concentrated in the eastern part of Madagascar and mainly relies on smallholder farmers. Export management is challenging because of climatic variations from season to season, and differences in agricultural practices. Thus, methods and techniques that allow an improved estimation of the lychee production are needed in order to better organize lychee export planning. Thus, the objective of this study was to estimate lychee tree yields prior to harvest. Several tree traits (i.e. basal trunk diameter, diameter at breast height (DBH), canopy diameter, canopy height, number of bunches, load rate) have been considered to estimate the number of fruit per tree and mean fruit weight. A methodology of image analysis based on hue angle criteria was also developed simultaneously to predict individual tree yield. The study was performed on 35 trees of various sizes over two-year harvesting periods. Results indicated that the large variation in yield observed between trees, i.e. from 1 to 860 kg of fruit, was significantly related (R²>0.8) to the DBH, the basal trunk diameter and the number of bunches. However, an effective yield prediction was also obtained by using the volume of the canopy and the fruit load rate as indicators (R²>0.8). Promising results were also obtained using the image analysis methodology that was developed (R²=0.75). These results led to a method that can easily be used to estimate the fruit production of a lychee tree just before harvest, from both the tree structural measurements and/or by using simple images of the lychee tree at harvest taken from two different sides.
Aina Fehizoro Rabodomanantsoa won an ISHS Young Minds Award for the best poster presentation at the VII International Symposium on Tropical and Subtropical Fruits at IHC2018 in Turkey in August 2018.
Aina Fehizoro Rabodomanantsoa, Centre Technique Horticole de Tamatave, Ex bâtiment Opération Café - Boulevard Joffre, 501 Tamatave, Madagascar, e-mail: firstname.lastname@example.org
The article is available in Chronica Horticulturae