Papaya (Carica papaya L.) Phenology under Different Agronomic Conditions in the Subtropics

Juan Alberto Cabrera,María Gloria Lobo,Eudaldo Pérez,Vanesa Raya,Axel Ritter

doi:10.3390/agriculture11020173

Juan Alberto Cabrera, María Gloria Lobo + Show 3 more

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https://doi.org/10.3390/agriculture11020173

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Abstract

European consumers have perceived that papaya fruits produced in subtropical areas (the Canary Islands and Mediterranean regions) do not have the desired quality at certain periods of the year. Thus, the development of technical and management strategies to optimize the yield and the quality of the fruit requires crop phenology studies. Meteorological variables (air temperature, relative humidity, and photosynthetically active radiation) and morphological characteristics (plant height, leaf emission rate, and leaf area) were recorded throughout the crop cycle. All the leaves and fruits were labeled in their anthesis week to calculate the source–sink ratio and to study the development and quality of the fruits. Data were collected in three commercial orchards representing two different types of systems, greenhouse and screenhouse, and two different regions: two plastic cover greenhouses located in the south (SP) and in the north (NP) of Tenerife, and one 40-mesh net screenhouse in the north of the island (NN). The selection of these cultivation systems and locations was made deliberately, so that the ambient variables within these crop protection structures were different throughout the cultivation cycle in order to better fit the model construction. The results suggested that in order to maintain good fruit quality, better environmental control is necessary inside the greenhouses and the screenhouse. Monitoring variables such as the growing degree days, the photosynthetically active radiation, and the number of fruits per plant leaf area ratio provided useful information for papaya production management in the Canary Islands and other subtropical areas, allowing farmers to predict harvest and fruit quality.

Highlights

The results of this study suggested that monitoring growing degree days (GDD), daily photosynthetically active radiation (PAR) integral, and leaf area (LA) inside the greenhouses or the screenhouse could be a useful tool for predicting harvests by determining the fruit development days (FDD)
The analysis of factors affecting flower and fruit setting and yield pattern in papaya crops growing under different agronomic conditions could provide useful information for harvest planning and prediction in papaya commercial crops
A model to predict the period of fruit development was established based on data from anthesis week, total growing degree days, total daily photosynthetically active radiation, and plant leaf area

Summary

Introduction

Papaya (Carica papaya L.) cultivation has increased rapidly, even in subtropical areas, due to its beneficial properties: nutraceutical (i.e., contains considerable concentrations of proteolytic enzymes such as papain and chymopapain); antiviral, antifungal, and antibacterial properties; it contains vitamins, bioactive compounds, and a lipidic composition that reduces inflammatory markers and anti-platelet aggregation, protects against thrombogenesis and oxidative stress, and prevents hypercholesterolemia [1,2].Spain is the largest papaya producer in Europe (350 ha, with an annual production of around 15,000 tons), the Canary Islands being the largest producer (farms totalizing 300 ha).In the South-East of Spain, Sicily, or Turkey, the cultivation of papaya is growing as an economic opportunity, due to its proximity to the European market, and to diversify agricultural production.In the subtropics, papaya must be produced inside environment modification structures, such as greenhouses or screenhouses, in order to adjust the meteorological conditions to the crop requirements to obtain optimal fruit production and quality. Spain is the largest papaya producer in Europe (350 ha, with an annual production of around 15,000 tons), the Canary Islands being the largest producer (farms totalizing 300 ha). In the South-East of Spain, Sicily, or Turkey, the cultivation of papaya is growing as an economic opportunity, due to its proximity to the European market, and to diversify agricultural production. Papaya must be produced inside environment modification structures, such as greenhouses or screenhouses, in order to adjust the meteorological conditions to the crop requirements to obtain optimal fruit production and quality. Poor quality can lead to consumer rejection, with consequent economic losses and mistrust in papaya of subtropical origin. Greenhouses reduce water consumption and provide protection to prevent foliage damage due to the effects of wind and the Papaya ringspot virus (PRV) [3]

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