The improvement in papaya cultivation and the increase in papaya production have been in the news at the research journal Scientia HorticulturaeThe results of the collaboration between the University of California at Berkeley and the University of California at San Diego (U.S.A.) are presented in an article published in the AGR-200 Research Group of the University of Almeria and the Vitalplant Seedbed. The researchers Mireille Honoré, Luis Belmonte and Francisco Camachoas well as Asensio NavarroVitalplant manager and graduate of the Escuela Superior de Ingeniería de la Universidad de Chile. UALThe study 'Influence of early sexing and plant size of papaya on yield and fruit quality in a greenhouse crop in Continental Europe'.

In order to achieve the desired objectives of optimizing the papaya cultivation under greenhouseIn addition, a series of specific cultural practices were followed, some of which were adapted to those applied to our horticultural plants. Thus, every plant that was used for the cultivation was early sexing through molecular techniques when it was still in the seedbed, so that only one hermaphrodite plant was transplanted per stroke, avoiding sexing in the field when 3-4 plants were previously transplanted. Since hermaphrodite plants are the ones that produce the best fruits and those demanded by consumers.

In addition, the withdrawal from the production market of female plants represents a economic cost and waste of plant materialThis can be solved by grafting a hermaphrodite plant onto a female plant. In this sense, the seedbed facilities for horticultural plants in Almeria offer some of the best solutions in the market. great possibilities for herbaceous grafting worksas well as possibilities to realize balanced plants with the ratio of aerial biomass to root biomass.

The process of papaya cultivation

The experiments in relation to papaya cultivation were carried out at the 'Catedrático Eduardo Fernández' farm at the Fundación UAL-Anecoop, with a total ofThe planting was carried out under greenhouse in a 1,800 m2 multitunnel type greenhouse, with a height to the gutter of 4.50 meters and a height to the ridge of 5.70 meters, covered with 800-gauge plastic sheeting. The soil was sandblasted and drip irrigation was used. The cultivars used were Intenzza and Sweet Sense. Plants of two different sizes were used, 20 and 60 centimeters high, with root balls of 0.133 and 2 liters respectively.

Plant material was transplanted on March 23, 2016 and removed on June 15, 2018.. The plant distribution was made in staggered paired rows, with a distance between paired rows of 2.20 meters (aisles), between rows of one meter and between plants of two meters. With this distribution, the density was 2,700 plants per hectare. Likewise, the nutrition of the papaya crop was done by fertigation using a nutritive solution made ad hoc and named 'Uniqua Trop ®' from Megasa; with the following characteristics: NPK+Ca+Mg: 2.9 - 1.3 - 5.7 (2.2 - 0.5). Pathological problems were solved by releasing auxiliary insects and applying plant extracts. The fruits were harvested during the months of October 2016 to mid-June 2018.

For its part, the parameters evaluated were The total production (kg), average fruit weight and number of fruits per plant, control of the level of soluble solids in the fruit, and plant morphology data were also collected. Plant morphology data were also collected, specifically: height from the peduncle of the first fruit harvested to the ground, number of nodes from the ground to where the first fruit was harvested and perimeter of the stem at 10 centimeters from the ground. All data obtained were subjected to the corresponding statistical analysis.

Thus, yield results ranged, depending on the production system selectedThe yield per hectare is between 262.8 and 325.22 tons per hectare. These data for papaya cultivation are superior to those obtained in other countries such as Costa Rica, Mexico, India and Florida (USA). Thus, from the experiment it was concluded that the production obtained using early sexed plants transplanted with a large root ball is superior to all the reports consulted on this parameter in papaya cultivation in other continents.

It should also be noted that, with respect to to the average fruit weightThis data coincides with those obtained by various researchers, both in the Canary Islands and in other countries of America and Asia. The soluble solids obtained were similar to those obtained for the varieties tested by other researchers for the same varieties, both in insular Spain and in other American countries. On the other hand, as regards the height at which the plant starts to produceIt was found that the transplanting carried out with large plants and in balance between aerial and root biomass tended to bear fruit lower and at a node closer to the ground, being earlier with respect to the planting date. However, the different treatments used in the agricultural production system of southeastern Spain had no influence on average fruit weight or soluble solids content, parameters that depend much more on genetic components than on the treatments used in this cropping system.