Effects of the size of papaya (Carica papaya L.) seedling with early determination of sex on the yield and the quality in a greenhouse cultivation in continental Europe

Abstract

One of the major problems when planting papaya using traditional methods is sex identification of the plant to obtain the highest yield from hermaphrodite fruits. The problem derives from the competence between plants, before sex identification, when three to four plants are planted together. This problem was solved applying a R.A.P.D. technique (Randomly Amplified Polymorphic DNA) in early sex-identification in the laboratory of the nursery with the first true leaf of the plant. Furthermore, economic costs and wasted vegetal material caused by removing female plants from production can be avoided by grafting hermaphrodite plants onto female plants. The nursery facilities for horticultural plants in Almería allow herbaceous grafting work, as well as the production of balanced relationship between aerial and root biomass. For this reason, an experiment was conducted to evaluate yield parameters in the planting of large and small, sex-identified plants. The plants grown were the main papaya cultivar produced in Continental Europe, called ‘Intenzza’, and a new cultivar called ‘Sweet Sense’. Within a greenhouse cultivation system in the South of Europe, the early stage sex-identified plants transplanted as “large plant” size gave higher yields in contrast with traditional methods of planting papaya, but the technique does not affect fruit size and retains sweetness. From a morphological point of view, although the growing and development technique is different it does not cause significant differences in the papaya by the time of harvest.