Selection of traditional varieties and breeding of new cucurbit varieties adapted to organic production
- Autores: Rocío Alejandra Flores León
- Directores de la Tesis: María Belén Pico Sirvent (dir. tes.)
- Lectura: En la Universitat Politècnica de València ( España ) en 2023
- Idioma: español
- Tribunal Calificador de la Tesis: Almudena Lázaro Lázaro (presid.), Ángeles Alonso Moraga (secret.), Francisco Ribas Elcorobarrutia (voc.)
- Programa de doctorado: Programa de Doctorado en Biotecnología por la Universitat Politècnica de València
- Materias:
- Enlaces
- Tesis en acceso abierto en: RiuNet
- Resumen
Melon (Cucumis melo L.) is one of the main crops belonging to the Cucurbitaceae family, of which Spain represents one of the secondary centres of diversification, where unsweet (Flexuosus) and sweet (Ibericus) melons are still cultivated. Nowadays, cultivation of traditional melon landraces has been replaced by commercial F1 varieties of the Piel de Sapo and Amarillo subgroups. In order to promote and recover these traditional landraces, would be through organic farming. There are a number of factors which limit the cultivation of these traditional landraces, both biotic and abiotic factors. The use of grafting could be a method to help with these stresses. Grafting and abiotic stresses can have an effect different quality fruit parameters. For this reason, the genetics, morphology and acid, sugar and volatile profiles of a collection of traditional Spanish melon landraces, both sweet and non-sweet, have been analysed in this doctoral thesis. In addition, the effect of salinity and different rootstocks on agronomic, morphological and metabolic factors has been studied. Genetic analyses differentiated between exotic materials, Flexuosus and Ibericus accessions. In the case of Ibericus, it was not possible to find a clear distinction between the different subgroups. Morphological differences between and within subgroups were also found. The main volatile organic compounds (VOCs) detected in the non-sweet fruits (Flexuosus and Chate) were aldehydes and alcohols, being able to differentiate between them. A high level of variability was observed in the VOCs profile of sweet Ibericus. The performance of both grafted alficoz and grafted sweet melon cultivars was evaluated under organic farming conditions. In both cases, soil pathogens and viruses were found to be the main limiting factors. Regarding viruses, the main one was Watermelon Mosaic Virus (WMV), followed by Zucchini Yellow Mosaic Virus (ZYMV), Tomato Leaf Curl New Delhi Virus (ToLCNDV) and Cucurbit aphid-borne yellows virus (CABYV). The main airborne fungus detected was powdery mildew caused by Podosphaera xanthii. As for soilborne pathogenic fungi, Macrophomina phaseolina and Fusarium species, Neocosmospora keratoplastica and N. falciformis, reduced yields, in synergy with high salinity. In this case, Cucurbita rootstocks performed worse than Cucumis rootstocks. Likewise, Cucumis rootstocks obtained fruit characteristics similar to ungrafted fruit or improved the quality of some parameters. The resistance of a Spanish alficoz variety to four pathogens (M. phaseolina, Monosporascus cannonballus, N. keratoplastica and N. falciformis) has also been evaluated. Regarding the effect on metabolites, the use of grafting affected the acid, sugar and VOCs profiles of alficoz. Cucurbita grafted fruits resulted in lower perception during tasting, due to odd flavours, while Cucumis did not have that effect, resulting in similar scores to ungrafted fruits. In sweet Ibericus melons, the main factor changing the metabolite profiles was the cultivar, both for acids and sugars. The effect of grafting was minimal, whereas salinity had a greater effect. The effect on VOCs was also highly dependent on the rootstock-variety combination, with the same rootstock showing different effects depending on the variety on which it was grown.
