Effects of grafting and cytokinin-induced fruit setting on colour and sugar-content traits in glasshouse-grown triploid watermelon

• Published in: The journal of horticultural science & biotechnology 2004, Vol.79 (6), p.971-976
• Main Authors: Lopez-Galarza, S, San Bautista, A, Perez, D.M, Miguel, A, Baixauli, C, Pascual, B, Maroto, J.V, Guardiola, J.L
• Format: Article
• Language: English
• Subjects: application rate; chemical constituents of plants; Citrullus lanatus; color; crop production; crop quality; crop yield; cytokinins; fruit set; fruits (plant anatomy); grafting (plants); greenhouse production; pollination; sugar content; triploidy; watermelons
• ISSN: 1462-0316; 2380-4084
• DOI: 10.1080/14620316.2004.11511875

The effect on fruit quality of grafting and fruit set treatments, was determined in the triploid watermelon (Citrullus lanatus (Thun.) Matsum. and Nakai) cultivar 'Reina de Corazones' grown in a heated greenhouse. Grafting the scion onto 'Shintoza' (Cucurbita maxima × Cucurbita moschata) rootstock and setting fruit through application of the synthetic cytokinin CPPU [1-(2-chloro-4-pyridyl)-3-phenylurea] retarded the accumulation of sugar and development of the flesh colour of the fruit, compared to fruit from non-grafted, pollinated plants. The effects of grafting and of CPPU application on sugar accumulation were additive. At commercial maturity, the fruit of grafted and/or CPPU-treated plants had lower total soluble solids and sugar concentrations, and lower sucrose to hexose ratios, than fruit from control plants. Fruit from CPPU-treated plants also had a weaker red colour than fruit set by pollination. Despite this loss of quality, fruit from grafted plants, set with CPPU and grown in a heated greenhouse, had a total soluble solids concentration similar to fruit from pollinated, non-grafted plants, grown outdoors.