Citrus somatic hybridization with potential for direct tetraploid scion cultivar development

Protoplast fusion has been an effective tool with several applications for citrus cultivar improvement. The evaluation of fruit characteristics of certain previously produced citrus somatic hybrids with 'Page' tangelo or'Murcott' tangor as parents, has shown that some allotetraploids produce high quality fruit with direct fresh-fruit cultivar potential. Based on this information, additional somatic hybrids combining these parents with other high quality scions were produced as follows: 'Murcott' tangor + 'Dancy' tangerine, 'Murcott' + LB8-8 ('Clementine' X 'Minneola'), 'Page' tangelo + 'Murcott','Page' + LB8-9 ('Clementine' X 'Minneola'),'Page' + ('Clementine' X 'Satsuma'),'Page' + Orie Lee hybrid ('Clementine' X 'Murcott'), and 'Page' + 'Ortanique' tangor, respectively. Their tetraploid level was confirmed by flow cytometry, and their hybridity was verified by random amplified polymorphic DNA (RAPD) or simple sequence repeat (SSR) analysis. Polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) analysis from mitochondria (mt) and chloroplast (cp) DNA, and cpSSR analysis, were also applied to analyse their cytoplasmic genomes. These new hybrids have potential for good quality fruit with reduced seed numbers, and can also serve as tetraploid breeding parents for subsequent triploid production.