Yield and fruit quality of 'Nova' hybrid [Citrus clementina hort. ex Tanaka x (C. reticulata Blanco x C. paradisi Macfad)] and two Clementine varieties (C. clementina hort. ex Tanaka) as affected by self- and cross-pollination

Low yields of 'Nova' citrus hybrid are common in single variety plantings (plantings consisting of one variety) due to its sexual self-incompatibility. Self-incompatibility may be overcome by cross-pollination with other compatible varieties. Fruit quality and yield of 'Nova' citrus hybrid as well as of the 'SRA63' and 'Marisol' Clementines, when either they were self-pollinated in single variety plantings or each one of the two Clementine varieties was used as a pollenizer for 'Nova' in mixed plantings (plantings consisting of more than one variety), were investigated. The study was carried out for two successive years under the same environmental and cultural conditions using three single variety plantings ('Nova' x 'Nova', 'SRA63' x 'SRA63','Marisol' x 'Marisol') and two mixed plantings ('Nova' x 'SRA63', 'Nova' x 'Marisol'). Cross-pollination of 'Nova' with either 'SRA63' or 'Marisol' significantly increased fruit yield of 'Nova' trees and mean fresh weight of 'Nova' fruits without affecting the other fruit quality parameters [rind thickness, percentage of juice, concentration of total soluble solids (TSS) and total acids (TA) in the juice, and TSS/TA ratio). Although the number of seeds per each 'Nova' fruit significantly increased due to cross-pollination (from 0.7 in 'Nova' x 'Nova' planting to 1.8 and 2.1 in 'Nova' x 'Marisol' and 'Nova' x 'SRA63' plantings, respectively), it remained in a range (<= 2.1) which is by far acceptable in the fresh fruit market. On the other hand, each fruit produced by cross-pollinated 'Marisol' and 'SRA63' trees with 'Nova' contained an average of 2.4 and 18.6 seeds, respectively. The effects of 'Nova' pollen on the other fruit quality parameters (weight, TSS, TA, TSS/TA, juice content, rind thickness) of 'Marisol' and 'SRA63' were not significant. Therefore, 'Marisol' was proved to be a good pollenizer for 'Nova' and vice versa. Furthermore, 'SRA63' can be used as pollenizer in 'Nova' orchards. Instead, the use of 'Nova' trees as pollenizers in 'SRA63' orchards should be avoided since the seediness of 'SRA63' fruits was increased very much. (C) 2009 Elsevier B.V. All rights reserved.