New Lemon Genotype for Ornamental Use Obtained from Gamma Irradiation

Some citrus species and cultivars with attractive appearance of fruits and leaves have been used for ornamental purposes. Some of them have small fruits and plant size and mixed color of leaves or fruits. Here, we report a new lemon genotype with potential use for ornamental purposes. This genotype was obtained exposing 'Kutdiken' lemon cultivar budwood to gamma irradiation. This cultivar is widely grown in Turkey because of its high yield and good quality fruits. Fruits of the new genotype have attractive appearance with vertical brown lines and brown point heaps. Differences of fruit rind of this genotype have originated from mutation(s) caused by gamma irradiation

Hybridization-Based Citrus Breeding Program in Turkey

Breeding studies to develop new citrus cultivars have been carried out using some traditional methods such as selection, mutation and hybridization. The hybridization approach has been common in mandarin breeding programs. Mandarins are mostly preferred for fresh consumption since they have easy peeling features. A hybridization-based mandarin breeding program has been carried out in Turkey for the last ten years. 'Clementine' mandarin was used as female parent and many cultivars of various species were used as male parents. Over 4000 hybrids have been evaluated so far and the work are still on-going. Up to now, several promising hybrids with different characteristics have been selected. Genotype "336" from a 'Clementine' x 'Orlando' tangelo cross is the most promising hybrid with large fruits (175 g), dark orange rind color and early maturity (October). Hybrid genotype "20-2" from a 'Clementine' x 'Valencia' orange cross was found to be late maturing (April) and it has large fruits and good appearance. The hybrid "39-9" from a 'Clementine' x 'Cocktail' grapefruit cross has very large fruits (244 g) and attractive shape and it is harvested in November. "CO-44", another hybrid from a 'Clementine' x 'Orlando' tangelo has large (167 g) and early maturing fruits (October). In addition to these hybrids, many genotypes have been preselected with good characteristics. In the near future, new superior cultivars may be released

QTL analysis and regression model for estimating fruit setting in young Citrus trees based on molecular markers

This study was conducted to assess the genetic basis and develop a regression model for a QTL trait, fruit setting of a full sib population of 164 hybrids obtained between 'Clementine' mandarin (Citrus reticulata Blanco 'Clementine) and 'Orlando' tangelo' (Citrus paradisi Macf. 'Duncan' x C. reticulata Blanco 'Dancy'). Fruit setting of a 164 full sib population field-planted in 2007 was evaluated by visual counting of fruits in 2008, 2009, and 2010. We estimated linkage groups and effects of QTLs by using MapQTL5. Based on interval mapping, seven linkage groups of the maternal and eight linkage groups of the paternal maps harboured QTLs of the fruits setting, covering a total 300 of 1744 cM Citrus map. Only three segments were associated with all three-year data (one in 'Clementine' and two in 'Orlando' map) spanning 60 cM of 1744 cM of Citrus linkage map. Twenty-seven (17%) and 13 (8%) hybrids consistently produced less than 5 fruits and the highest number of fruits (>= 50) in their 2nd. 3rd, and 4th ages. Based on BACKWARD elimination procedure of PROC REG option nested in SAS program, regression models constructed for 2008, 2009, and 2010s fruit setting explained 35, 81, and 38% of the total phenotypic variation (R(2)) observed in the 164 full-sib hybrids, respectively (P <= 0.05). This study indicated that early fruit setting was a complex trait affected by many QTLs and the regression model developed in this study might be used to predict performances of hybrids with similar genetic background. (C) 2011 Elsevier B.V. All rights reserved

Developing, linkage mapping and phylogenetic analyses of AP2-EREBP type transcription factor markers in citrus

Ethylene responsive AP2/EREBP type transcription factors (TF) play major roles such as growth, development, and tolerance to biotic and abiotic stresses in plants. Forward and reverse AP2/EREBP type TF-specific primers were designed, sequenced, and linkage mapped in a population of 164 F-1 individuals derived between 'Clementine' mandarin (Citrus reticulata Blanco 'Clementine') and 'Orlando' tangelo' (C. paradisi Macf. 'Duncan' x C. reticulata Blanco 'Dancy'). A total of 26 pairs of primers were designed for PCR reactions using Primique software available in TF database (DATFAP) based on default parameters using available dicot's AP2/EREBP sequences. These primers included 17 to 35 bases, and produced a total of 21 polymorphic markers. Bright 13 markers were excised, sequenced, deposited in the NCBI web site, and BLAST-analyzed for homology. Of the 21 markers, 13 were linkage mapped in a previous citrus map. Seven and five markers were mapped in 'Clementine' and 'Orlando' map, respectively. Based on Maximum Parsimony algorithm nested in MEGA 4 evolutionary genetic analysis software, the 13 TF sequences obtained in this study were found to be closely related to known TFs of Arabidopsis thaliana. Few of TF markers were found to be closely linked in existing linkage map of citrus, suggesting possible ancestral origin. These AP2/EREBP primers helped identification of citrus AP2/EREBP type transcription factor genes and can be used in other dicots such as tomato and cotton may have potential in understanding evolutionary relationships, establishing linkage map, and estimating diversity among other dicots since these TFs may reflect adaptability of plants

Evaluation of 'Clementine' x 'Kara' Mandarin Hybrids

Mandarin is one of the most important citrus fruit and has been subject to various breeding research to obtain new cultivars through hybridization. A mandarin breeding program has been going on for a long time in Alata Horticultural Research Station, Mersin, Turkey. In the program, a lot of cultivars have been used as parents. In the present study, the results obtained by crossing a monoembryonic 'Clementine' and late-maturing 'Kara' mandarin is reported. One hundred and seventeen hybrids and the two parents were evaluated for their fruit characteristics during four years. Important variations in fruit parameters were observed between the hybrids. Fruit weight of hybrid plants ranged between 44 and 231 g. Number of seeds varied from 3.8 to 45.8 whereas juice content ranged between 13.6 and 61.0%. According to four years of observations, harvest period of hybrids extended from mid-October to end of February