Turkey is an important citrus-producing country. However, new cultivars are needed to sustain citrus production and ensure its competitiveness against other crops. There are currently several citrus breeding programs that aim to help overcome the lack of local commercial varieties and to contribute to Turkey’s competitive capacity in the citrus market. In this study, we report the utilization of molecular markers in one such breeding program. Simple sequence repeat (SSR) markers were employed to eliminate nucellar individuals from a hybrid population produced by crossing. The crosses included ‘Fremont’ and ‘Robinson’ mandarins as the female parents and ‘Midknight Valencia’, ‘Rhode Red Valencia’, and ‘Valencia Late’ oranges and ‘Rio Red’ grapefruit cultivars as the male parents. Seedlings with the same banding patterns as the female parent were identified as nucellar seedlings by 11 SSR primers. Primers AG14 and TAA03 were found to be more effective at identifying zygotic individuals than other primers. ‘Fremont’ and ‘Robinson’ mandarins produced 36.91% and 31.09% of nucellar seedlings, respectively. As a pollen parent, ‘Rio Red’ grapefruit had a higher ratio of zygotic seedlings compared to ‘Midknight Valencia’, and can be recommended in breeding programs. Comparative analysis of different citrus fruits in the breeding programs allowed us to design an efficient hybridization scheme for this study.

Na uptake was superior on the other rootstocks. It was observed that 'Carrizo' and 'Troyer' citrange rootstocks had advantages over sour orange in nutrient uptake. Thus, growth performance, yield, and quality parameters considered, 'Carrizo' and/or 'Troyer' citranges could be suggested as rootstocks for the studied mandarin cultivars under similar ecological conditions.

The plant growth, yield, yield efficiency, and fruit quality of 'Rhode Red Valencia' and 'Valencia Late' sweet oranges (Citrus sinensis (L.) Osbeck) on three rootstocks were evaluated under Eastern Mediterranean climatic conditions of Dörtyol-Hatay, which is one of the oldest and largest citrus and mandarin (Citrus reticulata Blanco) production regions in Turkey. The fruit yield was affected by rootstock in both scion cultivars from 2007 through 2010. Trees on 'Troyer' citrange had lower yield than those budded on the other rootstocks. The yield of 'Rhode Red Valencia' and 'Valencia Late' orange trees on 'Carrizo' citrange were about 9% and 19% more than those on 'Troyer' citrange, respectively. But trees on 'Troyer' citrange had significant higher yield efficiency than trees on sour orange and 'Carrizo' citrange, because of canopy volume of 'Troyer' citrange was lower than the other rootstocks. The heaviest fruits of 'Valencia Late' orange trees were harvested from 'Carrizo' citrange (214.69 g), while 'Rhode Red Valencia' orange trees did not show differences regarding the rootstock. The rootstocks had no significant effects on juice content of 'Rhode Red Valencia' and 'Valencia Late' oranges. The effects of the rootstocks in both scion cultivars on juice content, total acids (TA), Brix:TA ratio, and number of seeds per fruit were found to be insignificant.

2 Rootstock selection has a critical importance for mineral nutrition of budded cultivars. This study was conducted at the experimental farm of Mustafa Kemal University, Dörtyol, Turkey. The aim of this study was to investigate the effect of sour orange, Troyer and Carrizo citrange rootstocks on the leaf nutrient contents of 'Nova', 'Robinson', and 'Fremont' mandarin cultivars in the 2004 and 2005 growing seasons. Carrizo citrange was examined for nitrogen (N), potassium (K), magnesium (Mg), sodium (Na), and manganese (Mn); Troyer citrange for iron (Fe); and sour orange for calcium (Ca) and zinc (Zn) were superior on the others. Nitrogen, phosphorus (P) andMg levels of mandarin leaf budded on sour orange were under or just above the deficiency threshold. Potassium, Mn, and Zn content of 'Robinson'; P, Ca and Fe content of 'Fremont'; and Cu content of 'Nova' were statistically higher. Therefore, it can be concluded that Carrizo rootstock may be suggested for the region and regions with similar ecological conditions.

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