Citrus is one of the world's important fruit crops. Recently, citrus molecular genetics and biotechnology work have been accelerated in the world. Genetic transformation, a biotechnological tool, allows the release of improved cultivars with desirable characteristics in a shorter period of time and therefore may be useful in citrus breeding programs. Citrus transformation has now been achieved in a number of laboratories by various methods. Agrobacterium tumefaciens is used mainly in citrus transformation studies. Particle bombardment, electroporation, A. rhizogenes, and a new method called RNA interference are used in citrus transformation studies in addition to A. tumefaciens. In this review, we illustrate how different gene transformation methods can be employed in different citrus species.

Twenty cyclamen taxa belonging to the Primulaceae originate from the Mediterranean region and grow under trees and bushes. There are 10 cyclamen species growing naturally in Turkey, five of which are endemic. In this study, intact cyclamen plants were collected from nature with their tubers intact. Collection took place in spring and autumn in Adana, Osmaniye, Kahramanmaraş, İzmir and Eskişehir provinces, 50 samples per location. Sampled plants were propagated and cultivated in Adana. The morphology of four Cyclamen species (C. persicum Mill., C. cilicium Boiss.e.Heldr., C. pseudibericum Hildebr. and C. coum Mill.) was characterized using 1-year-old regenerated plants. A total of 27 phenotypic characters (13 flower, 11 leaf, 2 plant, 1 tuber) were evaluated based on a detailed descriptor's list. In addition to these morphological observations, 13 quantitative traits (7 flower, 5 leaf, 1 tuber) were measured. The measurements related to morphological characteristics had a wide range of variation, including in tuber diameter, leaf length and width, petal length, petal color, and leaf shape, indicating the vast morphological differences among these four cyclamen species. In most cases, the use of principal component analysis confirmed the grouping of characters into species-specific clusters although one or two clusters could not differentiate species, indicating that morphological and cluster analyses alone are not enough for characterizing this complex Cyclamen germplasm and that molecular techniques may reveal more intricate and useful relationships.

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The genus Cyclamen (family Myrsinaceae) contains about 20 species, most of which occur in the Mediterranean region. Turkey has critically important Cyclamen genetic resources. Molecular characterization of plant materials collected from different regions of Turkey in which Cyclamen species grow naturally, namely Adana, Antalya, Aydın, Muğla, İzmir, Denizli, Kahramanmaraş, Osmaniye, Eskişehir, Trabzon, and Rize provinces, was performed using RAPD and SRAP markers. DNA was successfully amplified by 30 RAPD primers and 14 SRAP primer pairs. Among the 470 bands generated by the RAPD primers, 467 were polymorphic. The number of bands detected by a single primer set ranged from 11 to 22 (average of 15.6). The percentage polymorphism was 99.3 % based on the RAPD data. In the SRAP analysis, a total of 216 bands were generated, showing 100 % polymorphism. The number of bands detected by a single primer set ranged from 9 to 22 (average of 15.4). All data were scored and UPGMA dendrograms were constructed with similar results in both marker systems, i.e., different species from nine provinces of Turkey were separated from each other in the dendrograms with the same species being clustered together.

Plant genetic resources conservation may be a potential option for the improvement of agricultural crops through modern biotechnologies, and in vitro conservation is a tool available to safeguard plant biodiversity. Ex situ conservation of plant genetic resources using the in vitro procedures is in progress in many countries. The slow growth storage (SGS) technique is a valid in vitro approach to preserve several vegetatively propagated species by controlling the growth and development of plantlets, economizing storage space and labor and reducing costs. Moreover, SGS prolongs the timing between subcultures, lowers the risk of losing germplasm through handling errors, such as contamination problems, and decreases the risk of genetic instability due to the reduction in the number of subcultures. SGS is applied by considering different factors: temperature, light or darkness conditions, medium composition, including mineral or sucrose concentrations, and the presence/absence of plant growth regulators, osmotic agents and growth inhibitors. SGS protocols for some fruit species have been well defined, others require additional research. The present review focuses on the effect of several factors that influence the SGS of in vitro shoots derived from temperate and tropical fruit species during the last ten years.