Aydin Uzun

Evaluation of Genetic Diversity in Lemons and Some of Their Relatives Based on SRAP and SSR Markers

Genetic diversity was evaluated by sequence-related amplified polymorphism (SRAP) and simple sequence repeat (SSR) markers among 45 lemons (Citrus limon (L.) Burm. f.), five citrons (Citrus medica L.), four rough lemons (Citrus jambhiri Lush), and two Citrus volkameriana accessions. Twenty-one SRAP primer combinations produced a total of 141 (77%) polymorphic fragments with an average of 6.7 fragments per primer combinations whereas 13 SSR primers produced a total of 26 (76%) polymorphic fragments with an average of 2.0 per primer. The unweighted pair-group method arithmetic average analysis as assessed with combined SRAP and SSR data demonstrated that the accessions had a similarity range from 0.65 to 1.00. Rough lemons and C. volkameriana accessions were relatively closely related. In lemon group, accessions from hybrid origin were distant from the others. We also applied principal components analysis (PCA) for a better presentation of relation among the accessions studies. Using PCA, 88.7% of the total variation in the original dimensions could be represented by just the two dimensions defined by the first two PCs. Although nearly all accessions could be distinguished, there was a low level of genetic diversity detected among lemon cultivars.

Genetic Diversity in Citrus

The genus Citrus L. belongs to the subtribe Citrineae, the tribe Citreae within the subfamily Aurantioideae of the Rutaceae family (Webber, 1967). The Aurantioideae is one of seven subfamilies of Rutaceae which consists of two tribes and 33 genera. Each of tribes Clauseneae and Citreae is composed of three subtribes. Clauseneae includes Micromelinae, Clauseninae and Merrillinae, and Citreae has Triphasiinae, Citrinae and Balsamocitrinae. The Citrinae is distinct from all the other subtribes in the subfamily by having pulp vesicles in the fruit. This subtribe contains three groups; primitive citrus fruit, near citrus fruit, and true citrus fruit trees. True citrus fruits have six genera: Clymenia, Eremocitrus, Microcitrus, Poncirus, Fortunella and Citrus (Swingle & Reece, 1967).

Peroxidase gene-based estimation of genetic relationships and population structure among Citrus spp. and their relatives

Many stress-related interactions such as pathogen infection, insect tolerance, salt tolerance, auxin degradation, cell wall lignification, tissue suberization, and plant senescence involve various isoforms of peroxidases. Peroxidase gene polymorphism (POGP) markers have been used to estimate diversity, relationships and population structure among 80 Citrus and their relatives in Aurantioideae by using unweighted pair group method arithmetic average (UPGMA) and bayesian substructuring analysis. Fourteen primers produced a total of 148 fragments and 147 of them were polymorphic. The UPGMA analysis demonstrated that the accessions had a similarity range from 0.27 to 0.98 and were distinguished. The results of this study were mostly consistent with previous reports of different marker systems, but few different findings were also detected. The subtribe Clauseninae (tribe Clauseneae) did not clearly separate from the subtribes of the tribe Citreae. Substructuring analysis indicated that there were six subpopulations among the accessions studied. This study revealed that the POGP markers can be utilized to estimate genetic diversity, relationships and population structure in Citrus and related species in the Aurantioideae subfamily.

Determination of genetic diversity among wild grown apricots from Sakit valley in Turkey using SRAP markers

Sequence-related amplified polymorphism (SRAP) marker was employed first time to analyze genetic diversity of 57 seed propagated early-maturated wild grown apricot genotypes sampled from different parts of Sakit valley in Mediterranean Region of Turkey. Of the total 19 primer combinations investigated, 16 could amplify clearly and consistently. They produced a total of 87 fragments, of which 56 (64.3%) were polymorphic bands. All bands obtained from Me3-Em2, Me2-Em10 and Me2-Em6 primers were polymorphic. The cluster analysis revealed that the 57 genotypes were grouped into three major clusters. The similarity ratio among genotypes was between 0.73 and 0.94. There were no identical genotypes. The study revealed that SRAP marker system was useful in identification and genetic diversity analysis of wild grown apricots.