Assessment of genetic diversity of Tunisian orange, Citrus sinensis (L.) Osbeck using microsatellite (SSR) markers

Abstract

ABSTRACT. Citrus are one of the most cultivated crops in the world. Economically, they are very important fruit trees in Tunisia. Little is known about the genetic diversity of the Tunisian Citrus germplasm. Exploring this diversity is a prerequisite for the identification and characterization of the local germplasm to circumvent and controlling genetic erosion caused by biotic and abiotic stress to aid its conservation and use. In the present study, we explored the genetic diversity of 20 Tunisian orange cultivars [Citrus sinensis (L.) Osbeck] and established their relationships by using seven simple sequence repeat (SSR) loci. In total, 37 alleles and 44 genotypes were scored. The sizes of alleles ranged from 90 to 280 bp. The number of alleles per locus was from 4 to 7, with an average of 5.28. Polymorphic information content value changed from 0.599 to 0.769 with an average of 0.675. Analysis of the genotypes revealed a heterozygote deficiency across all the genotypes. The observed heterozygosity varied from 0 to 1 (average of 0.671). Cluster analysis showed that three groups could be distinguished and the polymorphism occurred independently of the geographical origin of the studied orange cultivars. The detected SSR genotypes allowed the establishment of an identification key with a discriminating power of 100%. Multivariate analysis and the neighbor-joining phylogenetic tree indicated a narrow genetic base for the orange cultivars. The usefulness of SSR markers for orange fingerprinting and evaluation of the genetic diversity in the Tunisian germplasm are discussed in this paper.

Acta Biologica Cracoviensia s. Botanica

“…Indeed, this orange was believed to be the same as Maltaise demi-sanguine cultivar, however, our results show that they are genetically different and they share only 7 alleles from a total of 18. Those results are in agreement with the findings of Mahjbi et al (2016) where two Sakasli and two 'Maltaise demi-sanguine' cultivars where found to be genetically different while analyzed by SSR markers. With the use of this set of markers, we could identify cases of synonymy and homonymy or misidentification.…”

Genetic relationships in a germplasm collection of Camellia japonica and Camellia oleifera using SSR analysis

“…Compared to dominant markers, SSR markers are co-dominant, highly reproducible, multi-allelic, and widely used in plant sciences (Hajmansoor et al, 2013) for germplasm characterization (Varshney et al, 2005;Peng et al, 2015;Queiroz et al, 2015), identification of genetic diversity (Gurcan et al, 2015;Jo et al, 2015;Mahjbi et al, 2016;Mornkham et al, 2016;Neiva et al, 2016), germplasm fingerprinting (Zhang et al, 2015), and integration of genetic linkage maps (Lai et al, 2013). For C. sinensis, SSR markers have been widely used to identify germplasm genetic diversity (Taniguchi et al, 2014), construction of linkage maps (Tan et al, 2013) and DNA-fingerprinting (Ujihara et al, 2009;Ma et al, 2010).…”

The genetic relationships of Indian jujube (Ziziphus mauritiana Lam.) cultivars using SSR markers

“…The obtained H E values of Indian jujube were closer to other tropical fruit trees such as mango cultivars [ 27 ], wax apple [ 26 ] and camu-camu [ 57 ], but much lower compared to Japanese plum cultivars [ 58 ], apple cultivars [ 59 ], Tunisian orange [ 60 ], Asian pear [ 61 ] and Chinese jujube [ 62 ]. These fruit cultivars have strong self-incompatibility [ 62 , 63 , 64 ] including Indian jujube [ 7 ].…”