Genetic reticulation and interrelationships amongcitrullusspecies as revealed by joint analysis of shared AFLPs and species-specific SSR alleles

Abstract

Thirty-one accessions of Citrullus spp. belonging to Citrullus lanatus var. lanatus, C. lanatus var. citroides and Citrullus colocynthis were subjected to phylogenetic analysis using combined datasets of amplified fragment length polymorphisms (AFLPs) and simple sequence repeats (SSRs). Tree topologies inferred by neighbour-joining analysis have resolved the phylogenic relationships among the species with special reference to established taxonomic classification. In this study, we have clearly resolved species boundaries of various taxa of citroides, lanatus and colocynthis into three well-supported clusters. Clustering pattern of principal component analysis with the shared polymorphisms using the subsets of data between any two taxon combinations helped to elucidate the introgression and interrelationships among the species. We report two major groups of C. lanatus taxa, one of which has undergone wide introgressions with the taxa of C. lanatus var. citroides and C. colocynthis. In this paper, we identified 583 AFLP bands that are polymorphic within the var. lanatus of C. lanatus, which is the largest set ever reported. The species-specific diagnostic SSRs and polymorphic AFLPs that are informative within and between the taxa reported in this paper would be immensely useful for future studies of these economically important genera.

Mapping of the Egusi Seed Trait Locus (eg) and Quantitative Trait Loci Associated with Seed Oil Percentage in Watermelon

“…egusi (Fursa, 1972;Jeffrey, 2001) and have sometimes been misclassified as C. colocynthis (Gusmini et al, 2004;Jarret et al, 1997;Robinson and Decker-Walters, 1997;Wehner, 2008). However, chloroplast (Dane and Lang, 2004;Dane and Liu, 2007) and nuclear (Che et al, 2003;Jarret et al, 1997;Nimmakayala et al, 2010) genetic studies do not support the subspecies classification and groups egusi types with cultivated watermelon (Citrullus lanatus var. lanatus).…”

Assessment of the genetic diversity of dessert watermelon (Citrullus lanatus var. lanatus) landrace collections of South Africa using SSR markers

“…However, this was lower than 133, 101 and 795 alleles detected by Zhang et al (2016), Wang et al (2015) and Reddy et al (2015) among watermelon accessions, respectively. Nimmakayala et al (2009) reported a total of 169 alleles amplified in watermelon accessions. In the current study the number of alleles per locus ranged from 2 to 19, with a mean of 9.4.…”

Genetic diversity within Turkish watermelon [Citrullus lanatus (Thunb.)Matsumura & Nakai] accessions revealed by SSR and SRAP markers

“…Guerra-Sanz (2002) reported 1-8 alleles in C. lanatus genotypes and varieties, 0-2 alleles in C. colocynthis genotypes, and 0-4 alleles in hybrids by using 18 SSR markers. In another study, Nimmakayala et al (2010) estimated the phylogenetic relations of 31 accessions of C. lanatus var. lanatus, C. lanatus var.…”