Characterization of citrus germplasm including unknown variants by inter-simple sequence repeat (ISSR) markers

Abstract

Abstract Inter-simple sequence repeat (ISSR) markers were used to study phylogenetic relationships among 33 citrus genotypes including several undefined local or native varieties as well as some known varieties in the Fars Province of Iran. Based on 234 total ISSR fragments and 209 polymorphic fragments, a genotype similarity dendrogram was constructed using UPGMA cluster analysis. The 33 genotypes were classified into six major groups with, within-group similarity values of ≥0.65. Group 1 included Citrus sinensis and Citrus reticulata, group 2 common sour orange and ‘Peach’ sour orange, Group 3 ‘Bakraee’ and Volkameriana and three selections of sweet lime. ‘Bakraee’ is an undefined variety with morphological similarities to both sweet lime and mandarin. It is probably a hybrid between these two varieties. Group 4 included Lisbon lemon (Citrus limon) and two undefined selections ‘Rock lemon’ and ‘Pear-shaped lemon’. They might be mutant or hybrid lemons. Group 5 included a single genotype (D3) with little molecular similarity to other genotypes. Group 6 could be divided into two subgroups. One including citron (Citrus medica) and three local varieties of ‘Otroj’, ‘Bidkhoni’ from Darab and ‘Bidkhoni’ from Fassa. Based on their morphological and molecular similarities with citron, they are regarded as citron variants. The other subgroups of group 6 included Citrus aurantifolia, Citrus latifolia and 11 undefined genotypes with close morphological and molecular similarities to lime. The latter were considered as lime variants.