DNA Amplified Fingerprinting, A Useful Tool for Determination of Genetic Origin and Diversity Analysis in Citrus

Abstract

We used three short repetitive nucleotide sequences [(GTG)5, (TCC)5, and (GACA)4] either as radiolabeled probes for hybridization with restricted citrus DNA or as single primers in polymerase chain reaction amplification experiments with total genomic DNA. We tested the ability of the sequences to discriminate between seedlings of zygotic or nucellar origin in the progeny of a Volkamer lemon (Citrus volkameriana Ten. & Pasq.) tree. The genetic variability within two species [Citrus sinensis (L.) Osbeck (sweet oranges) and Citrus reticulata Blanco and relatives (mandarins)] also was evaluated. DNA amplified fingerprinting with single primers was the more successful technique for discriminating between nucellar and zygotic seedlings. Although we were not able to distinguish among 10 cultivars of C. sinensis, all 10 C. reticulata cultivars tested were distinguishable. However, it still is difficult to identify the putative parents of a hybrid plant when the two parental genomes are closely related.