The use of random amplified polymorphic DNA to evaluate the genetic variability of Ponkan mandarin (Citrus reticulata Blanco) accessions

Abstract

RAPD analysis of 19 Ponkan mandarin accessions was performed using 25 random primers. Of 112 amplification products selected, only 32 were polymorphic across five accessions. The absence of genetic variability among the other 14 accessions suggested that they were either clonal propagations with different local names, or that they had undetectable genetic variability, such as point mutations which cannot be detected by RAPD.<br>Amplificações RAPD foram desenvolvidas utilizando-se 25 "primers" de seqüência aleatória e 19 acessos de tangerinas pertencentes ao grupo das Ponkan. Dos 112 produtos de amplificação selecionados somente 32 foram polimórficos, sendo este polimorfismo restrito somente a 5 acessos. Nos 14 acessos restantes não pôde ser detectada qualquer variabilidade genética, sugerindo que estes podem ser propagação clonal da tangerina `Ponkan', tendo os mesmos adquirido diferentes nomes regionais ao longo do tempo. Ou, por outro lado, a técnica RAPD utilizada pode não ter detectado qualquer mutação de ponto que tenha ocorrido nestes materiais ao longo do tempo

Assessment of the genetic variability amongst mandarin (Citrus reticulata Blanco) accessions in Bhutan using AFLP markers

“…The ability of AFLP to separate closely related accessions supports the findings of Colletta Filho et al . [ 6 ]. Bhutanese mandarin accessions, all supposedly representing a single variety were well segregated by the technique.…”

“…Mandarin ( Citrus reticulata Blanco) is believed to be one of the three true Citrus species [ 2 ]. It is also one of the most diverse group of citrus [ 2 - 6 ]; consisting of numerous intergeneric species and interspecific hybrids [ 7 , 8 ], and as a result is viewed as one of the most challenging with respect to classification and genetic improvement [ 8 ]. This genetic variability has been variously attributed to a high proportion of zygotic twins [ 9 ], intergeneric cross compatibility, high heterozygosity, nucellar embryony and a long history of cultivation and wide distribution around the world.…”