Genetic diversity among hybrids of sweet orange and 'Murcott' tangor evaluated by fAFLP and RAPD markers

The objective of this work was to evaluate the genetic diversity in a population of 148 hybrids of 'Murcott' tangor (Citrus reticulata Blanco x C. sinensis L. Osbeck) and 'Pêra' sweet orange (C. sinensis L. Osbeck), obtained by controlled polination, using fAFLP and RAPD markers. Polymorphic markers (416 fAFLP and 33 RAPD markers) were used to evaluate genetic similarity among the hybrids, calculated by the coefficient of Jaccard, using the UPGMA method. The consistency of each group was determined by software BOOD. There was high genetic similarity within the parents. 'Pêra' sweet orange had a higher number of loci in heterozygosis (132) compared to 'Murcott' tangor (105), supporting the theory of hybrid origin for sweet oranges. Two distinct groups of plants were observed: one group had 80% of the hybrids that displayed higher genetic similarity with 'Pêra' sweet orange. The bootstrap analysis did not show consistence between the groups. The fAFLP markers are more efficient to obtain polymorphism than RAPDs and are more suitable to select hybrids closer to the parents.