Determination of the genome size and the number of markers for saturation of linkage maps of citrus
Roberto Pedroso de Oliveira; Carlos Ivan Aguilar-Vildoso and Marcos Antônio Machado
The objective of this study was to determine the size of the genome of citrus and correlate it with the number of markers necessary to saturate linkage maps. Linkage maps of ‘Pêra’ sweet orange (Citrus sinensis (L.) Osbeck) and ‘Cravo’ mandarin (C. reticulata Blanco) were constructed using 123 and 53 RAPD markers, respectively. The estimation of the genome size was conducted using regression models, the method of moments and Poisson probability. These approaches revealed a significant variation when estimating the genomes of ‘Pêra’ (612 to 1731 cM) and ‘Cravo’ (392 to 698 cM). The average number of markers necessary to saturate 99% of the genetic length determined for the genomes of ‘Pêra’ and ‘Cravo’ was 183 and 98, respectively. The linkage maps of these two varieties showed that the markers were distributed in clusters and this affected the accuracy of the estimates, especially of the ‘Cravo’ mandarin.