<b>Isozyme diversity in RB (Republic of Brazil) sugarcane (<em>Saccharum spp</em>) varieties</b> - DOI: 10.4025/actascibiolsci.v25i1.2094

Abstract

Isozyme electrophoresis was used as a method in the identification of biochemical markers for genotype discrimination and for genetic diversity determination in five varieties of sugarcane, Saccharum spp. (Poaceae) cultivated in the northern Paraná, Southern Brazil. The five RB (Republic of Brazil) varieties represent improved genetic material, useful for sugar and alcohol production. SOD isozyme pattern can be used as biochemical markers to discriminate the sugarcane RB (72454, 835089, 845257, 855156 and 855536) varieties. The proportion of polymorphic loci was 25% for the RB835089, RB855156, RB855536, and RB72454 varieties and 18.8% for the RB845257 variety. Genetic diversity showed high I values; however, the levels of intervariety genetic divergence demonstrated by the F-statistic values indicated a deficit of heterozygotes for the cPer-2 locus (F_(IS) = 0.743). The standardized variance in allele frequency among the five RB varieties was F_(ST) = 0.434 for the cPer-2 locus, and the value calculated for the mean standardized variance in allele frequency among the five RB varieties for the 4 loci was F_(ST) = 0.182. Thus, the directional selection process for the development of the sugarcane RB varieties seems to have played a major role in determining selection of homozygous plants