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In vitro genetic variability of sugarcane cultivars

Abstract:

Genotypic stability and uniformity of field plants from sugarcane cultivars grown in vitro (calli and cell suspensions) were evaluated by isoenzymatic peroxidase analysis after regeneration. Phenotypes of field plants exhibited uniformity within cultivars and differences among cultivars. Distribution of PRX isoenzymes was different in the constitution of the calli phenotypes, not only among cultivars but also within the same cultivar. Genotype PR980 showed a 60% heterogeneity coefficient, whereas the calli of cultivars PR62258, PR641791, PR692176, V64-10 and V71-51 showed identity coefficient of 100%. The isoenzymatic pattern of PRX for the phenotypes of cell suspensions was different among the four cultivars used, as well as within cultivars PR980 and V64-10, all of which showed heterogeneity coefficients of 50 and 22%, respectively. Nevertheless, the identity coefficient for regenerated plants of all genotypes was 100%. In sugarcane, the isoenzyme PRX1 is related to differentiated tissue, since it is present only in phenotypes from field and regenerated plants. PRX4 is induced in vitro conditions since it was observed only in callus tissue and cell suspensions. This study detected high uniformity and genetic stability within the regenerated plants in 100% of the sugarcane cultivars used.