Isozyme variability analysis in plant introductions and cultivars of sunflower

The amount of available genotypes of sunflower (Helianthus annuus L.) to th e agriculturists is minimum and the knowledge concerning genotypes from oth er countries, which could be used in this crop plant breeding is scarcely k nown. This work had the purpose of assessing the genetic variability of 31 accessions and of five cultivars to the isoenzymatic systems phosphoglucomu tase (PGM), phosphogluconate dehydrogenase (PDG), glucose-6-phosphate isome rase (PGI) and carboxylesterase (EST). The starch or penetrose gel electrop horesis technique was applied aiming the fractionation of the PGM, PGI and PGD isoenzymes, and the EST isoelectric focusing. Six loci and 14 alleles t o these four systems were detected. Allelic variation were observed on the Pgi2, Pgm1, Pgd2 loci, two alleles each, and to Est1, which displayed six a lleles. The goodness of fit tests for the Hardy-Weinberg and Wright equilib rium models indicated that ten accession showed a significant excess of sel fing.