Comparison of the phenotypic variability in F2 and M2 populations of sorghum attained by hybridization and mutagenesis respectively

In the last twenty years, plant breeding programs for sorghum in Mexico had been supported mainly in the introduction of lines or parental population, instead of generate its own genetic sources. The creation of one's own germoplasma and the resultant enlargement of genetic variability can do in several manners. Hybridization methodology has been used for this purpose, taking advantage of uneven hereditary constitution of individuals to produce segregate genotypes; therefore, induce mutations technology where sudden changes are made useful and give origin to a heritable of the genotype has used in less degree, may be for the absence of validation studies of this technique for the obtention of superior genotypes. At all events anyway, few are the studies where both methodologies as variability sources are compared. In this work, magnitude and direction of phenotypic variability for agronomical characters of sorghum are compared, in populations F2 and M2 of hybridization and mutagenesis methods respectively, in comparison with no hybrid or no irradiated witnesses between them, under the hypothesis that characteristics of phenotypic variability depends on methodology used to obtain it. (Author). 16 refs, 4 tabs