selection in bean (phaseolus vulgaris l.) mutant populations for adaptative characters

The existence of variability is primary to success in plant breeding. The commercial bean cultivars have a narrow variability for adaptive traits. However, the use of mutagenic agents can increase the mutation frequency, allowing the development of genetic variability in useful traits. Thus, four bean genotypes were submitted to gamma rays from 60Co, at doses of 0, 100, 200 and 400 Gy in the 2006/07 crop season. In the following crop season (2007/08) the mutant populations, submitted to doses of 0, 100 and 200 Gy, were cultivated in a design of augmented blocks. The assessment of mutant and nonmutant families evidenced phenotypic divergence between families. From the Mahalanobis distance it was possible to distinguish four groups, indicating the possibility of selecting promising segregant families for stem diameter, plant height and height insertion of the first legume, without significantly changing grain-yield-related traits.