Evaluation of spontaneous generation of allelic variation in soybean in response to sexual hybridization and stress

Espinosa, K., Boelter, J., Lolle, S., Hopkins, M., Goggi, S., Palmer, R. G. and Sandhu, D. 2015. Evaluation of spontaneous generation of allelic variation in soybean in response to sexual hybridization and stress. Can. J. Plant Sci. 95: 405-415. Intra-cultivar variation reported in pure lines of soybean has been hypothesized to result from genetic mechanisms contributing to de novo genetic variation. In this study we have detected allele switching by following segregation patterns of Aconitase-4 isozyme in sexual crosses and pure lines. In sexual crosses, one F2 plant showed a switch at the Aconitase-4 (Aco4) locus from the expected heterozygous genotype Aco4-ac to Aco4-ab. In the pure lines grown in a honeycomb planting design and treated with an accelerated aging test, multiple cases of allele switching were detected at the Aco4 locus. Both single and double switches were detected that were stable and heritable. These findings indicate that the generation of endogenous variation continues in pure lines ...