Molecular characterization of a novel mutation in the flowering gene induced by gamma irradiation in soybean.

Soybean is a typical short-day (SD) plant. It undergoes reproductive growth only when the day length becomes shorter than a critical length. Fourteen major genes/loci affecting soybean flowering and maturity period have been mapped to date. These are and on chr6, , , , , and on chr4, on chr10, on chr19, on chr20, on chr6, 0 on chr8, on chr19, and on chr14. The functional allele of all these genes, except , , , and , delay flowering, while the non-functional counterpart accelerates flowering and maturity. The contribution of the gene in delaying flowering is highest. Four non-functional/dysfunctional allelic variants of the gene are already known, which accelerates the flowering by 20-25 days and are being used in development of early maturing soybean varieties in many parts of the world. In this study, seeds of the late maturing Indian variety NRC 37 were irradiated with gamma rays to develop an early maturing variety. One early maturing variant was obtained. Molecular characterization of the gene responsible for early flowering proved it to be a non-functional variant of the gene with major deletion.