Inheritance was studied in natural variants of the soybean cultivar Parana,
developed under photoperiodic conditions ranging from 13 h 31 min day ligh
t, at sowing, to 14 h 23 min, 59 days afterwards. Results indicated that ea
rly flowering and maturity are controlled by a single dominant gene. Natura
l mutations that originated cultivars Paranagolana and SS-1 occurred at the
same locus of cultivar Parana. It was not possible to determine if the rec
essive alleles of these mutant cultivars are different. The designation E-6
was proposed for the alleles determining earliness in cultivar Parana, and
e(6) for the gene determining late flowering and maturity in cultivars Par
anagoiana and SS-1, until the individuality of the alleles of Paranagoiana
and SS-1 is confirmed.