Genetic aspects of the time to flowering in natural variants of soybean

The parents and F-2 generations of a diallel cross with soybean (Glycine ma r (L.) Merrill) cultivar Parana and its natural variants Paranagoiana, SS-1 , and Pirapo 78 were studied with the objective of expanding the available knowledge on the genetic mechanisms of the time to flowering in soybean. Da ta were obtained under field conditions with photoperiod varying from 13 ho urs and 31 minutes, at planting date, to a maximum of 14 hours and 23 minut es, 59 days afterwards. No presence of epistasis was found in trait determi nation. The main component of genetic variation was additive. The results s howed that the delay in initial flowering was determined by recessive allel es. The alleles conditioning earliness were partially dominant. Broad and n arrow sense heritabilities were 99.68% and 89.96%, respectively. The geneti c information presented on the time to flowering, if evaluated jointly with the results obtained by other investigators, indicated that the type of in heritance is more dependent on the genotypes considered than on a specific photoperiodic band.