New alleles of maturity genes that influence soybean phenology

Soybean [Glycine max (L.) Merr.] is a photoperiod-sensitive legume native to Asia and a major global commodity crop. Adapting flowering time to match production environments can help maximize yield potential by extending the reproductive phase while optimizing the vegetative phase length. One major flowering gene, E1, and its two homologues, E1-like-A (E1LA) and E1-like-B (E1LB), have functionally characterized alleles, but use in breeding programs is limited to mainly e1-as for earlier flowering in northern latitudes (>36° N). Two new native alleles, e1:T110A and e1lb:S34R, are presented and characterized for their impact on days to flowering and maturity under maturity group III environments. Significant differences were observed between genotypes, and environment played a role in the lines under study. Lines with an e1-as background had the highest number of days in reproductive phase over our two environments; a line with allele e1lb:S34R (e1-as and E1LA) was inconsistent between years but had the longest reproductive phase in one environment. Overall, compared to soybean germplasm with functional E1, E1LA, and E1LB, lines with allele e1:T110A (E1LA and E1LB) were similar for days to flowering but matured, on average, 7 days earlier. Lines with previously characterized allele e1la:K82E (functional E1 and E1LB) had similar days to flowering and maturity as the new e1:T110A (E1LA and E1LB). The line with e1lb:S34R flowered and matured earlier than lines with functional E1LB (e1-as and E1LA). These new alleles highlight the natural diversity that could be utilized to produce cultivars well suited for a local environment.