The effects and interaction of soybean maturity gene alleles controlling flowering time, maturity, and adaptation in tropical environments

Carrie Miranda,Andrew Scaboo,Elroy Cober,Kristin Bilyeu,Nicholas Denwar

doi:10.1186/s12870-020-2276-y

Carrie Miranda, Andrew Scaboo + Show 3 more

Open Access

https://doi.org/10.1186/s12870-020-2276-y

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Abstract

BackgroundSoybean is native to the temperate zones of East Asia. Poor yields of soybean in West African countries may be partially attributed to inadequate adaptation of soybean to tropical environments. Adaptation will require knowledge of the effects of allelic combinations of major maturity genes (E1, E2, and E3) and stem architecture. The long juvenile trait (J) influences soybean flowering time in short, ~ 12 h days, which characterize tropical latitudes. Soybean plant architecture includes determinate or indeterminate stem phenotypes controlled by the Dt1 gene. Understanding the influence of these genetic components on plant development and adaptation is key to optimize phenology and improve soybean yield potential in tropical environments.ResultsSoybean lines from five recombinant inbred populations were developed that varied in their combinations of targeted genes. The soybean lines were field tested in multiple environments and characterized for days to flowering (DTF), days to maturity (DTM), and plant height in locations throughout northern Ghana, and allelic combinations were determined for each line for associating genotype with phenotype. The results revealed significant differences based on genotype for DTF and DTM and allowed the comparison of different variant alleles of those genes. The mutant alleles of J and E1 had significant impact on DTF and DTM, and alleles of those genes interacted with each other for DTF but not DTM. The Dt1 gene significantly influenced plant height but not DTF or DTM.ConclusionsThis research identified major and minor effect alleles of soybean genes that can be combined to control DTF, DTM, and plant height in short day tropical environments in Ghana. These phenotypes contribute to adaptation to a low latitude environment that can be optimized in a soybean breeding program with targeted selection of desired allele combinations. The knowledge of the genetic control of these traits will enhance molecular breeding to produce optimally adapted soybean varieties targeted to tropical environments.

Highlights

Soybean is native to the temperate zones of East Asia
Utilizing seven parents with contrasting alleles of the major soybean maturity genes, the plant architecture gene for stem termination, and the long juvenile trait, five recombinant inbred line (RIL) populations were developed to determine the effect of those allele combinations on phenology and agronomic phenotypes in tropical field environments of northern Ghana (Table 1 and Table 2, Additional file 1)
The F2 plants in the Jake-15, Jake-Pa, and X97–15 populations were evaluated for the long juvenile trait in a tropical field environment at a commercial winter nursery in Costa Rica at ~11o N latitude, and about 25% of the Jake-15 and Jake-Pa plants that exhibited long juvenile characteristics were selected for advancement

Summary

Introduction

Soybean is native to the temperate zones of East Asia. Poor yields of soybean in West African countries may be partially attributed to inadequate adaptation of soybean to tropical environments. When soybean is grown in a 12 h or less day length, it receives the cue to start flowering immediately upon emergence, making it difficult to adapt to latitudes below 20° [15,16,17,18,19]. This early flowering results in a short stature plant that matures prematurely and leads to reduced yields [20]

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