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Soybean (Glycine max) is a typical short‐day plant, but has been widely cultivated in high‐latitude long‐day (LD) regions because of the development of early‐maturing genotypes which are photoperiod‐insensitive. However, some early‐maturing varieties exhibit significant responses to maturity under different daylengths but not for flowering, depicting an evident photoperiodic after‐effect, a poorly understood mechanism. In this study, we investigated the postflowering responses of 11 early‐maturing soybean varieties to various preflowering photoperiodic treatments. We confirmed that preflowering SD conditions greatly promoted maturity and other postflowering developmental stages. Soybean homologs of FLOWERING LOCUS T (FT), including GmFT2a, GmFT3a, GmFT3b and GmFT5a, were highly accumulated in leaves under preflowering SD treatment. More importantly, they maintained a high expression level after flowering even under LD conditions. E1 RNAi and GmFT2a overexpression lines showed extremely early maturity regardless of preflowering SD and LD treatments due to constitutively high levels of floral‐promoting GmFT homolog expression throughout their life cycle. Collectively, our data indicate that high and stable expression of floral‐promoting GmFT homologs play key roles in the maintenance of photoperiodic induction to promote postflowering reproductive development, which confers early‐maturing varieties with appropriate vegetative growth and shortened reproductive growth periods for adaptation to high latitudes. Summary statement: The photoperiodic after‐effect of early‐maturing soybean varieties is caused by the maintenance of high‐level expression of floral‐promoting GmFTs. This phenomenon indicates that maturity exhibits a stronger photoperiod sensitivity than flowering time, which ensures an appropriate vegetative growth and shortened reproductive growth of early‐maturing soybean varieties to adapt to high latitudes with significant changes in photoperiods from long day to short day in the growing season. [ABSTRACT FROM AUTHOR]

Soil phosphorus (P) adsorption and desorption occur in an important endogenous cycle linked with soil fertility problems and relevant to the environmental risk assessment of P. In our study, the effect of long-term inorganic and organic fertilization on P adsorption and desorption characteristics in relation to changes in soil properties was evaluated by selecting three long-term experimental sites in southern China. The selected treatments at each site were CK (unfertilized), NPK (synthetic nitrogen, phosphorus and potassium) and NPKM (synthetic NPK plus manure). The adsorption and desorption characteristics of P were evaluated using Langmuir and Freundlich isotherms. The results showed that long-term application of NPK plus manure significantly increased soil organic carbon (SOC), total P and available P at all three sites compared with the NPK and CK treatments. All three treatments fit these equations well. The maximum adsorption capacity (Qm) of P increased with NPKM treatment, and the binding energy of P (K) and the maximum buffering capacity (MBC) showed increasing trends. NPKM showed the highest Qm (2346.13 mg kg-1) at the Jinxian site, followed by Nanchang (221.16 mg kg-1) and Ningxiang (2219.36 mg kg-1). Compared to CK and NPK, the NPKM treatment showed a higher MBC as 66.64, 46.93 and 44.39 L kg-1 at all three sites. The maximum desorption capacity (Dm) of P in soil was highest with the NPKM treatment (157.58, 166.76, 143.13 mg kg-1), showing a better ability to release P in soil. The correlation matrix showed a significant positive correlation of SOC, total and available P with Qm, Dm and MBC. In conclusion, it is suggested that manure addition is crucial to improve P utilization in red paddy soils within the recommended range to avoid the risk of environmental pollution.

Plants can sense the photoperiod to flower at the right time. As a sensitive short‐day crop, soybean (Glycine max) flowering varies greatly depending on photoperiods, affecting yields. Adaptive changes in soybeans rely on variable genetic loci such as E1 and FLOWERING LOCUS T orthologs. However, the precise coordination and control of these molecular components remain largely unknown. In this study, we demonstrate that GmFT5b functions as a crucial factor for soybean flowering. Overexpressed or mutated GmFT5b resulted in significantly early or later flowering, altering expression profiles for several downstream flowering‐related genes under a long‐day photoperiod. GmFT5b interacts with the transcription factor GmFDL15, suggesting transcriptional tuning of flowering time regulatory genes via the GmFT5b/GmFDL15 complex. Notably, GmFT5a partially compensated for GmFT5b function, as ft5a ft5b double mutants exhibited an enhanced late‐flowering phenotype. Association mapping revealed that GmFT5b was associated with flowering time, maturity, and geographical distribution of soybean accessions, all associated with the E1 locus. Therefore, GmFT5b is a valuable target for enhancing regional adaptability. Natural variants or multiple mutants in this region can be utilized to generate optimized soybean varieties with precise flowering times. Summary statement: Soybeans are sensitive to the photoperiod based on variable genetic loci, however, the coordination and control of these molecular components are unclear. In this work, we evaluate the molecular role and genetic variation of GmFT5b and identify its impact on flowering and regional adaptability in soybeans. [ABSTRACT FROM AUTHOR]

Seed size is a critical agronomic trait that influences the yield and appearance quality of soybeans, making it a primary breeding objective with significant economic value. While the molecular mechanisms that regulate soybean seed size remain largely unknown, several functional molecular targets have been applied in breeding to create larger grain size materials. In this study, we utilized the CRISPR/Cas9 system to induce the targeted mutagenesis of GmEOD1, which encodes the E3 ubiquitin ligase. The resulting homozygous soybean mutant of GmEOD1 exhibited larger seed size and 100-seed weight, with no significant change in the average seed weight per plant. The sum of crude protein and oil content increased significantly in mutants while fatty acid composition remained unchanged. We identified six haplotypes among 156 soybean cultivars, with Hap1 and Hap2 representing the majority of cultivars with relatively higher 100-seed weight, suggesting that sequence variations of GmEOD1 may correlate with seed weight. Transcriptomic analysis across five stages of seed development revealed that stages one–three mainly focused on cell cycle, growth, wall synthesis and modification, photosynthesis, and sugar metabolism; promoting cell growth, reproduction, and carbon accumulation; and providing key intermediates for substance synthesis. Stages four–five focused on polysaccharide catabolism, xylan metabolism, and nutrient pool activity, promoting the accumulation of dry matter, such as sugars, proteins, and lipids in seeds. Weighted gene co-expression network analysis (WGCNA) of modules related to seed size revealed 13 hub genes involved in seed development regulation. This study provides a valuable theoretical basis and excellent opportunities for genetic editing of germplasm cells with subsequent molecular soybean seed size breeding, facilitating easier seed selection to improve soybean quality. [ABSTRACT FROM AUTHOR]