Grain Yield Of Soybean Research Articles

COL3a simultaneously regulates flowering and branching to improve grain yield in soybean.

COL3a simultaneously regulates flowering and branching to improve grain yield in soybean.

Effects of Biochar and Bradyrhizobium Inoculation on Nodulation, Growth, and Grain Yield of Soybean in the Guinea Savanna Agroecological Zone of Ghana

ABSTRACT Soybeans are a vital crop globally, significantly contributing to food security, soil fertility, and economic development. However, soil conditions can constrain their productivity, including nutrient deficiencies and acidity. This study explores the combined effects of biochar (BC) and Rhizobium inoculation (RI) on soybean growth, nodulation, and yield. The experiment was conducted over two growing seasons and employed a split-plot design with five BC application rates (0, 2, 4, 6, and 8 t ha− 1) and two RI levels (uninoculated and inoculated) across four replications. The results demonstrated that the integration of BC and RI significantly improved various growth parameters, including nodulation, biomass accumulation, pod number, and grain yield. The highest grain yield was observed at 8 t ha−1 BC with RI, yielding 3394 kg ha−1 in 2021 and 2542 kg ha−1 in 2022. This was identical to the yield attained with the 6 t ha−1 BC rate paired with RI in both years. The inoculated control treatment consistently demonstrated the lowest grain yield. Additionally, it showed a significant (p < .05) impact on the weight of one hundred seeds. The study also revealed significant and consistent relationships among soybeans’ growth and yield features. In conclusion, the findings suggest that the combined application of BC and RI has a positive impact on soybean yield and its key components.

Changes in Soil Physical Properties and Soybean Productivity under Preparatory Tillage Systems in Virgin Vertisols of Central India

Preparatory tillage, undoubtedly, is one of the most crucial practices that alter soil physical attributes and also affect crop growth and yield. In this sense, this experiment was designed to evaluate the effect of various preparatory tillage systems on soil physical properties and soybean productivity thereby find out a suitable tillage combination for vertisol of Vidarbha region of central India. The experiment was laid out in a randomized block design with eight tillage treatments and three replicates. Experimental results revealed that soil physical properties and productivity of soybean differed significantly under different preparatory tillage system and zero tillage. Further data revealed that conventional tillage treatment T8 (1ploughing + 2 tyne harrow + blade harrow) and T7 (1 Ploughing + 1 Tyne Harrow + 1 Rotavator) significantly improved the soil physical properties (infiltration rate, bulk density, porosity, soil moisture content) and grain yield (2378 and 2268 kg ha-1, respectively). Moreover zero tillage treatment T1 and shallow tillage treatments (1Blade Harrow + 1Rotavator and 1Tyne Harrow + 1 Rotavator) did not show any significant improvement in soil physical properties and grain yield of soybean.

A new phosphorus fertilizer blend enhances grain legume yield and profitability in northern part of Ghana

Low concentrations of phosphorus limit grain legumes’ yield in the northern part of Ghana. Smallholder farmers could benefit from P-fertilizer blends to improve yield. This study evaluated the responses of soybean, cowpea and groundnut to P-fertilizer blends and their profitability in researcher-managed and farmer-managed trials in Northern, Upper West, and Upper East regions. The experiment was set up in a cross-factorial arranged in randomized complete block design with four replications. The treatments were two types of P-fertilizer blends (triple superphosphate and new yaraLegume applied at 30 kg P ha−1), a control and three varieties each of soybean (TGX 1835-10E, TGX 1789-8E and TGX 1834-5E), cowpea (Padituya, Wang-Kae and Kirkhouse), and groundnut (Samnut 23, Samnut 22 and Yenyawwaso). P-fertilizer blends increased grain yield of grain legumes in researcher-managed trials. In the researcher-managed trials, P-fertilizer blends doubled the nodulation of soybean varieties but did not influence the nodulation of cowpea and groundnut. P-fertilizer blends increased P-agronomic efficiency over control; however, the different P-fertilizer blends had similar P-use efficiencies. In farmer-managed trials, only the yield of groundnuts varied with the different P-fertilizer blends in the Upper West region, suggesting that P utilization may be location-specific for groundnuts. P-fertilizer blends increased the grain yield of soybean and cowpea varieties in the Northern and Upper West regions but not the Upper East region. The interaction between soybean and cowpea varieties and P-fertilizer blends was not significant. P-fertilizer blends recorded a higher value cost ratios (VCRs) that can offset uncertainties in price fluctuations. The high VCRs indicated that P-fertilizer blends were profitable and could be used to improve the livelihoods of smallholder grain legume farmers. The study demonstrated that grain legumes responded to P-fertilizer blends and are profitable. However, the non-responsive nature of the Upper East soils needs to be investigated to make P-fertilizer blends profitable in the region.

Genome-wide association studies reveal novel QTLs for agronomic traits in soybean.

Soybean, as a globally significant crop, has garnered substantial attention due to its agricultural importance. The utilization of molecular approaches to enhance grain yield in soybean has gained popularity. In this study, we conducted a genome-wide association study (GWAS) using 156 Chinese soybean accessions over a two-year period. We employed the general linear model (GLM) and the mixed linear model (MLM) to analyze three agronomic traits: pod number, grain number, and grain weight. Our findings revealed significant associations between qgPNpP-98, qgGNpP-89 and qgHGW-85 QTLs and pod number, grain number, and grain weight, respectively. These QTLs were identified on chromosome 16, a region spanning 413171bp exhibited associations with all three traits. These QTL markers identified in this study hold potential for improving yield and agronomic traits through marker-assisted selection and genomic selection in breeding programs.

Intraspecific competition in row spacings in soybean

The aim of this study is to assess the impact of various row spacings on the morphology, components of grain yield, and overall grain yield of soybean. The experiments were conducted over two planting seasons (2014/2015 and 2015/2016) using two planting dates (November and December) and two cultivars, FPS Urano RR and BMX Tornado RR. The row spacings tested were: 45 cm (wide row), 45 &amp;times; 45 cm (cross row), 22.5 &amp;times; 45 cm (twin row), and 22.5 cm (narrow row). Measurements included leaf area index and sunlight interception at R2 stage, as well as grain yield components and overall grain yield. Narrow rows, in addition to achieving canopy closure, also demonstrated enhanced sunlight interception at the R2 stage. However, the positive effect of increased sunlight interception on grain yield was only significant for the December planting date, with no notable difference observed for the November planting date. These findings imply that while narrow rows may offer advantages, particularly in later planting dates, their implementation should be carefully considered and may not consistently lead to increased grain yield, reinforcing the continued preference for conventional row spacing.

Effect of combined use of supplementary irrigation, manure and P fertilization on grain yield and profitability of soybean in northern Nigeria

Declining soil fertility particularly phosphorus deficiency, low organic carbon, moisture stress and high cost of input are factors limiting soybean yield in the Nigeria savanna. Supplementary irrigation, nutrient application and inoculation with Bradyrhizobium could increase the grain yield of soybean. We evaluated the effects of Rhizobia inoculant, phosphorus fertilization, manure, and supplementary irrigation on the nodulation and productivity of a tropical soybean variety in two locations in northern Nigeria in the 2017 and 2018 cropping seasons. The treatments consisted of five input bundles: Supplementary irrigation +17.5 kg P ha−1 + 4 t ha−1 poultry manure + nodumax inoculant (S + P + M + I); 17.5 kg P ha−1 + 4 t ha−1 poultry manure + nodumax inoculant (P + M + I); 17.5 kg P ha−1 + nodumax inoculant (P + I); 17.5 kg PP ha−1 (P); and nodumax inoculant (I). Economic analysis was done to determine the benefit-cost ratio (BCR) for each input bundle. In Kano, the input bundle S + P + M + I produced mean number of nodules that were 38, 102, 200 and 352% higher than that of input bundles P + M + I, P + I, P and I, respectively. At Lere, the application of input bundle S + P + M + I increased mean number of nodules by 33, 81, 93 and 182% over that of input bundles P + M + I, P + I, P and I, respectively. Mean grain yield in Kano was greater for input bundle S + P + M + I over P + M + I, P + I, P and I bundles by 31, 50, 64 and 223%, respectively. In Lere, grain yield for input bundle S + P + M + I was higher than that of input bundles P + M + I, P + I, P and I only, by 27, 47, 41 and 184% respectively. The input bundle P + M + I produced the highest BCR (1.4) in Kano and application only of P produced the highest BCR (1.3) in Lere. Supplementary irrigation was not found to be profitable due to the high cost of supplementary irrigation.The application of P with or without manure/inoculant is recommeded for profitable soybean production in the savannas of Nigeria.

Soil Characteristics, Growth, Yield, Mineral Composition and Proximate Content of Soybeans Under Various Tillage Techniques

Different tillage methods can have varying effects on soil properties and crop quality. Therefore, field experiments were conducted at the Teaching and Research Farm of Landmark University, located in Omu‐Aran, Kwara State. The objectives were to investigate the impacts of various tillage methods on soil characteristics and the growth, yield, mineral and proximate content of soybean (Glycine max (L.) Merr.). Based on these objectives, it was hypothesized that soil properties, growth, yield, mineral and proximate contents of soybean would react differently to different tillage methods. Consequently, experiments were conducted to validate this hypothesis. The treatments were four tillage methods: manual clearing (MC), ploughing (P), ploughing plus harrowing (P + H) and manual ridging (MR), replicated three times in a randomized complete block design. Data on the initial soil properties (bulk density, particle size, pH, organic matter, N, P, K, Ca and Mg), along with the chemical properties of the soil on a per‐plot basis at the end of the experiment, were collected. Additionally, data on soil bulk density, porosity, moisture content and temperature were collected during the vegetative growth of the soybean. Soybean plant height and the number of branches were recorded at the midflowering stage, while grain yield and the number of pods were recorded at harvest. Soybean seeds were later analysed for their mineral and proximate contents using standard methods. P + H resulted in lower soil bulk density than other tillage methods and led to higher growth, yield, proximate and mineral contents of soybean. In MC, bulk density, soil moisture content, soil organic matter, N, P, K, Ca and Mg were significantly higher and temperature lower than in other tillage methods; yet, these advantages did not translate into increased yield and quality due to the higher bulk density. The growth, yield and quality of soybean were significantly influenced by soil bulk density rather than by soil chemical properties. Using the mean of the two sites, relative to MC, P and MR, P + H increased the grain yield of soybean by 41.3%, 24.4% and 13.7%, respectively. These findings underscore the importance of appropriate tillage practices for successful soybean cultivation in similar agroecological zones. For small‐scale operations, MR is suggested, while P + H is recommended for large‐scale soybean production in the studied area. Future studies could include additional variables, such as economic analysis, long‐term soil health impacts or the effects of tillage methods under varying climate conditions.

Effect of a Bacillus velezensis and Lysinibacillus fusiformis-based biofertilizer on phosphorus acquisition and grain yield of soybean.

Phosphate-solubilizing bacteria that function through acidification (organic acid synthesis) or mineralization (production of enzymes such as phytase and phosphatases) have been explored as a biotechnological alternative to enhance plant access to phosphorus (P) retained in organic and inorganic forms in agricultural soils. This study tested the hypothesis that applying a biofertilizer composed of a recognized phosphate-solubilizing bacterium (Bacillus velezensis - endophytic strain BVPS01) and an underexplored plant growth-promoting bacterium (Lysinibacillus fusiformis - endophytic strain BVPS02) would improve the growth and grain yield of Glycine max L. plants. Initial in vitro tests assessed the functional traits of these bacteria, and a mix of strains BVPS01 and BVPS02 was produced and tested under field conditions to evaluate its agronomic efficiency. The results confirmed the hypothesis that the tested biofertilizer enhances the agronomic performance of G. max plants in the field. The B. velezensis strain (BVPS01) was found to be more effective than the L. fusiformis strain (BVPS02) in solubilizing phosphates via the phosphatase enzyme production pathway, indicated by the expression of the phoC and phoD genes. In contrast, L. fusiformis was more effective in solubilizing phosphates through organic acid and phytase-related pathways, in addition to synthesizing indole-3-acetic acid and increasing the mitotic index in the root meristem of G. max plants. These strains exhibited biological compatibility, and the formulated product based on these rhizobacteria enhanced root development and increased the number of nodules and flowers, positively affecting 1000-grain weight, grain yield, and grain P content. Thus, the tested biofertilizer demonstrated potential to improve root growth and increase both the yield and quality of soybean crops, making it a sustainable and low-cost strategy.

Lithothamnium Effects on Soil Attributes, Phosphorus Utilization Efficiency, and Grain Yield of Soybeans, Corn, and Common Bean

Lithothamnium Effects on Soil Attributes, Phosphorus Utilization Efficiency, and Grain Yield of Soybeans, Corn, and Common Bean

Effects of agricultural management and of climate change on N2O emissions in an area of the Brazilian Cerrado: Measurements and simulations using the STICS soil-crop model

Soil-plant simulation models have been ever more used as predictive tools to evaluate productivity and environmental impacts of agriculture practices. The aims of this work were to evaluate the STICS model’s capacity of simulate the emissions of nitrous oxide (N2O) under different management systems. And, to predict, by applying the calibrated and validated STICS model, the N2O emissions, under different management systems, in the edaphoclimatic conditions of the Brazilian Cerrado. The study was conducted in a long-term experiment at Embrapa Cerrados, located in Planaltina/DF, Brazil. The experiment started in 1995. The following land use systems were evaluated: CT - conventional tillage with disc harrow, and biannual grass/legume rotation; NT1 - No-tillage, with biannual crop rotation – soybean/sorghum; NT2 - No-tillage, with biannual crop rotation – maize/pigeon pea.Closed static chambers and gas sample analysis by gas chromatography were used to measure N2O fluxes. The model was calibrated with the data measured in the CT and NT1 treatments. The attributes used in the calibration were: growth, development and yield of crops and N2O fluxes. To test the model, data from the NT2 treatment was used. Data for all treatments were collected at the same time. After calibration and validation, the STICS model was used to predict the effects of soil management systems, conventional (CT) and no-tillage (NT) on greenhouse gas emissions and on grain and biomass crops production. The simulation was made for the period from 2021 to 2070. The STICS model performed well at simulation of the following parameters: N2O emissions, soil water dynamics, soil temperature; and leaf area, aerial biomass and grain yield of soybean and maize. The performance of the model was good for the conventional soil management system as well as in the no-tillage system. Based on the predicted increase in temperature for the period 2021–2070, we can conclude from the data generated through the STICS model that there is strong evidence that grain yield and total aerial biomass of plants will decrease. The data show that there is a rising tendency in N2O emissions over the simulated period. This is expected to occur for the two soil management systems studied (NT and CT). We believe this increase in emissions along the years is related to temperature increase and to the reduction of crop cycle.

Management of leaf eating caterpillars through intercropping with Suva, Anethum graveolens in soybean

Defoliators are common insect pests of soybean and often cause economic losses. Insecticides are the first option that farmers choose to minimize the damage caused by the defoliators, and the result is not only the emergence of resistance to insecticides in the pests but also environmental pollution. A field experiment carried out at the UAS, Dharwad, India, during Kharif 2021 tested different combinations of Soybean+suva intercrop for their ability to reduce the damage caused by defoliators to soybean leaves and the effect on grain yield of soybean. Among these, Soybean + Suva (3 soybean: 2 suva: 3 soybean rows combination) was effective in reducing larval population.

Correlation and path analysis in black and brown seeded soybean [Glycine max (L.) Merr.] genotypes at Melko and Modio, South-Western Ethiopia

Sixty-four soybean genotypes were evaluated to study the association among yield and related traits and determine the directions of association. The field experiment was conducted during the main cropping season in 2019 at Jimma and Bonga Southwestern Ethiopia. The experiment was laid with a simple lattice design with two replications. Data were collected on quantitative traits. Analysis of variance showed significant to highly significant differences among genotypes for all of the studied traits. Correlation analysis exhibited that grain yield was positively and significantly associated with harvest index and the number of pods per plant. Harvest index exerted the maximum positive direct effect on grain yield, followed by pod per plant, seed yield per plant at a genotypic level, and these traits could be used for selection to improve grain yield in soybean. Int. J. Agril. Res. Innov. Tech. 13(1): 67-71, June 2023

Mixture of winter cover crops improves soil physical properties under no-tillage system in a subtropical environment

The monocrop of winter cover crops is a common practice under no-tillage system (NTS) in subtropical environment but increase diversity of cover crop species can be an alternative to improve soil physical quality, with positive effects on crop production. This study evaluated whether using a greater diversity of cover crop species affects soil physical properties, as well as grain yield of soybean (Glycine max L.) and common bean (Phaseolus vulgaris L.) under NTS in three growing seasons. The experimental design was in randomized blocks with four replications. The treatments were monocrop of black oat (Avena strigosa Schreb.); intercropping of black oat and turnip (Brassica napus L.); and a mixture of black oat, turnip, white oat (Avena sativa L.), rye (Secale cereale L.), white lupine (Lupinus albus L.), and common vetch (Vicia sativa L.). Cover crop biomass yield, soil physical properties, and grain yield of summer crops were evaluated. Using a mixture of cover crops improved soil physical properties by decreasing soil bulk density up to 5 %, increasing soil air-filled porosity at –100 hPa (0.0–0.2 m) up to 27 % and saturated hydraulic conductivity (0.0–0.2 m) up to 300 %. Common bean grain yield and 1000-grain weight in succession to the mixture of cover crops increased by 15 % and 4 %, respectively. Soybean yield components were not affected by treatments. The increased diversity of winter cover crops improved soil physical properties in relation to monocrop in NTS, as well as improved crop yield of common bean, which is a shallower root growth specie, more sensitive to soil constraints.

BIOAGENTS AND MIX OF COVER PLANTS AFFECTING SOYBEAN

The search for cultivation practices that provide productive, social and environmental benefits to the agroecosystem is of great importance for the sustainable intensification of agriculture. The objective of this study was to determine the effect of multifunctional microorganisms (MM) and mix of cover crops on gas exchange, production components and grain yield of soybean. In the field experiment, conducted by two growing seasons, the experimental design of randomized blocks in factorial scheme 8x2 was used, with four replications. The treatments were composed by the combination of eight vegetal cover and the use or not of MM. The vegetal cover were composed of: 1. Fallow, 2. Corn, 3. Mix 1 (white lupine, buckwheat, white oats, black oats, Crotalaria ochroleuca, C. juncea, turnip, coracana grass, white lupine), 4. Mix 2 (millet, C. ochroleuca, black oats, white oats, buckwheat, coracana grass), 5. Mix 3 (Millet, C. ochroleuca, black oats, white oats, buckwheat, coracana grass), 6. Mix 4 (C. spectabilis, buckwheat, millet and C. breviflora), 7. Mix 5 (oats, buckwheat, millet, piatã grass and C. Ocholeuca); and 8. Mix 6. (black oats, turnip forage, white lupine, coracana grass, buckwheat). The MM consortium used was Serratia marcenses (BRM 32114) + Bacillus sp. (BRM 63573). Soybean plants coinoculated with (BRM 32114) + (BRM 63573) showed an increase in photosynthetic rate (16.65%), stomatal conductance (37.50%), internal CO2 concentration (10%), number of pods per plant (15%), mass of 100 grains (4.04%) and grain yield (14.83%). However, no differences were observed in soybean plants grown in succession to the mix of cover crops, except for the number of grains per pod. Therefore, in this study, the highlight was the consortium of multifunctional microorganisms, technology considered strategic for the sustainable intensification of agriculture.

2-Oxoglutarate contributes to the effect of foliar nitrogen on enhancing drought tolerance during flowering and grain yield of soybean

Drought severely affects the growth and yield of soybean plants especially during the flowering period. To investigate the effect of 2-oxoglutarate (2OG) in combination with foliar nitrogen (N) at flowering stage on drought resistance and seed yield of soybean under drought stress. This experiment was conducted in 2021 and 2022 on drought-resistant variety (Hefeng 50) and drought-sensitive variety (Hefeng 43) soybean plants treated with foliar N (DS + N) and 2-oxoglutarate (DS + 2OG) at flowering stage under drought stress. The results showed that drought stress at flowering stage significantly increased leaf malonaldehyde (MDA) content and reduced soybean yield per plant. However, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities were significantly increased by foliar N treatment, and 2-oxoglutarate synergistically with foliar N treatment (DS + N + 2OG) was more beneficial to plant photosynthesis. 2-oxoglutarate significantly enhanced plant N content, glutamine synthetase (GS) and glutamate synthase (GOGAT) activity. Furthermore, 2-oxoglutarate increased the accumulation of proline and soluble sugars under drought stress. Under drought stress, soybean seed yield was increased by DS + N + 2OG treatment by 16.48–17.10% and 14.96–18.84% in 2021 and 2022, respectively. Thus, the combination of foliar N and 2-oxoglutarate better mitigated the adverse effects of drought stress and could better compensate for the yield loss of soybean under drought stress.

Effects of Nitrogen Supply on Dry Matter Accumulation, Water-Nitrogen Use Efficiency and Grain Yield of Soybean (Glycine max L.) under Different Mulching Methods

In dryland agriculture, mulching methods and nitrogen application have been extensively adopted to improve water and nitrogen use efficiency and increase crop yield. However, there has been a scarcity of research on the combined effects of mulching types and nitrogen application on the growth and yield of soybean (Glycine max L.). In the present study, four nitrogen levels (N0: 0 kg N ha−1, N1: 60 kg N ha−1, N2: 120 kg N ha−1, N3: 180 kg N ha−1) and four mulching methods (NM: no mulching, SM: straw mulching, FM: film mulching, SFM: straw and film mulching) were set so as to evaluate the effects of mulching methods and nitrogen application on dry matter accumulation, grain yield, water-nitrogen use efficiency, and economic benefits of soybean in Northwest China from 2021 to 2022. The results show that the dry matter accumulation, yield formation, water and nitrogen use efficiency, and economic benefits of soybean were improved under different mulching methods (SM, FM, and SFM) and nitrogen applications (N1-N3), and that the effect is the best when the nitrogen application rate is N2 and the mulching method is FM. As such, a conclusion could be drawn that suitable nitrogen application (120 kg ha−1) combined with film mulching was beneficial for the utilization of rainwater resources and soybean production in the dryland of Northwest China.

Sustainable agricultural practices to improve soil quality and productivity of soybean and upland rice

Combining cover crops with multifunctional microorganisms provides significant increments in the grain productivity of soybean and upland rice crops. However, there are still few studies that aimed to evaluate the effect of this combination on the productivity of agricultural systems. The objective of this study was to determine the effect of the mix of cover crops and the co-inoculation of multifunctional rhizobacteria on the quality of the soil, yield components, and on the grain yield of soybean and upland rice. The experimental design was in random blocks with 24 treatments in a 6x2x2 factorial scheme. Treatments were the combination of 6 (5 mix of cover crops (mixture of seeds of different cover crops species) and the control (fallow), 2 (upland rice and soybeans), 2 (co-inoculated (inoculation with two microorganisms) or not (no microorganisms), with four replications. Combination of cover crops provided an increase in Ca and Mn levels in the soil, increased activity of soil quality indicator enzymes (phosphatase and arylsulfatase), higher soybean yield, and higher number of upland rice panicles. The co-inoculation with multifunctional rhizobacteria led to an increase in phosphorus levels in the soil, the number of pods per plant, the mass of 100 grains for soybean cultivation, the number of grains per panicle, and productivity of upland rice. Therefore, a mix of cover crops, combined with the co-inoculation with multifunctional rhizobacteria are sustainable agricultural practices that can contribute to the improvement of soil quality and the increase of the productivity of soybean and upland rice crops

Improved soil fertility, plant nutrition and grain yield of soybean and millet following maize intercropped with forage grasses and crotalaria in the Brazilian savanna

Context Intercropping maize with tropical forages is known to provide multiple benefits for the agricultural sustainability in the Brazilian savanna. Despite that, more studies are needed to define strategies to improve soil quality and increase crop yield of subsequent crops. Aims This study aimed to evaluate the impacts of cultivating maize in monoculture or in double- and triple-intercropping with brachiaria and crotalaria on the chemical and microbiological attributes of soil, nutritional status of soybean, and the productivity of soybean and millet in succession in the cerrado of eastern Maranhão. Methods The intercropping systems implemented in 2017 were as follows: maize (Zea mays) + Urochloa ruzizienses (brachiaria); maize + Crotalaria juncea (crotalaria); maize + brachiaria + crotalaria; and monoculture maize as a control. In 2018 and 2019, soybean and millet were cultivated on the same plots. Key results The triple-intercropping promoted immediate improvement in the biological and chemical attributes of the soil, especially when compared with monoculture maize. Intercropping maize with brachiaria, with or without crotalaria, increased soybean productivity by 21% and millet by 44% in the subsequent year, compared with monoculture maize system. Intercropping maize with brachiaria, with or without crotalaria, increased the leaf concentrations of nitrogen, potassium, magnesium, and sulfur of the subsequent soybean crop, suggesting improved nutrient cycling with intercropped forages. Conclusions Intercropping maize + forage, especially brachiaria, can be recommended for crop rotation and succession systems in the Brazilian savanna. Implications These results quantified the benefits of crop rotation following intercropping with maize and forage, which can be an alternative for farmers in the Brazilian savanna.

The genetic basis of high-latitude adaptation in wild soybean

In many plants, flowering time is influenced by daylength as an adaptive response. In soybean (Glycine max) cultivars, however, photoperiodic flowering reduces crop yield and quality in high-latitude regions. Understanding the genetic basis of wild soybean (Glycine soja) adaptation to high latitudes could aid breeding of improved cultivars. Here, we identify the Tof4 (Time of flowering 4) locus, which encodes by an E1-like protein, E1La, that represses flowering and enhances adaptation to high latitudes in wild soybean. Moreover, we found that Tof4 physically associates with the promoters of two important FLOWERING LOCUS T (FT2a and FT5a) and with Tof5 to inhibit their transcription under long photoperiods. The effect of Tof4 on flowering and maturity is mediated by FT2a and FT5a proteins. Intriguingly, Tof4 and the key flowering repressor E1 independently but additively regulate flowering time, maturity, and grain yield in soybean. We determined that weak alleles of Tof4 have undergone natural selection, facilitating adaptation to high latitudes in wild soybean. Notably, over 71.5% of wild soybean accessions harbor the mutated alleles of Tof4 or a previously reported gain-of-function allele Tof5H2, suggesting that these two loci are the genetic basis of wild soybean adaptation to high latitudes. Almost no cultivated soybean carries the mutated tof4 allele. Introgression of the tof4-1 and Tof5H2 alleles into modern soybean or editing E1 family genes thus represents promising avenues to obtain early-maturity soybean, thereby improving productivity in high latitudes.