Tropical Legumes Research Articles

MORPHOLOGICAL CHARACTERIZATION OF PIGEON PEA [Cajanus cajan (L.) Millspaugh] ACCESSIONS FOR AGRONOMIC TRAITS IN ASSOSA DISTRICT, NORTHWESTERN ETHIOPIA

<p><strong>Background:</strong> Pigeon pea is a tropical grain legume being cultivated as important pulses for human food, feed and soil fertility improvement. Pigeon pea research in terms of crop improvement is still at a low level in Ethiopia. <strong>Objective: </strong>To estimate the Genetic variability of pigeon pea accessions with respect to important qualitative and quantitative traits and select high yielding grain and promising traits for variety development. <strong>Methodology</strong>: Treatments consisted in twenty two pigeon pea accessions (MPG1, MPG2, MPG3, MPG4, MPG5, MPG6, MPG7, MPG8, MPG9, MPG10, MPG11, MPG12, MPG13, MPG14, MPG15, MPG16, MPG17, MPG18, MPG19, MPG20, MPG21 and MPG22) collected from Assosa area. Treatments were laid out in a Randomized Complete Block Design with three replications. <strong>Results:</strong> Qualitative characteristics recorded for accessions showed different modalities and frequencies at vegetative growth stage with the qualitative traits dominated were semi-spreading growth habit 65 %, leaflet shape with lanceolate 70 %, color about 44 % of the accessions exhibited yellow, seed size where 55 % accounted large sized, seed color pattern: 52% of accessions showed plain, pod color where 56 % genotypes had purple, seed with red dominated was 50 % and 71 % of accessions had totally pigmented pod. With respect to quantitative traits, genotypes accessions MPG11 and MPG15 had relatively higher grain yield (> 4000 kg/ ha) with the highest grain yield recorded for genotype MPG18. <strong>Implications:</strong> The investigation of the present study for morphological evaluation of genotype Pigeon pea exhibited genetic variability among accession. <strong>Conclusion</strong>: Agronomic traits such as plant height, branches per plant, pods per plant, seeds per pod, pod length, pod width, hundred seed weight and grain yield for accessions were exhibited significant differences which suggest high yielding accessions could be directly recommended for production while others could be utilized effectively to develop high yielding varieties through hybridization followed by selection. </p>

Investigating Light and Water Optimization for Early Seedling Establishment in Albizia lebbeck (L.) Benth

Seedling growth, development, and establishment are vulnerable stages for trees, greatly influenced by two important environmental factors: light availability and soil moisture regime. This study investigated the interactive effects of light intensity and water availability on key early vegetative growth parameters of collar diameter, height, and the number of leaves in seedlings of the tropical legume tree Albizia lebbeck. The experiment utilized a 4×3 factorial design with four light intensity levels (L1 (75%), L2 (50%), L3 (25%), and L4 (100% as control)) and three watering frequencies (daily (W1), every three days (W2), weekly (W3)) in a nursery greenhouse. Measurements were recorded biweekly for ten weeks. The results showed that moderate light intensity of 50% coupled with adequate moisture supply by daily watering (L2W1) led to optimal seedling growth. This treatment combination resulted in the greatest mean collar diameter (3.62 mm), plant height (41.88 cm), and number of leaves (11). Growth was restricted under full light (L4) and insufficient light (L3). Limited water availability by watering weekly (W3) also suppressed growth metrics. However, there was no significant difference between daily watering (W1) and moderate watering frequency (W2). Strong intrinsic synchronization was observed between the collar diameter and plant height growth trajectories over time, reflecting coordinated lateral and vertical stem expansion regulated by developmental processes. Leaf proliferation showed partially decoupled dynamics from stem growth, indicating specialized control over leaf traits. Collar diameter, height, and the number of leaves were inherently intercorrelated, highlighting their co-dependence in generating resources and signals needed to sustain growth and development. The findings suggest that 50% light intensity and adequate moisture by watering every 1-3 days are optimal for nursery establishment of A. lebbeck seedlings to maximize early vegetative growth.

How the Inclusion of Pigeon Pea in Beef Cattle Diets Affects CH4 Intensity: An In Vitro Fermentation Assessment

Tropical pastures intercropped with legumes have been gaining prominence for increasing the efficiency of livestock production systems when compared to pasture monocultures. Here, our objective was to understand the fermentation processes that tropical grass and legumes underwent when included in ruminant diets, which have previously been found to optimize animal performance while reducing the intensity of enteric CH4 emissions. For this purpose, three areas containing pigeon pea (Cajanus cajan) and Urochloa spp. were sampled. Samples were dried, grounded, chemically analyzed, and included in five proportions (0%, 25%, 50%, 75%, and 100%) of pigeon pea in the diet. The diets were then analyzed using an in vitro fermentation technique. Statistical analysis was performed using SAS statistical software, considering bottles as replicates, and our results suggest that a 25% inclusion of pigeon pea is optimal for balancing CH4 mitigation and fermentation efficiency, highlighting the importance of more studies with this legume due to its benefits, especially as a supplement during drought periods that impact the production and quality of tropical pastures. It is important to consider that pigeon pea’s secondary compounds may have positively modulated the fermentation process and reduced CH4 emissions. However, excessive legume inclusion can negatively affect digestibility and animal health, impairing animal performance and the sustainability of pasture-based production systems.

Physical and biochemical characteristics of tropical grass and legume pastures grazed by lambs

AbstractLarge areas of tropical grass pastures are not grazed by lambs because of the difficulties in managing high growth rate swards with high selective animals. The objective of this study was to evaluate the physical and biochemical characteristics of tropical pastures offered to lambs in continuous grazing. An upright grass and a shrub legume were set out in three pasture types and grazed by lambs: (1) aruana grass monoculture (AG—Panicum maximum Jacq. cv. IZ‐5), (2) pigeon pea monoculture (PP—Cajanus cajan [L.] Millsp. cv. Anão) and (3) contiguous swards (CS), half of the paddock with AG (CSAG) and half with PP (CSPP). The pastures were evaluated for structural characteristics, production, nutritional composition and antioxidant concentrations in four periods over 92 days of continuous grazing by lambs. Hand plucking samples, similar to animal diet, were collected for chemical analysis. Regarding height, the PP legume monoculture after 42 days of grazing had uncontrollable growth by the lambs, reaching 1.2 m in height. This same legume but as a CS beside AG (CSPP) was maintained at a lower and similar height throughout the experimental periods. In general, the leaf:stem ratio of the different pastures decreased over the experimental periods from 0.7 to 0.2. In most periods, the CS showed intermediary nutritional quality compared to AG and PP. The alpha‐tocopherol content was similar among swards, with an average of 137.2 ± 13.67 mg/kg of green matter (p > .05). Pigeon pea showed the highest levels of total tannin and condensed tannin at 63 and 92 days (p < .05). The use of tropical grass together with a legume provides a better physical structure of the pigeon pea for grazing lambs than when monoculture of this species.

Unveiling Microbial Dynamics and Gene Expression in Legume–Buffel Grass Coculture Systems for Sustainable Agriculture

Legumes enhance pasture health and soil productivity by fixing atmospheric nitrogen and boosting soil microbiota. We investigated the effects of tropical pasture legumes, including butterfly pea (Clitoria ternatea), seca stylo (Stylosanthes scabra), desmanthus (Desmanthus virgatus), lablab (Lablab purpureus), and Wynn cassia (Chamaecrista rotundifolia), on the soil microbial community and buffel grass (Cenchrus ciliaris) gene expression. Additionally, we explored the impact of a phytogenic bioactive product (PHY) in the coculture system. A pot trial using soil enriched with cow paunch compost included four treatments: monoculture of buffel grass and five legume species with and without PHY supplementation and coculture of buffel grass with each legume species with and without PHY supplementation. Actinobacteriota and Firmicutes were the dominant bacterial phyla. Regardless of PHY application, the coculture of buffel grass with legumes positively influenced microbial composition and diversity. Transcriptomic analysis revealed significant gene expression changes in buffel grass shoots and roots, with each legume uniquely affecting nitrogen metabolism. Lablab and Wynn cassia exhibited similarities in modulating metabolic processes, butterfly pea contributed to mycotoxin detoxification, and desmanthus balanced cell death and growth. Seca stylo enhanced root cell growth and regeneration. These findings offer insights for optimizing legume–grass coculture systems, enhancing soil activity and promoting sustainable agriculture.

Effect of rock phosphate direct application on tropical legumes under different soil types of Sudan Savanna

ABSTRACT Direct application of low-grade rock phosphate (RP) is a less expensive alternative than the application of chemical phosphorus (P) for small holders relying on nutrient-deficient weathered soils. However, the effect of RP application on growth and yield is unstable for different crop species and soil water conditions. To identify legume species effective for RP direct application, five tropical legumes (cowpea, groundnut, bambara nut, mung bean, and soybean) were tested under two soil types with different water-holding capacities in Sudan Savanna; Lixisols and Plinthosols. The experiment was conducted under three conditions of P treatment, namely, RP application, triple super phosphate (TSP) application, and no phosphorus fertilizer application (0P). Under RP treatment, higher grain yield was obtained in Lixisols, which had a higher water-holding capacity. However, the yield increase was suppressed in the year with more rainfall owing to drastic changes in the soil moisture content, which caused excessive soil moisture stress during vegetative growth periods. Among the five legume species, cowpea and groundnut showed higher grain yields under the RP treatment than did other species. RP application increased shoot biomass but caused small changes in the shoot P and N concentrations. Soybean in Plinthosols had the highest yield ratio of RP/0P, but the absolute yield was low because of the insufficient soil water availability caused by the low water-holding capacity. RP direct application can assist shoot growth and yield, but it rarely compensates for basal yield differences between soil types and among legume species.

Functional validation of mungbean LEA protein coding gene in bacterial expression system confers salt stress tolerance

Mungbean (Vigna radiata R. Wilczek) is a major tropical food grain legume that is widely cultivated in tropical part of the world. Mungbean like other plants, tolerate and survive limited water situation owing to expression of stress associated proteins that offers membrane stability and cell protection. Late Embryogenesis Abundant (LEA) proteins are among the group of low molecular weight proteins, that play diverse roles in stress protection in several species of plants and animals. A LEA protein coding gene VrLEA2 was isolated from mungbean and its role in stress tolerance has been demonstrated using a bacterial expression system. VrLEA2 gene isolated was of size 893 bp and characterized as a group 1 LEA protein based on the sequence signature motif with presence of hydrophilic domain and a characteristic 20-mer conserved amino acids motif. VrLEA2 gene was cloned into a bacterial expression vector, pET 28a (+), transformed into the E.coli BL21 (DE3) cells for recombinant protein expression and subsequently subjected to antibiotic selection with kanamycin. Functional validation of the VrLEA2 for salt stress tolerance with varied concentration of NaCl (0 mM to 600 mM) showed alteration in colony morphology and reduction in the number of colonies in control compared to the transformed cells demonstrating the improved survival rate of cells expressing VrLEA2 protein. These findings indicate the best use of bacterial expression system for functional validation of plant proteins under stressed environments.

Association mapping of important agronomic traits in Mucuna pruriens (L.) DC.

BackgroundThe tropical legume Mucuna pruriens (L.) DC. can meet three agricultural needs: low-cost protein, high-value medicines, and green manure or cover crops. But like other underutilized crops, it needs more modern breeding resources. Identifying marker-trait associations (MTAs) can facilitate marker-assisted breeding and crop improvement. Recent studies have demonstrated the feasibility of identifying MTAs using a small number of accessions (< 100). We have characterized a panel of 70 M. pruriens accessions across two consecutive years and performed association analysis for 16 phenotypic traits related to seed (seed length, seed width, seed thickness, seed yield per plant, hundred seed weight); pod (pod length, pod width, number of pods per cluster, number of pods per plant); inflorescence (inflorescence length, flower buds per inflorescence, flower length, pedicel length), and biochemical attributes (L-DOPA, total protein, total carbohydrate), using 66 genic-microsatellite markers following mixed linear model.ResultsThe results showed significant phenotypic (P < 0.05) and genetic diversity (Shannon’s information index, I = 0.62) in our germplasm collection. Many tested traits were highly heritable (broad-sense heritability ranging from 42.86 to 99.93%). A total of 15 MTAs was detected at an adjusted significance level of P < 5.55 × 10− 3 for nine traits (seed length, seed thickness, seed width, hundred seed weight, seed yield per plant, inflorescence length, flower buds per inflorescence, flower length, and petiole length), contributed by 10 SSR markers (MPU_19, MPU_42, MPU_54, MPU_57, MPU_58, MPU_83, MPU_89, MPU_108, MPU_111, and MPU_122.) with phenotypic variance explained (PVE) ranging from 14.7 to 31.1%. Out of the ten trait-associated markers, the BLAST analysis revealed putative functions of seven markers, except MPU_57, MPU_58, and MPU_83.ConclusionFifteen MTAs identified for important traits with phenotypic variance explained > 10% from mixed linear model offer a solid resource base for improving this crop. This is the first report on association mapping in M. pruriens and our results are expected to assist with marker-assisted breeding and identifying candidate genes in this promising legume.

Nutritive value and condensed tannins of tree legumes in silvopasture systems

Introducing legumes into C4-dominated tropical pastures, may enhance their sustainability but has some pasture management constraints. One potential alternative is using arboreal legumes, but several of these species have relatively high condensed tannin (CT) concentrations, which negatively impact forage quality. There is limited knowledge, however, on how arboreal legume leaf CT content varies over the year and how this might impact forage quality. The objective of this 2 year study was to assess the seasonal variation of CT and nutritive value for ruminants of the tropical tree legumes gliricidia [Gliricidia sepium (Jacq.) Kunth ex. Walp.] and mimosa (Mimosa caesalpiniifolia Benth). The research was carried out in the sub-humid tropical region of Brazil on well-established pastures in which either legume was present with signalgrass (Urochloa decumbens Stapf.). We determined CT and nitrogen concentrations, in vitro digestible organic matter (IVDOM), and leaf δ13C and δ15N from January to October of 2017 and 2018. All parameters were affected (P < 0.05) by the interaction between legume species and sampling time, with generally higher leaf CT content for mimosa than gliricidia, and both were reduced at the start of the dry season, although much more drastically for mimosa. The IVDOM was strongly affected by CT content and increased at the start of the dry season, coincidentally when C4 grass forage quality typically decreased. There is a marked species effect, with CT from gliricidia impacting IVDOM more than the same CT content from mimosa. While N concentration from mimosa also increased at the start of the dry season, that for gliricidia did not vary over the year. We conclude that although these arboreal legumes have relatively high CT contents, these reduce during the dry season when CT concentrations coinciding with a reduced forage quality as the protein content for C4 grasses is usually inadequate in this season.

Enhancement of ensiling qualify of gamba grass (Andropogon gayanus Kunch) with tropical legume forages

Enhancement of ensiling qualify of gamba grass (Andropogon gayanus Kunch) with tropical legume forages

Effects of dietary Adansonia digitata L. (baobab) seed meal on growth performance and carcass characteristics of broiler chickens: A systematic review and meta-analysis

Abstract The seeds of lesser-known tropical legume trees are currently being promoted as a cost-effective method of increasing broiler productivity, especially in low- and middle-income countries. Several feeding trials have evaluated the effects of baobab seed meal (BSM) on broiler chicken productivity. However, due to differences in experimental conditions among feeding trials, drawing broad conclusions using this large volume of data appears difficult. Thus, the meta-analytic effect of BSM on growth performance [i.e., feed intake, feed conversion ratio (FCR), and body weight gain (BWG)] and carcass characteristics of broilers were investigated using 14 peer-reviewed published articles. These articles were retrieved via a systematic search conducted on Google Scholar, ScienceDirect, Elicit.com, and PubMed databases. The effect size was calculated via a random effect model, and results were expressed as standardised mean differences (SMD) at 95% confidence intervals. The pooled results showed that broilers fed BSM had significantly lower BWG (SMD = −0.77; −0.19, −0.30; p &lt; 0.001), dressed carcass weight (SMD = −0.84; −1.44, −0.23; p = 0.007), and higher FCR (SMD = 0.55; 0.19, 0.91; p &lt; 0.001) than those fed control diets. However, feed intake, dressing percentage, and weights of breast, thigh, and drumstick were not significantly affected. Subgroup analyses showed that the Marshall strain-fed BSM-based diets had significantly heavier BWG (p &lt; 0.001) than the Hubbard, Ross, and Anak strains. Similarly, results revealed that broilers fed soaked and roasted BSM had significantly better FCR and BWG than broilers fed sundried and fermented BSM. Broilers fed BSM-based diets from days 29–56 (SMD = 0.17; −0.51, 0.84; p = 0.622) and days 1−56 (SMD = −0.89; −1.41, −0.36; p &lt; 0.001) had significantly improved FCR compared to those offered BSM-based diets from days 1–21 (SMD = 2.58; 1.65, 3.51; p &lt; 0.001), days 1–28 (SMD = 0.85; 0.35, 1.34; p &lt; 0.001), and days 22–42 (SMD = 1.82; 1.02, 2.62; p &lt; 0.001). Similarly, broilers fed BSM-based diets from days 29–56 (SMD = 0.21; −0.38, 0.79; p = 0.484) and days 1−56 (SMD = 0.92; 0.16, 1.69; p = 0.018) had significantly higher BWG than those offered BSM-based diets from days 1–21 (SMD = −3.39; −4.41, −2.37; p &lt; 0.001), days 1–28 (SMD = −1.32; −1.91, −0.72; p &lt; 0.001), and days 22–42 (SMD = −2.24; −2.75, 1.73; p &lt; 0.001). Meta-regression revealed a low to moderate effect of processing methods, broiler strains, inclusion level, and feeding duration as covariates, explaining most of the sources of heterogeneity. In conclusion, broilers fed 1–10% of soaked, and roasted BSM from days 1 to 56 had improved growth performance parameters when compared to those on the control.

Evolutionary history and root trait coordination predict nutrient strategy in tropical legume trees.

Plants express diverse nutrient use and acquisition traits, but it is unclear how trait combinations at the species level are constrained by phylogeny, trait coordination, or trade-offs in resource investment. One trait - nitrogen (N) fixation - is assumed to correlate with other traits and used to define plant functional groups, despite potential confounding effects of phylogeny. We quantified growth, carbon metabolism, fixation rate, root phosphatase activity (RPA), mycorrhizal colonization, and leaf and root morphology/chemistry across 22 species of fixing and nonfixing tropical Fabaceae trees under common conditions. Belowground trait variation was high even among closely related species, and most traits displayed a phylogenetic signal, including N-fixation rate and nodule biomass. Across species, we observed strong positive correlations between physiological traits such as RPA and root respiration. RPA increased ~ fourfold per unit increase in fixation, supporting the debated hypothesis that N-fixers 'trade' N for phosphatases to enhance phosphorus acquisition. Specific root length and root N differed between functional groups, though for other traits, apparent differences became nonsignificant after accounting for phylogenetic nonindependence. We conclude that evolutionary history, trait coordination, and fixation ability contribute to nutrient trait expression at the species level, and recommend explicitly considering phylogeny in analyses of functional groupings.

Nitrogen-fixing bacteria boost floral attractiveness in a tropical legume species during nutrient limitation.

Legumes establish mutualistic interactions with pollinators and nitrogen (N)-fixing bacteria that are critical for plant reproduction and ecosystem functioning. However, we know little about how N-fixing bacteria and soil nutrient availability affect plant attractiveness to pollinators. In a two-factorial greenhouse experiment to assess the impact of N-fixing bacteria and soil types on floral traits and attractiveness to pollinators in Chamaecrista latistipula (Fabaceae), plants were inoculated with N-fixing bacteria (NF+) or not (NF-) and grown in N-rich organic soil (+N organic soil) or N-poor sand soil (-N sand soil). We counted buds and flowers and measured plant size during the experiment. We also measured leaf, petal, and anther reflectance with a spectrophotometer and analyzed reflectance curves. Using the bee hexagon model, we estimated chromatic contrasts, a crucial visual cues for attracting bees that are nearby and more distant. NF+ plants in -N sand soil had a high floral display and color contrasts. On the other hand, NF- plants and/or plants in +N organic soil had severely reduced floral display and color contrasts, decreasing floral attractiveness to bee pollinators. Our findings indicate that the N-fixing bacteria positively impact pollination, particularly when nutrients are limited. This study provides insights into the dynamics of plant-pollinator interactions and underscores the significant influence of root symbionts on key floral traits within tropical ecosystems. These results contribute to understanding the mechanisms governing mutualisms and their consequences for plant fitness and ecological dynamics.

Arbuscular mycorrhizal fungi increase the tolerance to excess zinc of a tropical legume grown in iron-ore mining waste

Arbuscular mycorrhizal fungi (AMF) might amend the toxicity of trace elements and improve the nutritional status of plants, but little is known about these responses in tropical native plants in iron-ore-impacted sites with excess zinc (Zn). We evaluated how the association with AMF contributes to the resistance capacity of Stryphnodendron adstringens to high Zn concentrations in mining waste. Seeds were sown in pots containing iron-ore mining waste with different concentrations of Zn (0, 100, 200, 400 and 600 mg L−1) and two conditions (inoculated or not with AMF). The biomass accumulation and physiological processes were severely impacted in the mining waste with Zn concentration above 100 mg L−1. The relative growth rate (RGR) and the concentration of phosphorus (P) in the shoot were higher in the AMF-inoculated plants, mainly when cultivated without Zn excess. Non-inoculated plants presented the lowest net photosynthetic rate (An) mainly due to impairment in light use efficiency, especially under Zn excess. The treatments did not change stomatal conductance, transpiration, Rubisco carboxylation rate, triose-phosphate utilization and respiration rate. The AMF improved the plant resistance capacity in mining waste substrate by promoting decreased oxidative damage, ameliorated P nutrition, higher RGR, root biomass and An.

Nitrogen niche partitioning between tropical legumes and grasses conditionally weakens under elevated CO2

Abstract Plant community biodiversity can be maintained, at least partially, by shifts in species interactions between facilitation and competition for resources as environmental conditions change. These interactions also drive ecosystem functioning, including productivity, and can promote over‐yielding‐ an ecosystem service prioritized in agro‐ecosystems, such as pastures, that occurs when multiple species together are more productive than the component species alone. Importantly, species interactions that can result in over‐yielding may shift in response to rising CO2 concentrations and changes in resource availability, and the consequences these shifts have on production is uncertain especially in the context of tropical mixed‐species grasslands. We examined the relative performance of two species pairs of tropical pasture grasses and legumes growing in monoculture and mixtures in a glasshouse experiment manipulating CO2. We investigated how over‐yielding can arise from nitrogen (N) niche partitioning and biotic facilitation using stable isotopes to differentiate soil N from biological N fixation (BNF) within N acquisition into above‐ground biomass for these two‐species mixtures. We found that N niche partitioning in species‐level use of soil N versus BNF drove species interactions in mixtures. Importantly partitioning and overyielding were generally reduced under elevated CO2. However, this finding was mixture‐dependent based on biomass of dominant species in mixtures and the strength of selection effects for the dominant species. This study demonstrates that rising atmospheric CO2 may alter niche partitioning between co‐occurring species, with negative implications for the over‐yielding benefits predicted for legume‐grass mixtures in working landscapes with tropical species. Furthermore, these changes in inter‐species interactions may have consequences for grassland composition that are not yet considered in larger‐scale projections for impacts of climate change and species distributions. Read the free Plain Language Summary for this article on the Journal blog.

Cratylia argentea – review of a tropical shrub legume: Biology and agronomy

Cratylia argentea – review of a tropical shrub legume: Biology and agronomy

Cratylia argentea – review of a tropical shrub legume: Quality and utilization

Cratylia argentea – review of a tropical shrub legume: Quality and utilization

Preferential Phosphorus Placement Improves the Productivity and Competitiveness of Tropical Pasture Legumes

ABSTRACTExtensive grazing systems often receive minimal fertiliser due to the risk associated with using relatively expensive inputs. Nevertheless, nutrient applications are known to improve pasture productivity, and the benefit of applying fertiliser is being more widely accepted. Two tropical pasture mixes (Digit/Desmanthus and Rhodes/Centro) were established in plastic boxes containing phosphorus (P) responsive soil to investigate shoot yield and P fertiliser recovery. The grasses and legumes were planted in separate rows, and three P treatments were applied along with the seed (‘BOTH low‐P’ had 2 kg P ha−1 banded below both components, ‘BOTH high‐P’ had 12 kg P ha−1 banded below both components and ‘LEGUME superhigh‐P’ had 12 kg P ha−1 banded below the legume only). The P applied below the legumes was labelled with 32P‐radioisotope tracer. When P fertiliser was applied below both components, the grasses consistently out‐yielded the legumes (avg. legume content = 29%). Preferential fertiliser application below the legumes increased the average legume content of the two pasture mixes to 66%. Legume tissue P derived from applied P fertiliser increased from 20% to 77% as the P application rate was increased. However, total recovery of applied P by the legumes was relatively low in each of the treatments (≤ 7% of applied P). These collective results demonstrate that a preferential application of P fertiliser can benefit legume productivity, with applied P being a significant proportion of plant tissue P. Although only a small proportion of applied P was recovered within the seven‐week growth period, it is expected that this fertiliser application at planting will remain beneficial for a large proportion of the growing season following pasture establishment.

Differential selection of yield and quality traits has shaped genomic signatures of cowpea domestication and improvement.

Cowpeas (tropical legumes) are important in ensuring food and nutritional security in developing countries, especially in sub-Saharan Africa. Herein, we report two high-quality genome assemblies of grain and vegetable cowpeas and we re-sequenced 344 accessions to characterize the genomic variations landscape. We identified 39 loci for ten important agronomic traits and more than 541 potential loci that underwent selection during cowpea domestication and improvement. In particular, the synchronous selections of the pod-shattering loci and their neighboring stress-relevant loci probably led to the enhancement of pod-shattering resistance and the compromise of stress resistance during the domestication from grain to vegetable cowpeas. Moreover, differential selections on multiple loci associated with pod length, grain number per pod, seed weight, pod and seed soluble sugars, and seed crude proteins shaped the yield and quality diversity in cowpeas. Our findings provide genomic insights into cowpea domestication and improvement footprints, enabling further genome-informed cultivar improvement of cowpeas.

Setting up Agrobacterium tumefaciens-mediated transformation of the tropical legume Aeschynomene evenia, a powerful tool for studying gene function in Nod Factor-independent symbiosis.

Most legumes are able to develop a root nodule symbiosis in association with proteobacteria collectively called rhizobia. Among them, the tropical species Aeschynomene evenia has the remarkable property of being nodulated by photosynthetic Rhizobia without the intervention of Nod Factors (NodF). Thereby, A. evenia has emerged as a working model for investigating the NodF-independent symbiosis. Despite the availability of numerous resources and tools to study the molecular basis of this atypical symbiosis, the lack of a transformation system based on Agrobacterium tumefaciens significantly limits the range of functional approaches. In this report, we present the development of a stable genetic transformation procedure for A. evenia. We first assessed its regeneration capability and found that a combination of two growth regulators, NAA (= Naphthalene Acetic Acid) and BAP (= 6-BenzylAminoPurine) allows the induction of budding calli from epicotyls, hypocotyls and cotyledons with a high efficiency in media containing 0,5 μM NAA (up to 100% of calli with continuous stem proliferation). To optimize the generation of transgenic lines, we employed A. tumefaciens strain EHA105 harboring a binary vector carrying the hygromycin resistance gene and the mCherry fluorescent marker. Epicotyls and hypocotyls were used as the starting material for this process. We have found that one growth medium containing a combination of NAA (0,5 μM) and BAP (2,2 μM) was sufficient to induce callogenesis and A. tumefaciens strain EHA105 was sufficiently virulent to yield a high number of transformed calli. This simple and efficient method constitutes a valuable tool that will greatly facilitate the functional studies in NodF-independent symbiosis.