Seed Nitrogen Content Research Articles

The biostimulatory effect of humic‐based soil amendment on plant growth, root nodulation, symbiotic nitrogen fixation and yield of field pea (Pisum sativum L.)

AbstractIntroductionPea is one of the most important pulse legumes globally due to its high protein, which is due to its ability to fix atmospheric nitrogen through a symbiotic relationship with nitrogen‐fixing rhizobia. Symbiotic nitrogen fixation (SNF) should be optimized to maximize nitrogen fixation and achieve higher yields with more grain protein. The use of humic‐based soil amendments in crop production has garnered considerable attention in recent years due to their biostimulatory effect in improving plant growth, yield, nutritional quality and soil health. This study examines the impact of a humic‐based soil amendment (Humalite) on root nodulation, SNF, plant growth, yield and grain protein of pea.Materials and MethodsChemical characterization was performed using Fourier transform infrared spectroscopy (FTIR). Pea plants inoculated with Rhizobia were grown in pots under greenhouse conditions with five different Humalite rates (0, 200, 400, 800 and 1600 kg ha−1). SNF capacity was assessed using the 15N‐isotope dilution method.ResultsFTIR analysis revealed the abundant presence of hydroxyl (‐OH) and carboxyl (‐CO) functional groups in Humalite. Plants treated with Humalite displayed augmented root traits [root length (21%–50%), root surface area (24%–51%), volume (26%–53%), average nodule weight (11%–91%)], plant biomass [shoots (13%–29%) and roots (29%–54%)], shoot nitrogen concentration (12%–33%), shoot total nitrogen content (38%–53%), percentage nitrogen derived from the atmosphere (8%–14%) and total shoot nitrogen fixed (48%–80%) compared to the control plants at the flowering stage. Furthermore, at seed maturity stage, plants treated with Humalite at 400 and 1600 kg ha−1 exhibited a significant increase in plant biomass (4%–14%), number of seeds (8%–16%), seed weight (3%–11%), seed nitrogen content (8%–20%) and total seed nitrogen fixed (7%–22%) compared to the control plants.ConclusionsThese findings demonstrate that humic‐based soil amendment can effectively enhance plant growth, root nodulation, SNF and seed yield, thereby supporting sustainable agricultural practices.

The effect of foliar application of plant growth regulators on functional and qualitative characteristics of wheat (Triticum aestivum L.) under salinity and drought stress conditions

This study aimed to investigate the effect of salinity and water stress on the physiological and functional characteristics of winter wheat (Triticum aestivum L.) under the foliar application of plant growth regulators (PGRs). The experiment was carried out as a split plot based on a randomized complete block design with three replications in two environments. In each environment, water stress at two irrigation levels (after 90 and 120 mm of pan evaporation) and with two EC of 1.5 and 10 dS/m in the main plots and spraying of PGRs including salicylic acid (SA), gibberellic acid (GA3), and cytokinins (CK) (purine) content with a concentration of 100 ppm and the control treatment (spraying solution with normal water) were placed in subplots. Results indicated that all treatments caused significant increases in functional and qualitative characteristics and yield of Triticum aestivum L. The saline environment and irrigation level after 120 mm of pan evaporation caused a reduction in grain yield in all traits except for seed proline, seed nitrogen content, and seed protein content. Also, the combined foliar application of GA3 + CK + SA increased yield in most traits. The highest RWC of flag leaves was observed in the foliar application of GA3 + SA (3.36 kg/ha) and then in the foliar application of GA3 + SA + CK (57.87 kg/ha). GA3 interacts with PGR spraying to balance another development under saline and non-saline conditions.

Nutrient and growth elucidation of a novel coated urea on oilseed rape in three main cultivation areas

A novel coated urea (MVCU) was prepared, and its application effect was verified by field trials of oilseed rape in three main cultivation areas. Meanwhile, the nutrient release and coating layer changes of MVCU in static water at 25 °C and different soils were systematically evaluated. MVCU showed a long nutrient release time under static water (77 days) and soil incubation (140 days) conditions due to the slow degradation of the coating layer in MVCU, and its nitrogen release coincided well with oilseed rape nitrogen demand. The above results were further confirmed by FT-IR spectra and SEM analysis. Compared with conventional urea (U), the field trials of MVCU in the three main cultivation areas showed high nitrogen utilization efficiency and yield advantages in oilseed rape. The field trials results indicated that the MVCU significantly enhanced the aboveground dry matter (28.7%), the seed nitrogen concentration (9.5%) and aboveground nitrogen accumulation (42.5%) of oilseed rape at the mature stage as compared to that of the U. The oilseed rape yield enhanced by 932.8 kg/hm2, the average growth rate was 65.1%, and nitrogen utilization efficiency increased by 21.2%. In short, MVCU has the advantages of excellent slow-release performance and strong applicability, and its yield-increasing effect on oilseed rape could reach or even be better than that of traditional fertilization.

PHYSIOLOGICAL AND BIOCHEMICAL COMPOSITION OF SUNFLOWER (HELIANTHUS ANNUUS L.)

The evaluation of sunflower (Helianthus annuus L.) cultivar leaves belonging to different exotic and local genotypes for physiological traits, viz., chlorophyll a and b, total chlorophyll, carotenoid pigments, and concentration of total pigments transpired spectrophotometrically. The exotic sunflower genotypes used in the study consisted of 9859 (USA), 30837 (Australia), 33673 (France), 9843 and 30835 (Turkey), 9853 and 9848 (Russia), and a local cultivar Jakhongir (Uzbekistan). In the budding phase, the exotic accession 33673 (France) showed higher contents of chlorophyll a and b, carotenoids, and total pigments (17.8  0.55, 6.61  0.40, 5.82  0.19, and 24.47  0.95 mg/ml, respectively). For the flowering phase, exotic genotype 30835 (Turkey) excelled for chlorophyll a and b, carotenoids, and total pigments concentration (17.10  0.37, 6.31  0.24, 5.42  0.24, and 23.41  0.55 mg/ml, respectively). In the ripening phase, the amount of chlorophyll a and carotenoids were 16.64  0.84 and 5.82  0.12 mg/ml, respectively, in genotype 9853 (Russia), and chlorophyll b and total pigments correspond to 6.04  0.33 mg/ml and 21.19  0.57 mg/ml in the local cultivar Jakhongir. No significant quantitative variations were evident for nitrogen content and total protein content in sunflower genotype seeds. However, higher values of total protein content (21.8%) manifested in the exotic genotypes, i.e., 30837 (Australia), 33673 (France), and 9848 (Russia). During 2021, the seed oil content ranged from 31.9%  0.51% to 54.4%  0.87%, while the highest oil content (54.4%  0.87%) emerged in genotype 9853 (Russia). In 2022 planting, the sunflower seeds’ highest fat content percentage surfaced in sample 9848 (Russia), 53.99%  0.14%. In addition, genotype 9853 (Russia) also contained various micro-macro elements, i.e., Mg, Al, Ca, Fe, Sr, and Ba, compared with the rest of the sunflower genotypes.

The cytoprotective co-chaperone, AtBAG4, supports increased nodulation and seed protein content in chickpea without yield penalty

Drought and extreme temperatures significantly limit chickpea productivity worldwide. The regulation of plant programmed cell death pathways is emerging as a key component of plant stress responses to maintain homeostasis at the cellular-level and a potential target for crop improvement against environmental stresses. Arabidopsis thaliana Bcl-2 associated athanogene 4 (AtBAG4) is a cytoprotective co-chaperone that is linked to plant responses to environmental stress. Here, we investigate whether exogenous expression of AtBAG4 impacts nodulation and nitrogen fixation. Transgenic chickpea lines expressing AtBAG4 are more drought tolerant and produce higher yields under drought stress. Furthermore, AtBAG4 expression supports higher nodulation, photosynthetic levels, nitrogen fixation and seed nitrogen content under well-watered conditions when the plants were inoculated with Mesorhizobium ciceri. Together, our findings illustrate the potential use of cytoprotective chaperones to improve crop performance at least in the greenhouse in future uncertain climates with little to no risk to yield under well-watered and water-deficient conditions.

Reducing chlorophyll levels in seed-filling stages results in higher seed nitrogen without impacting canopy carbon assimilation.

Chlorophyll is the major light-absorbing pigment for plant photosynthesis. While evolution has been selected for high chlorophyll content in leaves, previous work suggests that domesticated crops grown in modern high-density agricultural environments overinvest in chlorophyll production, thereby lowering light use and nitrogen use efficiency. To investigate the potential benefits of reducing chlorophyll levels, we created ethanol-inducible RNAi tobacco mutants that suppress Mg-chelatase subunit I (CHLI) with small RNA within 3 h of induction and reduce chlorophyll within 5 days in field conditions. We initiated chlorophyll reduction later in plant development to avoid the highly sensitive seedling stage and to allow young plants to have full green leaves to maximise light interception before canopy formation. This study demonstrated that leaf chlorophyll reduction >60% during seed-filling stages increased tobacco seed nitrogen concentration by as much as 17% while canopy photosynthesis, biomass and seed yields were maintained. These results indicate that time-specific reduction of chlorophyll could be a novel strategy that decouples the inverse relationship between yield and seed nitrogen by utilising saved nitrogen from the reduction of chlorophyll while maintaining full carbon assimilation capacity.

Plant growth regulators improve nitrogen metabolism, yield, and quality of soybean–rhizobia symbiosis

PurposeIn recent years, considerable research has been conducted on the use of plant growth regulators (PGRs) to improve crop yields. Large amounts of PGRs are applied to regulate crop growth. However, few studies have assessed the impact of PGRs, which leave soil residues, on soil microorganisms, especially rhizobia.MethodsIn this study, the influence of inoculation of soybean roots with Sinorhizobium fredii and Bradyrhizobium japonicum exposed to gibberellin A3 (GA3) and mepiquat chloride (MC) on nodule number, nitrogenase activity, and a symbiotic nitrogen fixation gene (fixA) expression was studied. The nitrate content, free amino acids, and nitrate reductase activity of the roots, and seed yield and quality of soybean were measured.ResultNodulation was promoted to some extent, whereas nitrogenase activity and fixA expression were inhibited to some extent by treatment with GA3; however, these effects were reversed by treatment with MC. In a pot experiment to study phenotypic characteristics, rhizobia treatment in combination with GA3 or MC significantly improved soybean yield and seed nitrogen content, and increased the root nitrate content, free amino acid content, and nitrate reductase activity.ConclusionThe results indicated that PGRs, which leave soil residues, have significant positive effects on the growth and activity of soybean and rhizobia.

The Genotypic Variability among Short-Season Soybean Cultivars for Nitrogen Fixation under Drought Stress.

Soybean fixes atmospheric nitrogen through the symbiotic rhizobia bacteria that inhabit root nodules. Drought stress negatively affect symbiotic nitrogen fixation (SNF) in soybean. The main objective of this study was to identify allelic variations associated with SNF in short-season Canadian soybean varieties under drought stress. A diversity panel of 103 early-maturity Canadian soybean varieties was evaluated under greenhouse conditions to determine SNF-related traits under drought stress. Drought was imposed after three weeks of plant growth, where plants were maintained at 30% field capacity (FC) (drought) and 80% FC (well-watered) until seed maturity. Under drought stress, soybean plants had lower seed yield, yield components, seed nitrogen content, % nitrogen derived from the atmosphere (%Ndfa), and total seed nitrogen fixed compared to those under well-watered conditions. Significant genotypic variability among soybean varieties was found for yield, yield parameters, and nitrogen fixation traits. A genome-wide association study (GWAS) was conducted using 2.16 M single nucleotide single nucleotide polymorphisms (SNPs) for different yield and nitrogen fixation related parameters for 30% FC and their relative performance (30% FC/80% FC). In total, five quantitative trait locus (QTL) regions, including candidate genes, were detected as significantly associated with %Ndfa under drought stress and relative performance. These genes can potentially aid in future breeding efforts to develop drought-resistant soybean varieties.

Genetic variation in four maturity genes and photoperiod insensitivity effects on the yield components and on the growth duration periods of soybean

Soybean (Glycine max (L.) Merr.) is a typical short-day and thermophilic crop. Absence of or low sensitivity to photoperiod is necessary for short-day crops to adapt to high latitudes. Photoperiod insensitivity in soybeans is controlled by two genetic systems and involves three important maturity genes: E1, a repressor for two soybean orthologs of Arabidopsis FLOWERING LOCUS T, and E3 and E4, which are phytochrome A genes. The aim of this work was to investigate the role of four maturity genes (E1 through E4) on the yield components, seed quality and on phasic development of near isogenic by E genes lines of soybean: short-day (SD) lines with genotype e1E2E3E4e5E7, e1E2E3e4e5E7, E1e2e3E4e5E7 and photoperiodic insensitive (PPI) lines with genotype e1e2E3E4e5E7, e1e2e3E4e5E7 under a long photoperiod (the natural day length of 50 latitude) conditions and short day conditions. The results of the study showed that soybean development processes under conditions of different day lengths depend on the dominant/recessive state of the main maturity genes. In addition, the response to the photoperiod depends on certain combinations of genes. SD lines began flowering on average 16.9% later under the conditions of a natural long photoperiod. Dominant alleles of genes E1 and E3 extended the pre- and post-flowering phases under conditions of exposure to long and short photoperiods. The dominant allele of the E1 gene delayed the onset of flowering by an average of 26.9%, and the period of full maturity by 39.8% compared to the recessive e1. The dominant allele of the E3 gene, compared to the recessive e3, lengthened the transition to flowering by an average of 16.1%, and the period of full ripeness by 27.1%. The dominant allele of the E2 gene lengthened the duration of the vegetative phase by 20% under the conditions of a long photoperiod. No significant influence of the dominant E4 allele on the duration of the vegetative and generative phases of soybean development was found in our study. PPI lines begin flowering under the conditions of a long and short photoperiod at the same time, but the phases of flowering and full seed maturity in the line with genotype e1e2e3E4e5E7 occurred earlier, due to the loss of the photoperiod sensitivity of the E3 gene. PPI line with genotype e1e2e3E4e5E7 proved to be the most insensitive line to the effect of different photoperiod durations among the studied lines. It was shown that the dominant alleles of E1–E4 maturity genes reduced the parameters of seed weight per plant and the weight of 1000 seeds under the conditions of a natural long photoperiod in comparison with recessive alleles of these genes. The maximum weight of seeds per plant and the weight of 1000 seeds were recorded in the PPI line with genotype e1e2e3E4e5E7. It should be noted that the dominant alleles E1 and E3 increased yield under conditions of a short photoperiod. Maturity genes had different effects on the biochemical composition of seeds. It was shown that soybean lines with dominant E1, E2 and E4 genes showed a higher content of starch and a lower content of total nitrogen and oil in seeds under natural photoperiod conditions compared to lines with recessive alleles of these genes. The dominant E3 allele reduced the oil content and did not affect the starch and total nitrogen content of seeds under long day conditions compared to the recessive e3 allele. The analysis of the effect of photoperiod on the timing of phenophases, yield structure indicators and biochemical composition of seeds in soybean plants with different sensitivity to photoperiod showed that the PPI line with the genotype e1e2e3E4e5E7 was the most adapted to the natural conditions of 50 degrees latitude. The PPI line with the genotype e1e2e3E4e5E7 was characterized by the shortest phases of days from sowing to flowering and full maturity. As a result, this line had the shortest growing season without reducing the yield and seed quality. Clearly, photoperiod had strong effects on all stages of plant reproduction and often acted indirectly, as shown by delayed responses expressed in later phases of development. The obtained results can be useful for the selection of soybean cultivars adapted to the climatic conditions of cultivation of Kharkiv region.

Efficiency of Some Herbicides and Fungicides on Management of Common Bean Damping-off and Root-rot Diseases

The three tested herbicides and fungicides caused significant inhibitory effect on the growth of Fusarium solani and Rhizoctonia solani the causal of common bean damping-off and root-rot diseases compared with control treatment. This inhibition was gradually increased by increasing the concentration of the tested herbicides and fungicides. Moreover, the fungus F. solani was greatly affected by the tested herbicides and fungicides than the fungus R. solani. Furthermore, the tested fungicides were more efficient than the herbicides in this regard. There was significant decrease in both damping-off and root-rot severity with significant increase in the survived plants due to the treatment with the tested herbicides and fungicides. No damping-off and root-rot were recorded in case the tested herbicides, fungicides and non-infested soil. Highest percentages of damping-off, root-rot and lowest survived plant were recorded in case of soil infested with any of the two pathogens. In addition, the combination between the tested herbicides and fungicides with any of the tested pathogens resulted in significant reduction to damping-off and root-rot severity with significant increase in the survived plants compared to plants grown in soil infested with any of the two tested pathogens and did not receive such a treatment. The treatment with any of the tested herbicides and fungicides and grown in soil infested with any of the two pathogens resulted in remarkable increase in the total phenolic compounds compared to the values of plants grown in soil infested with any of the two causal fungi (control plants). Gradual increase in the values of total phenolic compounds was occurred by increasing the time of inoculation with the pathogens and the highest increase in the total phenolic compounds was occurred by the tested fungicides compared with the tested herbicides. The percentages of the estimated nitrogen and protein content in common bean green seeds were increased due to the treatment with the tested herbicides and fungicides compared with the green seeds of plants grown in soil infested with any of both pathogens. The tested fungicides caused considerable increase in the percentages of total nitrogen and protein when compared to the tested herbicides.

Effect of Various Fertilizers on Stable Isotope Ratios and Relative Amino Acid Content in Apple Seeds

A modern, healthy diet relies on ever greater consumption of fruits, vegetables and other plant-based foods, with apples being some of the most affordable and readily available fruits that in most cases can be produced locally. With the higher interest of consumers in certified organic food products, methods for testing the food authenticity are becoming of key interest. For a food product to be labelled “organic”, it must be grown in certain conditions, without the use of pesticides, herbicides and synthetic fertilizers to elevate the yield. In this study the effect of different fertilizers on the nitrogen isotope ratios and amino acid composition in apples has been evaluated. Different parts of an apple were analyzed, and it was determined that only seeds contained enough nitrogen to give reliable results on δ15NAIR values and total nitrogen content. The results of apple seed analysis with stable isotope ratio mass spectrometry (SIRMS) showed that in three out of four apple varieties, the heavier nitrogen isotope (15N) content was higher in nitrogen-fertilized apples than in non-fertilized ones. Our research did not find any statistically significant correlation between the nitrogen and carbon content in apple seeds and the fertilization regime. The relative amino acid content in apple seeds was determined by gas chromatography and it was found that there is a moderate correlation between the stable nitrogen isotope ratios in apple seeds and the relative content of alanine and tryptophan.

Evaluation of growth, yield, oil content, irrigation water use efficiency of sunflower (Helianthus annuus L.) at different levels of plant density and nitrogen content

Iran has been facing shortage of edible oil and a rapid growing population, and the country has to supplement the needs by importing. To investigate the effect of planting densities and different amounts of some traits of sunflower, an experiment was conducted as a split plot in the form of randomized complete blocks design with three replicates in the research farm of the Agricultural and Natural Resources Research and Education Centre of Semnan province (Shahrood). Plant density in four levels (4, 6, 8 and 10 plant.m−2) as a main plot and the amount of nitrogen levels (0.50, 100, 150 and 200 kg N ha−1) as sub-plot were considered. Leaf greenness index, plant height, 100-seed weight, seed nitrogen content and seed oil content were significantly affected by the simple effect of planting density and decreased with increasing plan density. Also, the nitrogen levels significantly affected the studied traits, so that by increasing the amount of nitrogen application, from control to 200 kg N ha−1, the leaf greenness index increased by 15.3%. At a density of four plant.m−2 and an increase in nitrogen levels, water use efficiency increased along with an increase height and leaf area index, but higher levels of plant density led to smaller plant yield, less plant biomass and lower water efficiency. The highest nitrogen use efficiency was obtained at a density of 8 plant.m−2 and no application of nitrogen fertilizer. Finally, maximum seed yield (4016 kg.ha−1) and oil yield (1827 kg.ha−1) were obtained by applying 150 kg N ha−1 and density of 8 plants.m−2.

High-throughput screening of soybean di-nitrogen fixation and seed nitrogen content using spectral sensing

Symbiotic di-nitrogen fixation of grain legumes has a substantial impact on crop performance, harvest product quality, and nitrogen (N) balance of crop rotations, particularly under organic management regimes. In soybean breeding, selection for increased nitrogen fixation is desirable for improving seed protein content and N balance of cropping systems. However, the lack of high-throughput screening methods for direct measurement of N2 fixation rates prohibits practical breeding efforts. Therefore, hyperspectral canopy reflectance measurement as a field-based phenotyping method was evaluated in three environments for indirect estimation of N fixation and uptake of soil nitrogen in a set of early maturity soybean genotypes exhibiting a wide range in seed protein content. Reflectance spectra were collected in repeated measurements during flowering and early seed filling stages. Subsequently, various spectral reflectance indices (SRIs) were calculated for characterizing nitrogen accumulation of individual genotypes. Moreover, prediction models for seed protein content as an end-of-season target trait were developed utilizing full spectral information in partial-least-square regression (PLSR) models. A number of N-related SRIs calculated from spectral reflectance data recorded at the beginning of the seed filling stage were significantly correlated to seed protein content. The best prediction of seed protein content, however, was achieved in PLSR models (validation R2 = 0.805 across all three environments). Environments lower in initial soil mineral N content appeared as more favorable selection sites in terms of prediction accuracy, because N fixation is not masked by soil N uptake in such environments. Hyperspectral reflectance data proved to be a valuable method for determining genetic variation in crop N accumulation, which might be implemented in high-throughput screening protocols for N fixation in plant breeding programs.

MULTIVARIATE ANALYSIS OF GENETIC DIVERSITY AMONG THIRTY-SEVEN Chenopodium quinoa GENOTYPES UNDER ORGANIC AND MINERAL FERTILIZATION

Assessing the genetic diversity among quinoa germplasm is of prime importance for its effective utilization in breeding programs. The aims of the present investigation were to evaluate the magnitude of genetic diversity, based on phenotypic data, among 37 quinoa genotypes, under organic and/or inorganic fertilizer conditions and assess interrelationships between seed yield and its related traits under both environments. Two experiments were carried out in two seasons; the 1st experiment under organic fertilization and the 2nd under mineral fertilization conditions. A randomized complete blocks design with three replications was used. Principle component analysis (PCA) and GT-Biplot technique were used. Quinoa genotypes recorded significant differences (P≤0.01) for all studied traits under each environment. The promising genotype(s) for each trait were identified. Results of GT-biplot indicated that the traits, branches/plant, seed diameter, seed yield/plant, seed nitrogen content, biological yield/plant, 1000-seed weight, seed oil content, plant height, inflorescence diameter, inflorescences/plant and chlorophyll concentration index were strongly correlated with seed yield/ha, had high estimates of heritability and genetic advance and thus could be considered as secondary traits for high seed yield either under organic or inorganic fertilization. The clustering analysis assigned the 37 quinoa genotypes into three groups. The highest genetic dissimilarity Euclidean coefficients were recorded between G23 and each of G8, G34, G4, G9, G24 and G5; they are the most unrelated genotypes, but the lowest dissimilarity was between G13 and G26, they are the most related genotypes. The identified promising genotypes and secondary traits could be offered to quinoa breeders for use in future breeding programs to improve seed yield.

Effects of zeolite and biofertilizers on yield components, yield and nutrients uptake in grains of two corn cultivars (cv. 6010 and ns71)

In order to study the effects of zeolite and biofertilizers on yield components, yield and nutrients uptake in grains of two corn cultivars (cv. 6010 and ns71), a field experiment was conducted as split plot in a randomized complete block design with three replications at Neka, Mazandaran province, Iran in 2017 and 2018. The corn cultivars cv. 6010 and ns71 were the main plots and applications of zeolite and biofertilizers in 6 combinations including the zeolite application, Bacillus sp., arbuscular mycorrhizal fungi (AMF), applications of zeolite + Bacillus sp., applications of zeolite + AMF and applications of zeolite + Bacillus sp. + AMF were considered as sub-plots. The results showed that by applications of zeolite + Bacillus sp. + AMF, increased the yield components and seed yield of corn. The maximum seed yield (4.48 t ha−1) was obtained with simultaneous application of zeolite and biofertilizers, and the yield decreased with separate application of zeolite by 31.2%. Among two cultivars used in the experiment, the ns71 cultivar was superior to 6010 cultivar in terms of seed yield. The seed nitrogen content was significantly increased in both cultivars during the two cropping seasons by AMF application. The combined application of zeolite + Bacillus sp. + AMF resulted in the highest amount of seed phosphorus (0.3910 ppm) in the ns71 cultivar in the second year of experiment. Therefore, the combined application of zeolite and biofertilizers is recommended to increase the quantitative and qualitative yield of corn.

Association Study of Symbiotic Genes in Pea (Pisum sativum L.) Cultivars Grown in Symbiotic Conditions

In garden pea (Pisum sativum L.), several symbiotic genes are known to control the development of mutualistic symbioses with nodule bacteria (NB) and arbuscular mycorrhizal fungi (AMF). Here, we studied whether the allelic state of the symbiotic genes was associated with the growth parameters of pea plants under single inoculation with NB and under double inoculation with NB + AMF. Using different statistical methods, we analyzed the dataset obtained from a pot experiment that involved 99 pea cultivars, 10 of which were characterized as having shortened internodes due to the presence of the natural mutation p.A229T in the developmental gene Le. The plant’s habitus strongly influenced most of the studied growth and yield parameters and the effectiveness of the symbiotic interactions under NB and NB + AMF inoculation. Double inoculation had different effects on Le+ (normal) and le− (dwarf) plants with regard to nitrogen and phosphorus content in seeds. Regardless of the Le-status of plants, allelic states of the symbiotic gene LykX encoding the putative receptor of Nod factors (bacterial signal molecules) were shown to be associated with seed number, thousand-seed weight, and pod number at the level of FDR < 0.001, whereas associations of allelic states of the other studied symbiotic genes were less significant.

​Towards Quest for Early Maturing Mungbean [Vigna radiata (L.) Wilczek] Lines with Improved Nutritional Quality and High Yield

Background: Mungbean [Vigna radiata (L.) Wilczek], a rich source of protein, carbohydrate and different micronutrients, can play an important role in food security programmes. Enhancement of nutritional qualities via biofortification of existing varieties is a promising area of research. Methods: In the current study, sixty one mungbean were taken to study different biochemical parameters and also to establish an inter-relationship of each parameter with yield and maturity. Result: Results show that, nine lines, which included two germplasms namely, B1 and Pusa-9632 along with four mutants as well as three hybirds were found to have higher nutritional quality especially carbohydrate and protein content. Moreover, the mutants and segregants showed a higher nutritional value (% increase) than the germplasms. In addition, correlation coefficient study ensured an interrelationship between agronomic and biochemical characters by reporting that the total starch and nitrogen content of mungbean seeds can serve as an excellent selection marker for improving seed yield.

Plant DNA methylation is sensitive to parent seed N content and influences the growth of rice

BackgroundNitrogen (N) is an important nutrient for plant growth, development, and agricultural production. Nitrogen stress could induce epigenetic changes in plants. In our research, overexpression of the OsNAR2.1 line was used as a testing target in rice plants with high nitrogen-use efficiency to study the changes of rice methylation and growth in respond of the endogenous and external nitrogen stress.ResultsOur results showed that external N deficiency could decrease seed N content and plant growth of the overexpression line. During the filial growth, we found that the low parent seed nitrogen (LPSN) in the overexpression line could lead to a decrease in the filial seed nitrogen content, total plant nitrogen content, yield, and OsNAR2.1 expression (28, 35, 23, and 55%, respectively) compared with high parent seed nitrogen (HPSN) in high nitrogen external supply. However, such decreases were not observed in wild type. Furthermore, methylation sequencing results showed that LPSN caused massive gene methylation changes, which enriched in over 20 GO pathways in the filial overexpression line, and the expression of OsNAR2.1 in LPSN filial overexpression plants was significantly reduced compared to HPSN filial plants in high external N, which was not shown in wild type.ConclusionsWe suggest that the parent seed nitrogen content decreased induced DNA methylation changes at the epigenetic level and significantly decreased the expression of OsNAR2.1, resulting in a heritable phenotype of N deficiency over two generations of the overexpression line.

Genome-Wide Association Studies of Mineral Content in Common Bean.

Micronutrient malnutrition is one of the main public health problems in many parts of the world. This problem raises the attention of all valuable sources of micronutrients for the human diet, such as common bean (Phaseolus vulgaris L.). In this research, a panel of 174 accessions representing Croatian common bean landraces was phenotyped for seed content of eight nutrients (N, P, K, Ca, Mg, Fe, Zn, and Mn), and genotyped using 6,311 high-quality DArTseq-derived SNP markers. A genome-wide association study (GWAS) was then performed to identify new genetic sources for improving seed mineral content. Twenty-two quantitative trait nucleotides (QTN) associated with seed nitrogen content were discovered on chromosomes Pv01, Pv02, Pv03, Pv05, Pv07, Pv08, and Pv10. Five QTNs were associated with seed phosphorus content, four on chromosome Pv07, and one on Pv08. A single significant QTN was found for seed calcium content on chromosome Pv09 and for seed magnesium content on Pv08. Finally, two QTNs associated with seed zinc content were identified on Pv06 while no QTNs were found to be associated with seed potassium, iron, or manganese content. Our results demonstrate the utility of GWAS for understanding the genetic architecture of seed nutritional traits in common bean and have utility for future enrichment of seed with macro– and micronutrients through genomics-assisted breeding.

Effect of irrigation salinity and ecotype on the growth, physiological indicators and seed yield and quality of Salicornia europaea

The euhalophyte species Salicornia europaea is cultivated for oilseed and as a fodder crop in various parts of the world. In saline coastal environments it possesses great potential for the subsistence of the most disadvantaged farmers. We investigated the effect of salinity levels in irrigation water on the germination capacity, shoot biomass and seed productivity as well as diverse quality traits (nitrogen content in shoots and seeds and fatty acids, in seeds) and physiological traits (stable carbon and nitrogen isotopes and ion content) of two accessions collected in the United Arab Emirates (UAE). The three salinity levels tested were irrigation with fresh water (0.3 dS m−1), brackish water (25 dS m−1) and sea water (40 dS m−1). In addition, a hypersaline condition (80 dS m−1) was also tested for germination. The best germination rates were achieved with seeds exposed to fresh and brackish water, while imbibition with sea water decreased germination by half and hypersaline water inhibited it almost totally. However, the best irrigation regime in terms of biomass and seed yield involved brackish water. Moreover, rising salinity in the irrigation increased the stable isotope composition of carbon (δ13C) and nitrogen (δ15N), together with the Na+ and K+ of shoots and seeds, and the lipid levels of seeds, while the total nitrogen content and the profile of major fatty acids of seeds did not change. Differences between the two ecotypes existed for growth and seed yield with the best ecotype exhibiting lower δ13C and higher K+ in both shoots and seeds, lower Na+ and higher δ15N in shoots, and lower N in seeds, together with differences in major fatty acids. Physiological mechanisms behind the response to irrigation salinity and the ecotypic differences are discussed in terms of photosynthetic carbon and nitrogen metabolism.