Kernel Zn Research Articles

Genetic variability, correlation and cluster analysis of sub-tropical maize inbreds for morphological characteristics and kernel micronutrient contents

In the present study, forty eight sub-tropical maize inbreds were analyzed for grain yield and yield attributing traits along with micronutrients content. Genotypic differences were significant among the maize inbreds for all the traits under study. Kernel Fe concentration ranged from 14.23 to 38.08 mg/kg, while kernel Zn concentration varied from 11.61 to 39.41 mg/kg. Kernel copper (Cu) and manganese (Mn) content ranged from 1.34 to 4.31 mg/kg and 2.05 to 9.83 mg/kg, respectively. Significant positive correlation was observed among the kernel Fe, Zn, Cu and Mn, indicating the possibility of their simultaneous improvement. For kernel Fe concentration, GWL28 (38.08 mg/kg) and CML296 (33.78 mg/kg) were found to be the best genotypes. In case of Zn content, GWL28 (39.41 mg/kg) and GYL10 (35.41 mg/kg) were the best inbreds. Genetic diversity based on all the four micronutrients grouped 48 inbreds into five major clusters. The highest genetic dissimilarity was observed between CM133 and CML251, while CML251 and CML293 showed the lowest dissimilarity. Rank summation index identified CML296, GYL1 and CML269 as first three best inbreds for kernel micronutrients content and grain yield. The promising inbreds identified here would be useful for developing biofortified maize hybrids enriched with micronutrients

Improved agronomic biofortification of sweetcorn achieved using foliar rather than soil Zn applications

AbstractBackground and ObjectivesThis field and glasshouse study evaluates the relative effectiveness of agronomic zinc biofortification strategies to increase the Zn concentration in sweetcorn (Zea mays) kernels for human health, using applications of Zn fertilizer to the root‐zone or to foliage.FindingsPlants accumulated additional Zn as the rate of Zn applied to the root‐zone increased, but most was retained in the stems and foliage and little was translocated into the kernels (≤7%). A large proportion of the additional Zn stored in the foliage was in the form of Zn‐phytate. In contrast, in field‐grown plants where soil Zn was adequate for maximizing commercial yields, Zn applications to foliage increased kernel Zn concentrations by up to 100%. ZnSO4·7H2O was more effective to use in foliar applications compared with Zn‐EDTA.ConclusionThe elevated kernel concentrations recorded for two varieties (59.1 and 71.1 mg Zn kg−1) were greater than all previously reported biofortification responses from maize. These concentrations also matched or exceeded the HarvestPlus target of 60 mg Zn kg−1 for maize.Significance and NoveltyWith a total kernel Zn content of 3.6 mg Zn per cob, approximately 25%–45% of the recommended dietary Zn intake could be met with one cob of Zn‐biofortified sweetcorn.

Effects of phosphorus fertilizer on kernel phytic acid and zinc bioavailability in sweet corn

<p id="C3">To clarify the effects of phosphorus fertilizer on nutritional characteristics of sweet corn kernels, the temporal (different filling stages) and spatial (upper, middle, and lower cob; kernel skin dregs, endosperm and embryo) variations of phytic acid (PA), phosphorus (P) and zinc (Zn) contents and Zn bioavailability of sweet corn kernels and their responses to exogenous phosphorus fertilizer were investigated using filed phosphorus fertilizer experiment (P fertilizer location experiment for sweet corn genotypes and P fertilizer level experiment). The results were as follows: P fertilizer mainly inhibited Zn bioavailability by suppressing Zn concentration in sweet corn kernels, and increased PA concentrations concurrently. P fertilizer input showed significant effects on the accumulation of PA, P, and Zn (mg plant^-1) after 16-24 days of silking, while inhibitory effects were detected on Zn bioavailability at different kernel filling stages. There was no significant difference in the kernel of PA (g kg^-1) and zinc bioavailability among different cob positions under medium P treatment. However, the high P level significantly improved the accumulation of PA in the middle and lower cob, while the inhibitory effect was found on the kernel of Zn concentration and Zn bioavailability at all cob positions. Among different parts of the kernel (skin dregs, endosperm, and embryo), the concentrations of PA, P, and Zn were the highest values in the embryo and their accumulation were the highest value in the endosperm, while Zn bioavailability was also the highest in the embryo. High P treatment significantly increased PA and P concentrations and decreased Zn concentration and its bioavailability at different kernel positions. Hence, optimized phosphorus fertilizer application could promote kernel Zn accumulation, while excessive P fertilizer input significantly increased PA accumulation at different filling stages, as well as in the endosperm and embryo, and eventually had a significant inhibitory effect on kernel Zn bioavailability in sweet corn at different cob and kernel positions. This study provides a theoretical reference for the biofortification of Zn in sweet corn seeds.

Elevated zinc concentration in zeaxanthin-biofortified sweetcorn kernels compared with a commercial hybrid

A glasshouse experiment was conducted to assess the potential for increasing sweetcorn (Zea mays L. var. rugosa) kernel zinc (Zn) concentration. Uptake of Zn was compared between a standard commercial supersweet variety ‘Hybrix 5’ and a zeaxanthin-biofortified variety ‘High zeaxanthin 103146’. The plants were grown in potted soil culture using a Vertisol soil, and five rates of Zn (0, 0.75, 1.5, 3 and 6 kg Zn ha‑1) applied as ZnSO4.7H2O. Cobs were harvested at the appropriate maturity for sweetcorn eating, three weeks after pollination. On a fresh weight (FW) basis, the kernel Zn concentration in ‘High zeaxanthin 103146’ (7.11±0.21 mg Zn kg‑1) was ca. three times that of ‘Hybrix 5’ (2.57±0.20 mg Zn kg‑1) (p<0.001). The higher Zn concentration of ‘High zeaxanthin 103146’ was also significant in other plants parts, although not to the same extent as in kernel concentration. There was no effect of soil Zn fertilisation within the range of concentrations tested on increasing tissue Zn concentration of any plant part. Interestingly, the pollination of ‘High zeaxanthin 103146’ was generally poorer than ‘Hybrix 5’, resulting in lower kernel numbers per cob. Pollination differences may have contributed to the higher Zn concentration in ’High zeaxanthin 103146’ by reducing inter-kernel competition for Zn transported into the cob. The results show that sweetcorn kernels can potentially accumulate higher Zn concentrations and sweetcorn may be a useful target crop for Zn biofortification, while the lack of a soil Zn fertilisation effect suggests that genetic biofortification may be more effective in achieving elevated Zn concentrations in sweetcorn kernels.

Genomic Prediction with Genotype by Environment Interaction Analysis for Kernel Zinc Concentration in Tropical Maize Germplasm.

Zinc (Zn) deficiency is a major risk factor for human health, affecting about 30% of the world’s population. To study the potential of genomic selection (GS) for maize with increased Zn concentration, an association panel and two doubled haploid (DH) populations were evaluated in three environments. Three genomic prediction models, M (M1: Environment + Line, M2: Environment + Line + Genomic, and M3: Environment + Line + Genomic + Genomic x Environment) incorporating main effects (lines and genomic) and the interaction between genomic and environment (G x E) were assessed to estimate the prediction ability (rMP) for each model. Two distinct cross-validation (CV) schemes simulating two genomic prediction breeding scenarios were used. CV1 predicts the performance of newly developed lines, whereas CV2 predicts the performance of lines tested in sparse multi-location trials. Predictions for Zn in CV1 ranged from -0.01 to 0.56 for DH1, 0.04 to 0.50 for DH2 and -0.001 to 0.47 for the association panel. For CV2, rMP values ranged from 0.67 to 0.71 for DH1, 0.40 to 0.56 for DH2 and 0.64 to 0.72 for the association panel. The genomic prediction model which included G x E had the highest average rMP for both CV1 (0.39 and 0.44) and CV2 (0.71 and 0.51) for the association panel and DH2 population, respectively. These results suggest that GS has potential to accelerate breeding for enhanced kernel Zn concentration by facilitating selection of superior genotypes.

Zinc biofortification of immature maize and sweetcorn (Zea mays L.) kernels for human health

This study explores the potential for genetic biofortification of sweetcorn (Zea mays L.) by quantifying immature kernel zinc (Zn) concentrations across a broad range of Zea mays L. germplasm. Varieties examined included commercial sweetcorn cultivars, high zeaxanthin sweetcorns, purple sweetcorns, blue maize, quality protein maize and popcorns. Though all kernel samples were harvested at a physiologically immature stage typical of sweetcorn harvest and consumption (21 days after pollination, DAP), the varieties accumulated distinctly different kernel dry matter concentrations depending on whether they were classified as sugary or starchy varieties. The difference in dry matter concentration between types confounded comparisons of kernel Zn concentration when assessed on a fresh mass basis, which is typically used to quantify dietary intake. Kernel mass (indicative of kernel size) and the ratio of embryo-to-kernel mass also contributed to variation in kernel Zn concentration. Analysis of a broader range of nutrient concentrations suggested that variation in kernel Zn concentration was more closely associated with variations in S concentration than P concentration in the sugary varieties. This suggested the possibility of biofortifying sweetcorn kernel Zn without necessarily increasing kernel P and associated anti-nutrient compounds like phytate.

Transcriptional dynamics of Zn-accumulation in developing kernels of maize reveals important Zn-uptake mechanisms

In the present study, transcriptomic analysis of 10-days old baby kernels of two contrasting maize genotypes, namely VQL-2 (high kernel Zn accumulator) and CM-145 (low kernel Zn accumulator), under low- and optimum- soil Zn conditions generated 1948 differentially expressed transcripts. Among these, 666 and 437 transcripts were up-regulated and down-regulated respectively in VQL-2; whereas, 437 and 408 transcripts were up-regulated and down-regulated respectively in CM-145. Remarkably, 135 transcription factors and 77 known Zn transporters expressed differentially. By comparing the transcripts differentially expressed between the optimum-Zn and low-Zn libraries of the contrasting genotypes, we identified 21,986 and 26,871 SNPs, respectively. Similarly, 6810 and 8192 InDels were found between optimum- and low-Zn growing conditions, respectively. Further, 21 differentially expressed genes were co-localized with already known QTLs associated with Zn uptake, such as qZn10, CQZnK9–1 and YNZnK6. These findings will be useful to develop high Zn-accumulator maize through marker-assisted breeding in future.

Variation in zinc concentration of sweetcorn kernels reflects source-sink dynamics influenced by kernel number.

Grain yield and mineral nutrient concentration in cereal crops are usually inversely correlated, undermining biofortification efforts. Here, sink size, expressed as kernel number per cob, was manipulated by controlling the time when the silks of sweetcorn (Zea mays) cv. Hybrix 5 and var. HiZeax 103146 were exposed to pollen. Twelve other varieties were manually pollinated to achieve the maximum potential kernel number per cob, and kernel Zn concentration was correlated with kernel number and kernel mass. As kernel number increased, kernel Zn concentration decreased, with the decrease occurring to similar extents in the embryo tissue and the rest of the kernel. However, total kernel Zn accumulated per cob increased with increasing kernel number, as the small decreases in individual kernel Zn concentration were more than offset by increases in kernel number. When both kernel number and mass were considered, 90% of the variation in kernel Zn concentration was accounted for. Differential distribution of assimilates and Zn to sweetcorn cobs led to significant decreases in kernel Zn concentration with increasing kernel number. This suggests there will be challenges to achieving high kernel Zn concentrations in modern high-yielding sweetcorn varieties unless genotypes with higher Zn translocation rates into kernels can be identified.

Survey of aflatoxin B1 and heavy metal contamination in peanut and peanut soil in China during 2017–2018

Peanut, as a nutritious, healthy and delicious food, is susceptible to contamination by aflatoxin B1 (AFB1) and heavy metals, which has an adverse impact on the healthy development of peanut industry in China. This research was to evaluate the contamination of AFB1 and heavy metals (cadmium, chromium, lead, tin, copper and zinc) in peanut, to analyze the difference of AFB1 and heavy metal contamination in peanut in the four main peanut producing regions (Northeast area, Yellow River basin, Yangtze River basin and Southeast coast), and to analyze and discuss the difference of heavy metal content in peanut kernel, peanut shell and peanut soil. The results showed that the mean concentration of AFB1 in peanut was 1.08 μg/kg, and the detection rate of AFB1 was 33.80%. There was no significant difference in AFB1 contamination of peanut between 2017 and 2018. The most serious AFB1 contamination region was the Yangtze River basin, followed by the Southeast coast, the Yellow River basin and the Northeast area. The average levels of cadmium (Cd), chromium (Cr), lead (Pb), tin (Sn), copper (Cu) and zinc (Zn) in peanut kernel were 0.18, 0.44, 0.03, 0.01, 9.24 and 31.42 mg/kg, respectively. There was a significant difference in the mean content of heavy metals (Cr, Sn, Cu and Zn) in peanut kernels between 2017 and 2018. The mean content of Cd in peanut kernel was the highest in Northeast area, and there was no significant difference in the mean content of Pb in the four main peanut producing regions. The average concentration of other heavy metals (Cr, Sn, Cu and Zn) in peanut kernel in south of China (Yangtze River basin and Southeast coast) was higher than that in north of China (Northeast area and Yellow River basin). Due to the different bio-accumulation ability of peanut kernel and peanut shell to different heavy metal, the average levels of heavy metals in peanut kernel and peanut shell were different. The ability of peanut kernel to bio-accumulate Cd, Cu and Zn was stronger than that of peanut shell, and the ability of bio-accumulate of Cr, Pb and Sn was weaker than peanut shell. There was a significant positive correlation between heavy metal pollution of peanut and heavy metal content in soil. In conclusion, the situation of AFB1 and heavy metal contamination in peanut in China was not optimistic, and the pollution of peanut in south of China was more serious than that in north of China. Therefore, the control and prevention of AFB1 and heavy metal in peanut should be strengthened.

Genomic Prediction of Kernel Zinc Concentration in Multiple Maize Populations Using Genotyping-by-Sequencing and Repeat Amplification Sequencing Markers

Enriching of kernel zinc (Zn) concentration in maize is one of the most effective ways to solve the problem of Zn deficiency in low and middle income countries where maize is the major staple food, and 17% of the global population is affected with Zn deficiency. Genomic selection (GS) has shown to be an effective approach to accelerate genetic gains in plant breeding. In the present study, an association-mapping panel and two maize double-haploid (DH) populations, both genotyped with genotyping-by-sequencing (GBS) and repeat amplification sequencing (rAmpSeq) markers, were used to estimate the genomic prediction accuracy of kernel Zn concentration in maize. Results showed that the prediction accuracy of two DH populations was higher than that of the association mapping population using the same set of markers. The prediction accuracy estimated with the GBS markers was significantly higher than that estimated with the rAmpSeq markers in the same population. The maximum prediction accuracy with minimum standard error was observed when half of the genotypes were included in the training set and 3,000 and 500 markers were used for prediction in the association mapping panel and the DH populations, respectively. Appropriate levels of minor allele frequency and missing rate should be considered and selected to achieve good prediction accuracy and reduce the computation burden by balancing the number of markers and marker quality. Training set development with broad phenotypic variation is possible to improve prediction accuracy. The transferability of the GS models across populations was assessed, the prediction accuracies in a few pairwise populations were above or close to 0.20, which indicates the prediction accuracies across years and populations have to be assessed in a larger breeding dataset with closer relationship between the training and prediction sets in further studies. GS outperformed MAS (marker-assisted-selection) on predicting the kernel Zn concentration in maize, the decision of a breeding strategy to implement GS individually or to implement MAS and GS stepwise for improving kernel Zn concentration in maize requires further research. Results of this study provide valuable information for understanding how to implement GS for improving kernel Zn concentration in maize.

Comparison of Zn accumulation and speciation in kernels of sweetcorn and maize differing in maturity.

Understanding the speciation of Zn in edible portions of crops helps identify the most effective biofortification strategies to increase the supply of nutrients for improving the health and nutrition of consumers. Kernels of 12 sweetcorn and three maize (Zea mays) varieties were analysed for Zn concentration and content. The speciation of the Zn in the embryos, endosperms and whole kernels at 21, 28 and 56 days after pollination (DAP) was then examined for one maize and one sweetcorn variety using synchrotron-based X-ray absorption spectroscopy (XAS). Averaged across all sweetcorn and maize varieties at 21 DAP, the embryo contributed 27-29% of the whole kernel Zn whilst the endosperm contributed 71-73 %. While sweetcorn embryos contributed a lower proportion to the total kernel Zn than those of maize, the proportion of total Zn in the embryo increased as kernels aged for both varieties, reaching 33 % for sweetcorn and 49% for maize at 28 DAP. Using XAS, it was predicted that an average of 90 % of the Zn in the embryos was present as Zn-phytate, while in the endosperm the Zn was primarily complexed with an N-containing ligand such as histidine and to a lesser extent with phytate. However, in maize endosperms, it was also observed that the proportion of Zn present as Zn-phytate increased as the kernel matured, thereby also probably decreasing its bioavailability in these mature maize kernels. The apparent low bioavailability of Zn supplied in maize at its consumption stage (i.e. mature kernels) probably undermines the effectiveness of biofortification of this crop. Conversely, successful biofortification of Zn in sweetcorn and green maize consumed as immature kernels could potentially provide a good source of bioavailable Zn in human diets.

Speciation and accumulation of Zn in sweetcorn kernels for genetic and agronomic biofortification programs.

In sweetcorn (Zea mays L.), embryo Zn is accumulated mainly as Zn-phytate, whereas endosperm Zn is complexed with a N- or S-containing ligand. Understanding the speciation of Zn in crop plants helps improve the effectiveness of biofortification efforts. Kernels of four sweetcorn (Zea mays L.) varieties were analysed for Zn concentration and content. We also assessed the speciation of the Zn in the embryo, endosperm, and pericarp in situ using synchrotron-based X-ray absorption spectroscopy. The majority of the Zn was in the endosperm and pericarp (72%), with the embryo contributing 28%. Approximately 79% of the Zn in the embryo accumulated as Zn-phytate, whereas in the endosperm most of the Zn was complexed with a N- or S-containing ligand, possibly as Zn-histidine and Zn-cysteine. This suggests that whilst the Zn in the endosperm and pericarp is likely to be bioavailable for humans, the Zn in the embryo is of low bioavailability. This study highlights the importance of targeting the endosperm of sweetcorn kernels as the tissue for increasing bioavailable Zn concentration.

Zinc biofortification of maize (Zea mays L.): Status and challenges

AbstractZn deficiency is one of the leading health problems in children and women of developing countries. Different interventions could be used to overcome malnutrition, but biofortification is most impactful, convenient, sustainable and acceptable intervention. Maize is one of the major crops grown and consumed in the regions with prevalent Zn malnutrition; therefore, this is suitable target for Zn biofortification. Zn biofortification of maize could be achieved through agronomic and genetic approaches. Discussion of agronomic approaches with genetic approaches is prerequisite because soils in developing countries are deficit of Zn and availability of Zn in soils is mandatory for estimating the genetic responses of maize genotypes through genetic approaches. Seed priming, foliar and soil applications are agronomic tools for biofortification, but solo and combined applications of these treatments have different effects on Zn enrichment. Genetic approaches include the increase of Zn bioavailability or increase of kernel Zn concentration. Zn bioavailability could be increased by reducing the anti‐nutritional factors or by increasing the bioavailability enhancers. Kernel Zn concentration could be improved through hybridization and selections, whereas genetically engineered attempts for improving Zn uptake from soil, loading in xylem, remobilization in grains and sequestration in endosperm can further improve the kernel Zn concentration. Key challenges associated with dissemination of Zn biofortified maize are also under discussion in this draft. Current review emphasized all of above‐mentioned contents to provide roadmap for the development of Zn biofortified maize genotypes to curb the global Zn malnutrition.

Effects of long-term fertilizer applications on peanut yield and quality and plant and soil heavy metal accumulation

The status of essential and potentially toxic trace elements in soils and crops can be affected by long-term fertilization practices. This study aimed to investigate changes in peanut (Arachis hypogaea L.) yield and kernel quality, and changes in copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) concentrations in soil and peanut kernels after 16 years of continuous cropping with different fertilization treatments. Five fertilization treatments were applied at a red soil site in Southeast China: chemical fertilizer (F) containing nitrogen, phosphorus, and potassium, F + trace elements (FT), pig manure (M), M + effective microorganisms (MB), and MB + trace elements (MBT). Properties of soil and pig manure, heavy metal contents in soil and peanut kernels, and the compositions of amino and fatty acids in kernels were determined. Application of pig manure significantly increased peanut biomass, kernel yield, and crude protein and total amino acid contents in kernels, but led to higher amounts of Cu, Zn, and Cd in soil and higher amounts of Zn and Cd in peanut kernels compared with that of chemical fertilizer. There should be greater concern about potential kernel Cd and Zn contaminations resulting from long-term application of pig manure contaminated with potentially toxic metals as an organic fertilizer.

Row and Forage Crop Rotation Effects on Maize Mineral Nutrition and Yield

Diverse crop rotations are an integral component of sustainable agriculture. The objectives were to investigate row and forage crop rotation effects on stover biomass, grain yield, and mineral nutrient concentrations of maize (Zea mays L.) grown under a maize–soybean [Glycine max (L.) Merr.] 2-yr rotation (C–S); maize–soybean–spring wheat (Triticum aestivum L.) 3-yr rotation (C–S–W); maize–soybean–oat/pea (Avena sativa L./Pisum sativum L.) hay 3-yr rotation (C–S–H); and maize–soybean–oat/pea hay underseeded with alfalfa (Medicago sativa L.) – alfalfa – alfalfa 5-yr rotation (C–S–H/A–A–A). Rotations were established in 1997 and maize plots were sampled in 2008–2011. Across the 4 yr of the study, grain yield was 10% greater (1.0 Mg ha−1) in C–S–H/A–A–A and C–S–W rotations compared with C–S with C–S–H intermediate. Under C–S–H/A–A–A, kernel N concentration was 7% greater, kernel P was 17% less, and kernel K was 7% less compared with C–S–W. Kernel Zn concentration was 16% lower in C–S–H than in C–S and C–S–H/...

Genotypic variability and inheritance of iron, phosphorus, potassium and zinc contents in segregating generations of peanut (Arachis hypogaea L.)

Micronutrient malnutrition is a serious health issue affecting billions of people in developing countries. Peanut is rich in several mineral elements required for human nutrition. The objective of this study was to understand genetic variability and inheritance pattern of phosphorus (P), potash (K), zinc (Zn) and iron (Fe) concentrations in F2 and F3 generations of two peanut crosses namely Girnar-3 × FDRS-10 (Cross-A) and TG-37A × FDRS-10 (Cross-B). Pshell, Znshell, Kshell, Feshell, and Fekernel were positively skewed indicating additive gene action. Kurtosis formost of the characters moved in positive direction from F2 to F3 generation indicating a reduction in variation as generation advances.Phenotypic coefficient of variance (PCV) and genotypic coefficient of variance (GCV) revealed that traits were under genetic control and possessed substantial variability and hence a good scope for improving these characters. Both additive and non-additive types of gene actions were observed with the predominance of additive gene action for the inheritance of P, K, Fe and Zn in shell and kernels. Dominance variance (H) also played an important role in the inheritance of P, K, Fe and Zn in peanut. Average degree of dominance for most of the traits was greaterthan unityindicating over dominance forthese traits. Mineral elements had significant association among themselves but very few associations with pod yield. Selection and hybridization followed by pedigree breeding method are suggested in the later generations for genetic improvement to identify high yielding peanut genotypes rich in P, K, Fe and Zn.

Soil Attributes, Soybean Mineral Nutrition, and Yield in Diverse Crop Rotations under No‐Till Conditions

Development of sustainable crop rotations depends on understanding complex relationships among soils, crops, and yield. Our objectives were to measure how soil chemical and physical attributes as well as soybean [Glycine max (L.) Merr.] stover dry weight and mineral concentrations, seed yield, and seed composition (protein, oil, and minerals) responded to a soybean–maize (Zea mays L.) 2‐yr rotation (S‐C), soybean–spring wheat (Triticum aestivum L.)–maize 3‐yr rotation (S‐W‐C), soybean–oat/pea (Hordeum vulgare L./Pisum sativum L.) hay–maize 3‐yr rotation (S‐H‐C), and soybean–oat/pea hay underseeded with alfalfa (Medicago sativa L.)–alfalfa–alfalfa–maize 5‐yr rotation (S‐H/A‐A‐A‐C). Rotation treatments under no‐till soil management were established in 1997 and soybean measurements were made during the 2009 and 2010 growing seasons. Soils under the 5‐yr rotation had 129 kg ha–1 preseason residual NO3–N concentration, while the other rotations averaged about 65 kg ha–1. The 5‐yr rotation also had lower bulk density (1.35 g cm–3) than S‐H‐C (1.46 g cm–3), with S‐W‐C (1.38 g cm–3) and S‐C (1.38 g cm–3) intermediate. Soybean seed yield was about 10% greater in the 5‐yr rotation than in the other treatments. Kernel protein was 3% greater and kernel Zn was 11% greater under the 5‐yr rotation than under the S‐C rotation, while the others were intermediate. Changes in soil physical and chemical properties under extended rotations that include perennial forages may play an important role in increasing soybean seed yield and enhancing seed protein but may, because of high preseason soil NO3–N levels, also be susceptible to potential NO3–N leaching beyond the root zone.

Bioaccessibility of Cd, Cu, Fe, Mn, Pb, and Zn in Hazelnut and Walnut Kernels Investigated by an Enzymolysis Approach

Bioaccessibility of four essential (Fe, Cu, Mn, Zn) and two toxic (Cd, Pb) elements in kernels of four walnut and four hazelnut cultivars was investigated using sequential enzymolysis approach and atomic absorption spectrometry. It was found that the assimilable part of elements was not dependent on nut cultivar. The bioaccessible fraction of Cu, Mn, and Zn was definitely higher for hazelnuts (62% Cu, 39% Mn, 58% Zn) than for walnuts (14% Cu, 21% Mn, 15% Zn). Bioaccessible Fe was 20-24% from its total content for both nut types. Solubility in the simulated intestinal juice is affected by both formation of stable soluble complexes and back sorption of dissolved elements on nut solid residues. Lead shows strong insolubility due to the high sorption affinity of lead ions to the insoluble fraction of nuts. Thus, walnuts and hazelnuts could act as effective biosorbents for lead detoxication.

Influence of parental forms on changes in the content of mineral elements in grain of new winter triticale hybrid strains

The paper presents a study on the content of Ca, Mg, K, Mn, Zn, Cu, and Fe in kernels (F5 generation) of winter triticale produced by crossbreeding three maternal with two paternal forms. As maternal forms, two strains were used, IGS 5101, FDT 975, as well as cultivar Alzo. The paternal components consisted of strains LAD 122 and F 8063. Morphologically established hybrid strains were selected at the Institute of Genetics, Plant Breeding and Biotechnology of the University of Life Sciences in Lublin. The component selection for crossbreeding was performed to achieve hybrids with great yield-forming potential and to improve the resistance to grain sprouting. Minerals were determined by the atomic absorption spectrometry (AAS) method. The results revealed differentiation in amounts of the analysed mineral components in hybrids depending on genotypes of the parental forms. Hybrid strains were usually characterized by a lower ash content in kernels than the parental forms. Among all the hybrids, strain IGS 5101 × F 8063 was distinguishable by its higher content of K, Ca, Mn, and Fe in grain versus both parental forms. It also excelled exceeded the other hybrids in respect of Ca, K and Mn. Tests on the mineral components in hybrid triticale strains indicate that it is possible to shape their levels through an appropriate selection of parental forms and selection during breeding work on X Triticosecale Wittmack genus to achieve cultivars of improved nutritional value.

Identification of kernel iron- and zinc-rich maize inbreds and analysis of genetic diversity using microsatellite markers

Development of micronutrient enriched staple foods is an important breeding goal in view of the extensive problem of ‘hidden hunger’ caused by micronutrient malnutrition. In the present study, kernel iron (Fe) and zinc (Zn) concentrations were evaluated in a set of 31 diverse maize inbred lines in three trials at two locations – Delhi (Kharif 2007 & 2008) and Hyderabad (Rabi 2007–08). The ranges of kernel Fe and Zn concentrations were 13.95–39.31 mg/kg and 21.85–40.91 mg/kg, respectively, across the three environments. Pooled analysis revealed significant genotype × environment (G × E) interaction in the expression of both the micronutrient traits, although kernel Fe was found to be more sensitive to G × E as compared to kernel Zn. Seven inbred lines, viz., BAJIM-06-03, DQPM-6, CM212, BAJIM-06-12, DQPM-7, DQPM-2 and CM129, were found to be the most stable and promising inbred lines for kernel Zn concentration, while for kernel Fe concentration, no promising and stable genotypes could be identified. Analysis of molecular diversity in 24 selected inbred lines with phenotypic contrast for the two kernel micronutrient traits, using 50 SSR markers covering the maize genome, revealed high levels of polymorphisms (214 SSR alleles; mean PIC value = 0.62). The phenotypically contrasting and genetically diverse maize inbred lines identified in this study could be potentially utilized in further studies on QTL analysis of kernel micronutrient traits in maize, and the stable and most promising kernel micronutrient-rich maize genotypes provide a good foundation for developing micronutrient-enriched maize varieties suitable for the Indian context.