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Tim J. O'hare - One of the best experts on this subject based on the ideXlab platform.
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Temperature and Maturity Stages Affect Anthocyanin Development and Phenolic and Sugar Content of Purple-Pericarp Supersweet Sweetcorn during Storage.
Journal of agricultural and food chemistry, 2021Co-Authors: Hung T. Hong, A. D. T. Phan, Tim J. O'hareAbstract:Purple-pericarp Sweetcorn (PPS) is a novel product, requiring both purple pigment development and maintenance of sweetness. Storage period and temperature had a profound impact on total anthocyanin accumulation (TAC) and sugar content. While TAC remained relatively unchanged during 14-day storage at 4 °C, the first recorded observation of continuing accumulation of anthocyanin and phenolic compounds was concurrent with an increase in purple pigment coverage across the surface of the kernel at 23 °C. TAC in PPS significantly increased, doubling after 14 days at 23 °C. Anthocyanin concentration and kernel coverage were also affected by harvest maturity. The results indicated that biosynthesis of anthocyanins is still occurring during postharvest storage of PPS. A significant decline in sugar concentration was also observed during storage with a greater decline at 23 °C. As anthocyanin accumulation and maintaining sweetness are important factors for Sweetcorn, identifying storage temperatures that optimize both quality criteria are required.
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Variation in zinc concentration of Sweetcorn kernels reflects source-sink dynamics influenced by kernel number.
Journal of experimental botany, 2020Co-Authors: Zhong Xiang Cheah, Tim J. O'hare, Stephen Harper, Michael J. BellAbstract:Grain yield and mineral nutrient concentration in cereal crops are usually inversely correlated, undermining biofortification efforts. 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 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 that decrease occurring to similar extents in both the embryo tissue and 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 responses in assimilate and Zn distribution 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.
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A dataset for anthocyanin analysis in purple-pericarp Sweetcorn kernels by LC-DAD-MS.
Data in brief, 2020Co-Authors: Hung T. Hong, Michael Netzel, Tim J. O'hareAbstract:Abstract This dataset refers to the accompanying article “Optimization of extraction procedure and development of LC-DAD-MS methodology for anthocyanin analysis in anthocyanin-pigmented corn kernels”, published in Food Chemistry [1]. Here, we present concentrations, profiles, MS2 spectra of individual anthocyanins (including isomers of cyanidin-3-(6’’-malonylglucoside)) of purple-pericarp Sweetcorn (PPS) kernels. Furthermore, an additional mass spectrum of an artefact-anthocyanin produced in acidified extraction solutions were reported. This data is further discussed in the accompanying research article [1]. Delphinidin-3-glucoside was used as an internal standard to compensate for individual anthocyanin losses during extraction with acidified solutions. The generated data could be used for anthocyanin identification and quantification in different anthocyanin-containing plant matrices.
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Super-Sweet Purple Sweetcorn: Breaking the Genetic Link
Proceedings, 2020Co-Authors: Apurba Anirban, Tim J. O'hareAbstract:Purple-pericarp supersweet Sweetcorn currently does not exist as a horticultural product. Purple pericarp comprises the outer layers of the kernel, with the purple pigment being produced by anthocyanin. Unlike the aleurone layer which can also be pigmented, the pericarp is maternal tissue. Although standard purple Sweetcorn based on mutations such as sugary1 (su1) and sugary enhancer (se1) are in existence, the development of purple supersweet Sweetcorn based on the widely used shrunken2 (sh2) gene mutation is much more challenging. This is because there is an extremely close genetic linkage between the supersweet shrunken-2 mutation and the anthocyanin biosynthesis gene, anthocyaninless-1 (a1). As distance between these two genes is only 0.1 cM, the development of purple supersweet Sweetcorn depends on breaking this close genetic link, which occurs at a very low frequency of 1 in 1000 meiotic crossovers. To make this possible, we crossed a white supersweet variety (a1a1sh2sh2) with a purple-pericarp Peruvian maize (A1A1Sh2Sh2) to obtain an initial heterozygous hybrid (A1a1Sh2sh2). The hybrid seed was sown and subsequently self-pollinated to produce seed segregating for the double recessive homozygote, sh2sh2 (1 in 4). These kernels present a visually distinctive phenotype, characterised by the seed’s shrunken appearance. Approximately 2760 sh2sh2 seeds were separated and resown. Due to the low frequency of linkage breakage, the majority of these plants (~99.9%) produced supersweet white cobs (a1a1sh2sh2). Three plants (0.1%) however, produced supersweet purple cobs (A1a1sh2sh2), due to a single low-frequency linkage break. These cobs will form the basis for a purple-pericarp supersweet Sweetcorn breeding program.
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Optimisation of extraction procedure and development of LC-DAD-MS methodology for anthocyanin analysis in anthocyanin-pigmented corn kernels.
Food chemistry, 2020Co-Authors: Hung T. Hong, Michael Netzel, Tim J. O'hareAbstract:Abstract An ultra-high-performance liquid chromatography–diode array detector–mass spectrometry method was developed for characterisation and quantification of anthocyanin components in complex corn-kernel matrices. The anthocyanin profiles and total anthocyanin content (TAC) of mature seeds of five types of anthocyanin-pigmented corn were reported. Internal standard was used to validate the efficiency of extraction and optimise the liquid extraction procedure for anthocyanins. A total of eighteen anthocyanins were identified and quantified. Cyanidin-based glucosides were the major pigments of purple-pericarp Sweetcorn (75.5% of TAC) and blue-aleurone maize (91.6%), while pelargonidin-based glucosides composed the main anthocyanins of reddish-purple-pericarp Sweetcorn (61.1%) and cherry-aleurone maize (74.6%). Importantly, previous studies reported the presence of acetylated and succinylated anthocyanins in corn kernels; these compounds were found to be artefact pigments, generated during the extraction process. These crucial findings provide the correct anthocyanin profiles of pigmented corns, and emphasise the importance of using acidified solutions for the extraction of corn-based anthocyanins.
Michael J. Bell - One of the best experts on this subject based on the ideXlab platform.
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elevated zinc concentration in zeaxanthin biofortified Sweetcorn kernels compared with a commercial hybrid
Acta Horticulturae, 2020Co-Authors: Zhong Xiang Cheah, Stephen Harper, T J Ohare, Michael J. BellAbstract: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.
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Variation in zinc concentration of Sweetcorn kernels reflects source-sink dynamics influenced by kernel number.
Journal of experimental botany, 2020Co-Authors: Zhong Xiang Cheah, Tim J. O'hare, Stephen Harper, Michael J. BellAbstract:Grain yield and mineral nutrient concentration in cereal crops are usually inversely correlated, undermining biofortification efforts. 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 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 that decrease occurring to similar extents in both the embryo tissue and 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 responses in assimilate and Zn distribution 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.
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Zinc biofortification of immature maize and Sweetcorn (Zea mays L.) kernels for human health
Scientia Horticulturae, 2020Co-Authors: Zhong Xiang Cheah, Tim J. O'hare, Stephen Harper, Jitka Kochanek, Michael J. BellAbstract: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.
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Elevated zinc concentration in zeaxanthin-biofortified Sweetcorn kernels compared with a commercial hybrid
Acta Horticulturae, 2020Co-Authors: Zhong Xiang Cheah, Tim J. O'hare, Stephen Harper, Michael J. BellAbstract: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
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Comparison of Zn accumulation and speciation in kernels of Sweetcorn and maize differing in maturity.
Annals of botany, 2019Co-Authors: Zhong Xiang Cheah, Peter M. Kopittke, Kirk G. Scheckel, Matthew R Noerpel, Michael J. BellAbstract:BACKGROUND AND AIMS: 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. METHODS: 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). KEY RESULTS: 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. CONCLUSIONS: 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.
Zhong Xiang Cheah - One of the best experts on this subject based on the ideXlab platform.
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elevated zinc concentration in zeaxanthin biofortified Sweetcorn kernels compared with a commercial hybrid
Acta Horticulturae, 2020Co-Authors: Zhong Xiang Cheah, Stephen Harper, T J Ohare, Michael J. BellAbstract: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.
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Variation in zinc concentration of Sweetcorn kernels reflects source-sink dynamics influenced by kernel number.
Journal of experimental botany, 2020Co-Authors: Zhong Xiang Cheah, Tim J. O'hare, Stephen Harper, Michael J. BellAbstract:Grain yield and mineral nutrient concentration in cereal crops are usually inversely correlated, undermining biofortification efforts. 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 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 that decrease occurring to similar extents in both the embryo tissue and 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 responses in assimilate and Zn distribution 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.
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Zinc biofortification of immature maize and Sweetcorn (Zea mays L.) kernels for human health
Scientia Horticulturae, 2020Co-Authors: Zhong Xiang Cheah, Tim J. O'hare, Stephen Harper, Jitka Kochanek, Michael J. BellAbstract: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.
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Elevated zinc concentration in zeaxanthin-biofortified Sweetcorn kernels compared with a commercial hybrid
Acta Horticulturae, 2020Co-Authors: Zhong Xiang Cheah, Tim J. O'hare, Stephen Harper, Michael J. BellAbstract: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
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Comparison of Zn accumulation and speciation in kernels of Sweetcorn and maize differing in maturity.
Annals of botany, 2019Co-Authors: Zhong Xiang Cheah, Peter M. Kopittke, Kirk G. Scheckel, Matthew R Noerpel, Michael J. BellAbstract:BACKGROUND AND AIMS: 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. METHODS: 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). KEY RESULTS: 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. CONCLUSIONS: 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.
Stephen Harper - One of the best experts on this subject based on the ideXlab platform.
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elevated zinc concentration in zeaxanthin biofortified Sweetcorn kernels compared with a commercial hybrid
Acta Horticulturae, 2020Co-Authors: Zhong Xiang Cheah, Stephen Harper, T J Ohare, Michael J. BellAbstract: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.
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Variation in zinc concentration of Sweetcorn kernels reflects source-sink dynamics influenced by kernel number.
Journal of experimental botany, 2020Co-Authors: Zhong Xiang Cheah, Tim J. O'hare, Stephen Harper, Michael J. BellAbstract:Grain yield and mineral nutrient concentration in cereal crops are usually inversely correlated, undermining biofortification efforts. 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 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 that decrease occurring to similar extents in both the embryo tissue and 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 responses in assimilate and Zn distribution 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.
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Zinc biofortification of immature maize and Sweetcorn (Zea mays L.) kernels for human health
Scientia Horticulturae, 2020Co-Authors: Zhong Xiang Cheah, Tim J. O'hare, Stephen Harper, Jitka Kochanek, Michael J. BellAbstract: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.
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Elevated zinc concentration in zeaxanthin-biofortified Sweetcorn kernels compared with a commercial hybrid
Acta Horticulturae, 2020Co-Authors: Zhong Xiang Cheah, Tim J. O'hare, Stephen Harper, Michael J. BellAbstract: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
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Speciation and accumulation of Zn in Sweetcorn kernels for genetic and agronomic biofortification programs
Planta, 2019Co-Authors: Zhong Xiang Cheah, Tim J. O'hare, Stephen Harper, Peter M. Kopittke, Gregor Meyer, Michael J. BellAbstract: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.
Amando Ordás - One of the best experts on this subject based on the ideXlab platform.
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Agronomic performance of Sweetcorn populations derived from crosses between
2015Co-Authors: Ana Butrón, A. Alvarez, Pedro Revilla, Rosa Ana Malvar, Víctor M. Rodríguez, J.i. Ruiz De Galarreta, Amando OrdásAbstract:Sweetcorn and field cor
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Adaptation of super-sweet maize to cold conditions: mutant × genotype interaction.
The Journal of Agricultural Science, 2010Co-Authors: Bernardo Ordás, Rosa Ana Malvar, Víctor M. Rodríguez, Amando Ordás, M. C. Romay, Pedro RevillaAbstract:SUMMARY Super-sweet maize (shrunken2, sh2) has a longer post-harvest life than standard Sweetcorn (sugary1, su1), but is less well-adapted to cold conditions. The objective of the present work was to determine if the replacement of su1 by sh2 alters the combining abilities of Sweetcorn inbreds for adaptation to early planting under cold conditions. Two diallel sets of su1 and sh2 near-isogenic inbred lines were evaluated in a cold chamber and by early field planting. For most of the traits related to adaptation, except silking date, there were significant mutantrgenotype interactions and the estimates of general combining ability (GCA) of each version of the same inbred were different, probably due to epistasis. Therefore, to widen the genetic base of the super-sweet germplasm for adaptation, conversion of the earliest su1 inbreds to sh2, ignoring other characteristics such as emergence or early vigour in early planting or cold tests, is proposed.
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Agronomic performance of Sweetcorn populations derived from crosses between Sweetcorn and field corn.
Spanish Journal of Agricultural Research, 2008Co-Authors: Ana Butrón, A. Alvarez, Pedro Revilla, Rosa Ana Malvar, Víctor M. Rodríguez, J.i. Ruiz De Galarreta, Amando OrdásAbstract:The adaptation of Sweetcorn (Zea mays L.) to Spanish growing conditions needs to be improved, something that could be achieved by incorporating traits from field corn populations. The aim of the present study was to analyse the performance of Sweetcorn populations carrying the genes sugary1 (su1) or shrunken2 (sh2), as well as sugary enhancer double mutants (su1 se1), produced by crosses between Sweetcorn donor populations and the Spanish field corn populations Lazcano, Oroso and Rastrojero. The three field corn populations plus the su1, su1 se1 and sh2 populations derived from them, as well as the su1, su1 se1, and sh2 donor populations used in the crosses with the field corn populations, were evaluated for their agronomic performance. Several hybrids were used as controls. Assessments were made in Zaragoza (NE Spain) and Pontevedra (NW Spain) over two years. The ability of the field corn populations to improve the Sweetcorn varieties was not greatly affected by the Sweetcorn mutant involved. The field corn populations chosen as donors for improving Sweetcorn must depend on the growing conditions in mind. Sweetcorn populations derived Oroso would appear to be the most favourable for northern Spain, while those derived from Rastrojero would appear to be the most suitable for inland Spain, although other field corn populations are still to be examined. Additional key words: maize, shrunken, sugary, sugary enhancer.
