The growth chamber trial was set up in a completely randomized design with five repetitions of each treatment, and pots were rearranged during the experiment to minimize border effects. All field trials were set up in randomized complete block designs with 3 blocks. Each block contained a plot with each studied variety, and each plot contained five replicate plants for each leaf harvest intensity treatment including controls.
In both cases, five plants were assigned to each treatment. A third harvest, planned for the 18 leaf stage to mirror the growth chamber trials was canceled due to the initiation of flowering.
For both harvest frequencies, five plants were sampled for each harvest intensity and harvest frequency per block. Plants had begun to flower at the 16 leaf stage, so this trial allowed us to see the results of post-vegetative defoliation. In the field experiments, five uniform plants per plot were randomly assigned to each defoliation intensity treatment by attaching tags to the base of their stems on the day of the first harvest.
Leaves were systematically removed in equal proportion from the top to the bottom of the plant, to ensure a relatively equal balance of source and sink tissue removal.
Defoliation was done with a scalpel from the base of the petiole. To align with the production systems of the Mexican farmers who initiated these experiments, we included an amaranth variety commonly used in the Oaxaca region of Mexico. Amaranthus cruentus var. Benito seeds were chosen after consulting Dr. To test our hypothesis about widespread tolerance to defoliation across various genotypes under field conditions, we included six varieties adapted to the Danish climate, which represented the three primary grain amaranth species Table 3.
The variety used in the Mexican trial was selected based on suitability for the land chosen for the trial. Plant dry weight was taken, and the dry weight of previously harvested leaves was added to the dry weight of each mature plant to account for total harvested aboveground biomass. Total seed yield and KW were also measured. Harvest Index was calculated by dividing the seed yield by the total dry weight. Seeds from the growth chamber trial and Danish field trial were ground into a fine powder using a Foss cyclotec When ready for nitrogen analysis, each sample was ground using a mortar and pestle under liquid nitrogen.
With this method, approximately 5 g of each sample were placed in tin capsules and an exact measurement using three decimal places was taken. Organic and inorganic substances were converted into elemental gasses, which were reduced and separated into a chromatographic column and detected by a thermal conductivity detector Thermo Fisher Scientific Inc.
For the growth chamber trial, 5 g of seed from each plant were analyzed, as well as 5 g of leaves from each plant with each consecutive harvest. The percentage of nitrogen in the leaves measured in the laboratory was multiplied by the Jones Factor 6. This conversion factor is imperfect, but no conversion factor has been specified for amaranth by the Codex Alimentarius international food standards, and we were more interested in protein content differences between treatments rather than a precise measure of total protein.
Because treatment had no impact on seed protein in the growth chamber and in Danish field trial, this analysis was not repeated in the other trials in order to reduce costs.
Since defoliated plants were mixed throughout the canopy, and the majority of plants in each plot were not subject to a defoliation treatment, we took multiple measurements throughout each plot to get an estimate of average canopy cover throughout. PAR was measured both above the canopy, then below the canopy at soil level in four different locations in each plot, and again above the canopy. Light infiltration was then plotted against seed yield ratios comparing control plant seed yield to average seed yield for each defoliation treatment in each plot to determine whether canopy light interception could predict the seed yield ratio.
All analyses were done in R version For the growth chamber trial, analysis of variance ANOVA was used to test the effects of harvest treatments on each variable. Tukey tests were then used for mean separation. Plants that did not produce flowers and seed were removed from seed yield, kernel weight, and seed protein models. For repeated measures leaf biomass recovery , mixed models were built using the lme4 package in R.
The amount of biomass harvested between the first, second, and third harvest could then be compared at each harvest level individually. For the field trials, the function lmer from the package lme4 was used to develop linear mixed-effects models Bates et al. This allowed us to nest block effects within year effects, and treat both block and year as random effects. The random effects were calculated using ordinary maximum likelihood. Interactive and additive models for the fixed effects were tested using chi-square tests and plots of model residuals.
Additive models were chosen where no significant interactions were observed. Tukey tests were then used for mean separation on the chosen model. In cases where the interactive model best described the data, binary model matrices were built to define linear hypotheses and compare unique combinations of treatments and varieties using the standard Tukey honest significance difference test.
As such, we ran an additional analysis of variance to test the impact of block on seed yield. There appeared to be a slight, non-significant trend for seed yield to increase with harvest intensity following a single defoliation Figure 1. Many of the thrice defoliated plants did not flower, especially at higher harvest intensities.
While fewer plants flowered, those that did produced more seed overall. Figure 1. Bars correspond to standard error. Table 4. The distribution of residuals for the leaf biomass model was non-normal, even with transformation through Box Cox methods. Figure 2. Harvested leaf biomass at four leaf harvest intensity levels during three consecutive defoliation events in the growth chamber trial. Bars represent standard error. Figure 3. While seed yield was much higher overall in compared to , seed yield reductions relative to controls followed the same pattern each year Table 5.
Table 5. Figure 4. Because the Maria variety was only studied one of the 2 years, it was analyzed separately from the Benito data. Table 6. Total plant biomass at maturity was significantly impacted by multiple defoliation events for both the A. Despite differences in control seed yield, patterns in seed yield tolerance at different levels of defoliation were similar to Danish results.
Table 7. Tukey tests were done on each unique combination of variety and harvest intensity, and showed that the leaf harvest intensity level only affected the seed protein content of varieties Maria and Katia, without a clear response pattern as harvest intensity increased Table 8.
As such, protein results did not show conclusive trends, and did not suggest significant variation between treatments. Therefore, further protein analysis was not pursued. Its name in the Aztec language Nahuatl was huauhtli. The Mixtecs of Oaxaca also assigned great importance to this plant. The Postclassic turquoise mosaic covering the skull encountered within Tomb 7 at Monte Alban was actually kept together by a sticky amaranth paste.
Cultivation of amaranth decreased and almost disappeared in Colonial times, under the Spanish rule. The Spanish banished the crop because of its religious importance and use in ceremonies that the newcomers were trying to extirpate. Edited and updated by K. Kris Hirst. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content.
Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile. The archeological record indicates that A. Examples of the pale form of A cruentas have been found in the caves at Tehuacan Puebla in Mexico , an early agricultural site, dating from around BC.
It is believed the seeds migrated to Tehuacan from their original domestication point elsewhere. Historic records document amaranth across regions of Central America, and into the southwestern part of North America. Amaranth has been found in Ozark rock shelters dated from AD, and colonial explorers from the midth century documented obtaining amaranth seeds from the indigenous tribes along the Colorado River in what is now Arizona and Utah.
The most robust record of amaranth comes from the Aztec empire, which dominated central Mexico in the 15th and 16th centuries AD.
Amaranth was one of the three major crops collected , along with maize and beans, as tribute from the 17 provinces that made up the Empire. The historical records show that much of the amaranth collected was used for ceremonial purposes, unlike maize and beans which were largely collected for consumption.
Sweet snacks made from popped amaranth mixed with a binding agent such as honey are still a popular way of consuming amaranth in Central and South America today. Amaranth is also very present to the archeological and historic record in Southeast Asia and China.
Amaranth seeds found in Uttar Pradesh date back to BC. Nowadays the various species from the different tropical regions are pretty much scrambled up genetically, so that the origins of any given amaranth plant remain at least for the. Fox, F. Norwood Young. Delta Books, Pty Ltd. Many of the more than fifty Amaranthus species in both tropical and temperate regions are eaten, but only a dozen or so can be considered domesticated.
They secure the food supply for millions. The leaves and stems make excellent boiled vegetables with soft texture, mild flavor, and no trace of bitterness. Jim Rakocy. Amaranth leaves and stems make boiled vegetables with soft texture, mild flavor, and no trace of bitterness.
In taste tests at the U. Department of Agriculture in Beltsville, Maryland, most of the 60 participants said that cooked amaranth leaves tasted at least as good as spinach. Some likened the taste to that of artichoke. But such is not the case. Amaranths produce seeds aplenty and their seedlings emerge so rapidly and sprout with such vigor that the first crop of leaves is sometimes harvested within three weeks of planting.
Furthermore, new generations of leaves keep materializing, so that many harvests can be made before replanting becomes necessary. Generally the wild species are considered to have hybridized frequently with the cultivated and thus produced a series of intermediate types. Actually, they have high food value. The leaves have an exceptional protein quality, 25 percent for Amaranthus cruentus reportedly containing more lysine about 0.
In addition, vitamins A and C occur in good quantities. Minerals such as calcium and iron are also present in abundance. Given their lack of recognition one might imagine these lowly plants to possess such strict climatic and soil requirements that they grow well only in limited locations. Once more, however, the truth is quite the reverse. Amaranths demonstrate exceptional vitality in many types of sites.
Most are pioneer species, whose niche in nature is the quick colonization of disturbed land. Although in most of the lowland tropics the upper crust may hold vegetable amaranths in low esteem, in Caribbean nations the whole society honors these plants. Callaloo is so central to the diet that it has become almost synonymous with the Caribbean image. The word has entered everyday talk as a word denoting the unique blending of food, language, music, and peoples constituting Creole culture.
The name callaloo is appended to restaurants, magazines, shows, songs, bands, books, and more. It is an appellation bestowed with pride. In China and Southeast Asia, a region renowned for quality vegetables, one amaranth—Chinese spinach, Amaranthus tricolor —ranks among the very best.
Those in Taiwan grow a type called tiger leaf, which has green leaves with a red stripe down the center. The family was so named by Antoine Laurent de Jussieu , a remarkable botanist who named plant families.
The power of his insight can be judged from the fact that 76 of the names, including Amaranthaceae, remain in use to this day. Variously spelled callaloo, calaloo, callalou, callalou, callalu, and calalu. Herklots, G. Vegetables in South-East Asia. Hafner Press. New York. Taken all round, they represent a sort of do-it-yourself kit to good nutrition and lend themselves ideally to subsistence conditions.
With them, little horticultural experience is needed before the benefits of better nutrition can be enjoyed. Although insect pests and diseases can be problematic, few if any tropical vegetables are easier to grow. In favorable locations amaranths produce food almost without attention. Seen in overall perspective, these fighters offer frontline armaments in the battle to feed properly a malnourished world.
They yield protein and other nutrients efficiently. They afford abundant provitamin A beta-carotene , a nutrient vital to the millions of malnourished children now at risk of blindness. And they do it quickly. In summary, amaranths are an important market vegetable for many farmers, but their main benefits are humanitarian ones.
Without these humble plants, the hidden hunger of malnutrition would be much worse. With them in greater use, it can be greatly lessened. Although vegetable amaranths have yet to catch the attention of most researchers and scientific establishments, few crops can match them for effectiveness in nutritional interventions.
In places such as Africa they offer an easy entree intervention because they are even now consumed by, admired by, and sought by the rural peoples for whom food insecurity is a daily peril. Humid Areas Excellent. Amaranthus species are of course already used widely as potherbs in the humid lowland tropics.
Over the years, growers have selected types with leaves and stems of high palatability. The mild taste, high yields, high nutritive value, and ability to withstand hot climates make them popular. Dry Areas Modest. Given their C4 photosynthesis, amaranths thrive, or at least survive, under droughty conditions. However, for good production under dry conditions supplemental water must be applied. The plants tend to grow very rapidly and they have high leaf areas and thus high evaporation losses , so to attain top production and maximum palatability they require.
Upland Areas Good. With a fast-growing leaf crop like this, altitude is little barrier. Amaranth was a mainstay of ancient South American civilizations, produced at about the highest elevations known to agriculture. Nothing restricts these plants to Africa. Prospects elsewhere are excellent. Indeed, the leafy amaranths have reached their greatest development in Asia. Furthermore, many species from this genus are cultivated in Mexico as well as in Central and South America.
And in the Caribbean, of course, they are a mainstay of the traditional cuisine. Leaves Leaves, young stems, and young inflorescences are eaten as potherbs. Although much of the pigment leaches out on boiling, the leaves retain a pleasant green color.
They soften up readily, requiring only a few minutes cooking, which helps avoid excessive nutrient loss. Unlike some African potherbs, they need no added soda or potash to make them palatable. The leaf is also tossed into soups and stews.
The boiled leaves may be rubbed through a fine sieve and served as a puree. Salad Plant Very young leaves may be used in a mixed salad. Sometimes the whole plant is pulled up after it has developed eight or twelve leaves, and used directly in salads. The flowers, however, are inedible. Seeds Several species, including Amaranthus cruentus , A. Although small, these seeds occur in prodigious quantities.
In carbohydrate content they equal cereals such as wheat, but have more protein over 17 percent in some strains and more oil. When heated, amaranth grains burst and take on a toasted flavor not unlike that of popcorn, which is very appealing.
However, in many areas, they are more often parched and milled into flour. Bread made this way has a delicate, nutty flavor and is used notably by gluten-sensitive individuals. Pancake-like chapatis made from. Stems While most leaf amaranths are about 60 cm high, some varieties reach 2 m. It is reported that Singaporeans peel the stem of one of these tall forms and eat it separately.
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