Understanding the water use of drought-tolerant crops of the drought-prone Mediterranean regions is important for sustainable agriculture. The aim of this study was to evaluate the yield and yield responses of amaranth (Amaranthus hybridus L.) to different irrigation strategies conducted in 2019 and 2020 under Mediterranean climatic conditions using surface drip (SD) and subsurface drip (SSD) systems. Strategies investigated were: regulated deficit irrigation (RDI), conventional deficit irrigation (DI25, DI50, DI75), full irrigation (FI) and rainfed treatment. The highest grain yield was observed in FI treatments; RDI treatments produced 5% lower grain yield than the FI treatments, although the RDI treatments resulted in water savings of 23 and 21% for SD and SSD systems, respectively. DI treatments resulted in lower leaf water potential (LWP) and higher crop water-stress index (CWSI) compared to FI in both systems values. The results showed that optimum irrigation conditions to obtain the highest amaranth grain yields were associated with an LWP of −1.0 MPa and an average CWSI of about 0.25. The FI treatments under SSD systems had the highest grain production, followed by FI under SD and RDI under both the drip systems. Under SD and SSD systems, RDI saved 23 and 21% water, respectively, and produced a yield statistically comparable to that of FI. The SSD methods generated higher net income than SD. From these results it can be concluded that both RDI and DI75 could be a good alternative to FI under the conditions of water scarcity in the Mediterranean region.

Amaranth, with its high genetic variability, holds promise for global food security, income generation and climate resilience. Developing stable, high-yielding genotypes is essential for sustainable production. In this study, stability analysis was conducted on five Amaranth accessions over two seasons at three Malawian sites. Significant trait variations, including grain yield, plant height and leaf characteristics, underscored the dynamic nature of Amaranth cultivation. Notably, LL-BH-04 consistently exhibited superior grain yield, while others showed variable performance, highlighting the importance of stability analysis. Employing the Eberhart and Russell model, stable accessions in leaf and grain yield were identified. Additionally, AMMI (Additive Main effects and Multiplicative Interaction) biplot analysis revealed genetic diversity and stability patterns, aiding resilient cultivar selection. Consequently, LL-BH-04 and PE-UP-BH-01, identified as stable genotypes, were recommended for release, thereby enhancing agricultural sustainability and food security. These findings emphasize the need for site-specific breeding evaluations for sustainable productivity and underscore the importance of selecting stable cultivars to address agricultural challenges. LL-BH-04 and PE-LO-BH-01 were proposed for release to boost Amaranth production in Malawi, serving as the foundation for tailored breeding efforts aimed at improving productivity and resilience. This study contributes valuable insights into the stability and performance of Amaranth cultivars, offering guidance for sustainable crop production and variety development strategies.

The Tiwanaku civilization (around AD 500–1100) originated in the Bolivian altiplano of the south-central Andes and established agrarian colonies (AD 600–1100) in the Peruvian coastal valleys. Current dietary investigations at Tiwanaku colonial sites focus on maize, a coastal valley cultivar with ritual and political significance. Here, we examine Tiwanaku provincial foodways and ask to what degree the Tiwanaku settlers maintained their culinary and agrarian traditions as they migrated into the lower-altitude coastal valleys to farm the land. We analyze archaeobotanical remains from the Tiwanaku site of Cerro San Antonio (600 m asl) in the Locumba Valley and compare them to data from the Tiwanaku site in the altiplano and the Rio Muerto site in the Moquegua Valley during the period of state expansion. Our findings show high proportions of wild, weedy, and domesticated Amaranthaceae cultivars, suggesting that Tiwanaku colonists grew traditional high-valley (2,000–3,000 m asl) and altiplano (3,000–4,000 m asl) foods on the lowland frontier because of their established cultural dietary preferences and Amaranthaceae's ability to adapt to various agroclimatic and edaphic conditions.

We report here the first domesticated amaranth (Amaranthus spp.) seeds to be identified at a Chacoan great house, from the northern New Mexico site known as Aztec North, where they were found in a context that dates to the mid to late twelfth century AD. Amaranth has long been recognized as an important prehispanic resource in this region, evidenced by the archaeological record of both wild and domesticated forms and by the traditional knowledge and practices of Indigenous communities. Wild amaranth and similar-appearing chenopod/goosefoot (Chenopodium spp.) seeds are routinely found in Ancestral Puebloan contexts. Recent archaeological testing at the Aztec North great house, a Chaco Canyon outlier associated with a post-Chacoan political center, has revealed the presence of uncharred domesticated amaranth seeds in a thin layer of ashy trash in a room at the rear of the great house. These seeds expand our understanding of domesticated amaranth in the American Southwest and suggest centuries of continuity of traditional amaranth cultivation within Puebloan communities.

The temperature-dependent development of Apanteles hemara (Nixon), a larval endoparasitoid of the devastating amaranth pest Spoladea recurvalis (F.) was studied in the laboratory at six constant temperatures (10, 15, 20, 25, 30 and 35 °C), a photoperiod of 12L:12D and a relative humidity of 60–70%. Developmental time decreased significantly with increasing temperature within the range of 15–30 °C. The parasitoid's pupal mortality, successful parasitism rate, adult emergence rate and longevity, sex ratio and fecundity were affected by temperature. The population of A. hemara failed to develop at 10 and 35 °C. The development threshold (Tmin) and the thermal constant (K) were calculated by the linear model while the lethal temperature (Tmax) was determined by the Lactin-1 model. The estimated values of Tmin, Tmax and K by the two models were 10.3 °C, 35.0 °C and 185.18 DD respectively for the total immature development. The estimated value of the optimum temperature using the Taylor model was 30.8 °C. This is the first study to report on the effect of temperature on the developmental parameters of A. hemara giving an insight into its biology. The implications of these findings for the use of A. hemara in biological control are discussed.

Vegetable and grain amaranths represent a vital source of micronutrients and protein in Asia and Africa. However, various foliar lepidopteran pests and stem-mining weevils hinder amaranth production. Insect-resistant cultivars can enhance the productivity of this crop. Here, we report on the performances of amaranth varieties screened for their resistance to insect pests under the field conditions at The World Vegetable Center stations in Asia and sub-Saharan Africa. We conducted two preliminary screening trials with a total of 263 entries from around the world in Taiwan and a third preliminary screening trial with 49 African-indigenous entries in Tanzania. Promising entries from these preliminary trials were collectively evaluated in an advanced screening trial in Tanzania, to identify lines resistant to foliar and stem-boring pests in East Africa. Four entries exhibited moderate resistance to foliar pests: TZ51 and TZ53 (Amaranthus cruentus), TZ34 (A. dubius) and TZ39 (Amaranthus sp.). Five entries showed moderate resistance to stem weevils: TZ06 and TZ27 (A. cruentus), TZ52 (A. graecizans), TZ59 (A. palmeri) and TZ07 (Amaranthus sp.). Lepidopteran pests affecting leaves were reared to adulthood and identified as Spoladea recurvalis (Crambidae), Spodoptera exigua (Noctuidae) and Spodoptera littoralis (Noctuidae). Stem weevil larvae were also reared and identified as: Neocleonus sannio Herbst, Gasteroclisus pr. rhomboidalis Boheman, Hypolixus pr. haerens Boheman and Baradine sp. (Curculionidae). These results highlight key amaranth pests in East Africa and identify insect-resistant entries that will be useful in breeding programmes and resistance studies.

Field studies were conducted to determine the effect of season-long interference of smooth pigweed or livid amaranth on the shoot dry weight and fruit yield of cucumber. Smooth pigweed or livid amaranth densities as low as 1 to 2 weeds per m2 caused a 10% yield reduction in cucumber. The biological threshold of smooth pigweed or livid amaranth with cucumber is between 6 to 8 weeds per m2. Consequently, weed interference resulted in a reduction in cucumber fruit yield. Smooth pigweed, livid amaranth, and cucumber plant dry weight decreased as weed density increased. Evaluation of smooth pigweed, livid amaranth, and cucumber mean dry weights in interspecific competition studies indicated that cucumber reduced the dry weight of both species of amaranths.

This study used a multidisciplinary approach to evaluate the potential for hydroponic production of vegetable amaranth (Amaranthus cruentus) in Kenya. Hydroponic systems have potential for increased efficiency in water and land use, but their potential has not been critically evaluated in many developing countries. To address this gap in knowledge, this study assessed the nutritional density and economic viability of hydroponic systems built from local materials. Specifically, vegetable amaranth was grown hydroponically and evaluated for increased nutritional density of key micronutrients. Manipulation of the nutrient solution used in hydroponic systems changed the bioaccumulation of zinc, iron and carotenoids, which are three of the most common micronutrients lacking in Kenyan diets. Economic viability was assessed with a benefit-cost analysis that compared three different hydroponic systems to soil-based production and purchasing vegetables from local markets. This analysis showed that none of the hydroponic systems were profitable under current conditions, but sensitivity analyses revealed certain scenarios where they could become so. Overall, hydroponic production has the potential to create nutrient-dense crops with high levels of zinc, iron, or carotenoids. However, hydroponic systems may be better suited to crops of higher value than amaranth, areas where soil-based production is not an option, or regions where vegetable markets are not available.

Chemical fertilizers for boosting crop production are becoming more expensive and scarce. Green amaranth (Amaranthus caudatus L.) is a fast growing and highly nutritious crop, but its common use in the diet of Nigerians is constrained by its high demand for nitrogen fertilizer. Thus, there is a need to find local fertilizer materials that are readily available to peasant farmers. A preliminary field study was conducted to evaluate urine and neem (Azadirachta indica L. juss) as alternative sources for mineral fertilizers in fortifying organic fertilizer (OF) made from cow dung and market waste compost, and OF fortified with urea and bone meal [organo-mineral fertilizer (OMF)], for yield and growth of green amaranth. Fifteen treatments, based on the percentages of N supplied, were NPK15-15-15, OMF, OF, urine, neem and ten treatments of 50, 60, 70, 80 or 90% OF supplemented with a total of 50, 40, 30, 20 and 10% urine or neem, respectively, to provide a total application rate of 100 kg N ha−1, with no fertilizer treatment as a control. Planting was done in two successions (main with fertilizer treatments and residual without further application). The fertilizer sources and levels had significant effects on plant height, number of leaves, stem girth, fresh weight and dry weight. The residual effects were also significant for plant height, number of leaves, total fresh and dry weights. Forty percent N urine amendment of the OF produced the highest total fresh amaranth biomass (269.3 g plot−1 main effect and 110.8 g plot−1 residual effect), which was significantly better than the values of (140 and 35.3 g plot−1, respectively) obtained with respect to OMF during main planting and NPK during residual planting. Results of our study reveal that 40% N urine fortification of OF was a viable substitute for synthetic fertilizers in production of amaranth, and that urine and neem cake can be alternatives to mineral fertilizer for crop production.

Double-cropping provides a method of diversifying the rotation, maximizing production, and increasing the profit potential of a cropping system. We assessed agronomic and economic performance of five alternative crops in comparison to the no-till wheat-soybean double-cropping system prevalent in the southern Corn Belt. Canola has shown potential as a profitable winter crop, but its effects on the subsequent crop in a no-till double-crop system required further study. Amaranth, buckwheat, sunflower, and pearl millet were planted after the harvest of canola or wheat, or after fallow. Alternative double-crop grain yield, production costs, and net returns were compared with those of double-crop soybean.

Wheat yielded more than canola. Sunflower grain yields did not differ significantly after winter-crop treatments at any site. Yields of amaranth, buckwheat, soybean, and pearl millet differed after winter crops at some sites. At three study yield levels, net returns were positive and greatest for double-crop wheat-amaranth, canola-amaranth, wheat-sunflower, and canola-sunflower systems. All double-crop systems except canolapearl millet had positive net returns at median study yield levels. Low or negative net returns resulted from the combination of low yield and low price for some double crops. Canola was shown to be an economically feasible alternative to wheat in a doublecropping system for central and southern Missouri. Buckwheat and sunflower were shown to be agronomically and economically competitive alternatives to soybean following either canola or winter wheat, with buckwheat most valuable in late-season planting conditions.