Millet Species Research Articles

Millets genetic engineering: the progress made and prospects for the future

Millets comprise a highly variable small-seeded group of Poaceae members that can grow in extreme environmental conditions of drought, high temperature and low soil fertility hence, recognized as climate-resilient. Among millets, the phylogenetic closeness of Setaria with other agronomically important grasses like maize, sugarcane, and sorghum helped in its adoption as a translational model plant. Established efficient gene transfer methodology is a prerequisite for embracing plant species as models. However, genetic engineering of some of the economically important millets has been started in the 1990s, but inadequate progress made this group lag behind other members of Poaceae as rice, maize and wheat. Genetic transformation in millets has generally been achieved by a physical method of microprojectile bombardment, recently Agrobacterium-mediated gene transfer technique has also established in some of the millets but with very few reports. The central hindrance in millet transformation is its recalcitrant nature to regeneration through tissue culture techniques. Optimization of highly efficient regeneration procedure for each millet species is thus, necessary to establish advanced transformation system for them. The possibility of alternative transformation approaches is also discussed. The establishment of robust gene transfer methods whether it’s conventional in-vitro tissue culture dependent or in-planta are important for functional validation studies and would enable development of crop improvement strategies. This review presents the progress made on millet genetic transformation, discussing the major challenges that need to be overcome and future opportunities of transgenic techniques in various millets.

Management of Economically Important Insect Pests of Millet

AbstractGrain of various species of millet is a staple food of rural communities in sub-Saharan Africa, the Indian subcontinent, and China. In addition, millet is used as poultry and cattle feed in the United States, and the foliage is fodder for cattle in India. The crop is damaged by at least 150 insect pests during its growth and development. Although the current status of all of these pests is not known, shoot flies, stem borers, leaf-sucking, and the panicle-attacking insects are considered economically important. Control measures include the application of synthetic pesticides (as both seed treatment and foliar applications) and cultural methods (timing of planting and field sanitation). Host plant resistance (screening of genotypes and breeding of pest-tolerant/resistant cultivars), and biological control (conservation of natural enemies and periodical releases of the larval parasitoid Habrobracon hebetor) have received much attention in recent years. Integrating available pest control options has been recommended, along with further adoption of new crop cultivation technologies by small and resource-poor farmers.

Drought-tolerance mechanisms in foxtail millet (Setaria italica) and proso millet (Panicum miliaceum) under different nitrogen supply and sowing dates

Drought stress is one of the main limitations to crop growth and yield. Efficient nitrogen (N) nutrition may moderate the negative effects of drought stress on plants through retention of metabolic activities. The present study was conducted to investigate the biochemical responses of two millet species, foxtail millet (Setaria italica (L.) P.Beauv.) and proso millet (Panicum miliaceum L.), under two irrigation regimes (based on 55% and 85% soil-water depletion) and two N fertiliser levels (0 and 112.5 kg N ha–1) at four sowing dates (22 June and 6 July 2015, 14 and 30 June 2016). Drought stress increased hydrogen peroxide (H2O2), malondialdehyde (MDA) and other aldehyde contents of the plants, ultimately leading to 52% and 55% reductions in grain yield in foxtail millet and proso millet, respectively. Antioxidant activities showed significant increases under drought stress. Nitrogen application decreased H2O2, MDA and other aldehyde contents and activities of antioxidant enzymes, whereas it increased chlorophyll, carotenoid, phenolic compound and proline contents as well as grain yield. Higher grain yields were obtained with early planting dates under sufficient water supply, whereas superior yields were obtained with delayed planting dates under water stress owing to lower temperatures and evaporation rates. The results suggest that N application could mitigate the adverse effects of drought stress on millet plants by promoting osmoregulation, alleviating lipid peroxidation, and improving plant physiological traits. Foxtail millet had higher antioxidant potential than proso millet, resulting in greater capacity to inhibit production of free oxygen radicals and making it the more drought-tolerant species.

Waxy allele diversification in foxtail millet (Setaria italica) landraces of Taiwan.

Foxtail millet (Setaria italica (L.) P. Beauv.), the second most cultivated millet species, is well adapted to diverse environments and remains an important cereal food and forage crop in arid and semiarid regions worldwide. A symbolic crop for indigenous Austronesian peoples, foxtail millet has been cultivated in Taiwan for more than 5,000 years, and landraces reflect diversifying selection for various food applications. A total of 124 accessions collected within Taiwan were assessed for Wx genotypes. Four identified Wx alleles, I, III, IV, and IX were caused by insertion of various transposable elements (TEs) and resulted in endosperm with non-waxy, low amylose content (AC), and waxy, respectively. A total of 16.9%, 4.0%, 49.2%, and 29.8% of accessions were classified as type I, III, IV, and IX, respectively; approximately half of the accessions belonged to the waxy type, indicating that glutinous grains were favored for making traditional food and wine. The TE insertion affected splicing efficiency rather than accuracy, leading to significantly reduced expression of wx in types III, IV, and IX, although their transcripts were the same as wild-type, type I. Consequently, the granule-bound starch synthase I (GBSSI) contents of the three mutated genotypes were relatively low, leading to waxy or low AC endosperm, and the Wx genotypes could explain 78% of variance in AC. The geographic distribution of Wx genotypes are associated with culinary preferences and migration routes of Taiwanese indigenous peoples—in particular, the genotype of landraces collected from Orchid Island was distinct from those from Taiwan Island. This information on the major gene regulating starch biosynthesis in foxtail millet endosperm can be applied to breeding programs for grain quality, and contributes to knowledge of Austronesian cultures.

Microsatellite markers of finger millet (Eleusine coracana (L.) Gaertn) and foxtail millet (Setaria italica (L.) Beauv) provide resources for cross-genome transferability and genetic diversity analyses in other millets

The cross-genome transferability of 101 simple sequence repeats (SSR) markers of finger millet and 26 SSR markers of foxtail millet were analyzed in 8 other millets. In total, 33 finger millet and 2 foxtail millet SSR markers showed 100% cross-genome transferability in other millets. The cross-genome transferability of 101 finger millet and 26 foxtail millet SSR markers ranged from 47.52% to 61.38% and from 30.76% to 69.23% respectively. Expressed sequence tags SSR (EST-SSR) markers of finger millet showed higher level of cross-genome transferability than genomic SSR (gSSR) markers. The observed polymorphic information content (PIC) values were the same for finger millet and foxtail millet SSR markers which ranged from 0.14 to 1.00. Further, these data were also used for genetic diversity analysis among 8 millets using the software version 2.1 of NTSYSpc tool and PAST version 2. All millet species were grouped into one major cluster based on finger millet SSR markers, through UPGMA analysis. But two major clusters were observed by the analysis using foxtail millet SSR markers. Similarity value ranged from 0.238 to 0.714. Higher bootstrap values were observed in all cluster nodes. Successful analysis of genetic diversity was also confirmed by PCO and PCA analyses. This study would pave the way to understand the genetic structure of many nutritionally important millets lacking genomic resources. The SSR markers can also be used for further studies on analysis of genetic variation, population structure and germplasm characterization of millets.

Carbon and nitrogen isotope variability in the seeds of two African millet species: Pennisetum glaucum and Eleusine coracana.

A range of important small seeded C4 crops were domesticated in Africa, but little is known about their carbon and nitrogen isotope ratios (δ13 C and δ15 N values). Understanding natural isotopic variability within and among millets has the potential to help us to understand the conditions under which ancient cereals were grown and has significant implications for the interpretation of ancient diets based on stable isotope signatures. We conducted carbon and nitrogen isotope analyses of modern and historical pearl millet (Pennisetum glaucum, n=108) and finger millet (Eleusine coracana, n=17) seed samples sourced from the United States Department of Agriculture as well as the Harlan Collection curated at the Crop Evolution Laboratory Herbarium at the University of Illinois. The millet species have significantly different mean carbon and nitrogen isotope ratios over broad temporal and spatial scales. We also found substantial isotopic variation within species (range of 1.9‰ and 8.5‰ in δ13 C and δ15 N values, respectively). Both water availability and growing season temperature significantly affected the P. glaucum δ13 C and δ15 N values; cumulative annual precipitation was positively correlated with both seed δ13 C and δ15 N values, while temperature was positively correlated with δ15 N values but negatively correlated with seed δ13 C values. The importance of both temperature and precipitation as predictors of δ13 C and δ15 N values in millets suggests that C4 plants may be more sensitive to environmental parameters than previously appreciated. Given the high degree of carbon and nitrogen isotope variability among accessions of these species, it is imperative that site-relevant plant isotope ratios are used for making isotope-based paleo-dietary predictions.

Antinutritional factors in pearl millet grains: Phytate and goitrogens content variability and molecular characterization of genes involved in their pathways.

Pearl millet [Pennisetum glaucum (L.) R. Br.] is an important “orphan” cereal and the most widely grown of all the millet species worldwide. It is also the sixth most important cereal in the world after wheat, rice, maize, barley, and sorghum, being largely grown and used in West Africa as well as in India and Pakistan. The present study was carried out in the frame of a program designed to increase benefits and reduce potential health problems deriving from the consumption of pearl millet. The specific goal was to provide a database of information on the variability existing in pearl millet germplasm as to the amounts of phytate, the most relevant antinutrient compound, and the goitrogenic compounds C-glycosylflavones (C-GFs) accumulated in the grain.Results we obtained clearly show that, as indicated by the range in values, a substantial variability subsists across the investigated pearl millet inbred lines as regards the grain level of phytic acid phosphate, while the amount of C-GFs shows a very high variation. Suitable potential parents to be used in breeding programs can be therefore chosen from the surveyed material in order to create new germplasm with increased nutritional quality and food safety. Moreover, we report novel molecular data showing which genes are more relevant for phytic acid biosynthesis in the seeds as well as a preliminary analysis of a pearl millet orthologous gene for C-GFs biosynthesis. These results open the way to dissect the genetic determinants controlling key seed nutritional phenotypes and to the characterization of their impact on grain nutritional value in pearl millet.

Critical role of climate change in plant selection and millet domestication in North China

While North China is one of the earliest independent centers for cereal domestication in the world, the earliest stages of the long process of agricultural origins remain unclear. While only millets were eventually domesticated in early sedentary societies there, recent archaeobotanical evidence reported here indicates that grasses from the Paniceae (including millets) and Triticeae tribes were exploited together by foraging groups from the Last Glacial Maximum to the mid-Holocene. Here we explore how and why millets were selected for domestication while Triticeae were abandoned. We document the different exploitation and cultivation trajectories of the two tribes employing ancient starch data derived from nine archaeological sites dating from 25,000 to 5500 cal BP (LGM through mid-Holocene) in North China. With this diachronic overview, we can place the trajectories into the context of paleoclimatic reconstructions for this period. Entering the Holocene, climatic changes increased the yield stability, abundance, and availability of the wild progenitors of millets, with growing conditions increasingly favoring millets while becoming more unfavorable for grasses of the Triticeae tribe. We thus hypothesize that climate change played a critical role in the selection of millet species for domestication in North China, with early domestication evidenced by 8700 cal BP.

Reversal Effects of Bound Polyphenol from Foxtail Millet Bran on Multidrug Resistance in Human HCT-8/Fu Colorectal Cancer Cell.

Foxtail millet is the second-most widely planted species of millet and the most important cereal food in China. Our previous study showed that bound polyphenol of inner shell (BPIS) from foxtail millet bran displayed effective antitumor activities in vitro and in vivo. The present research further implied that BPIS has the ability to reverse the multidrug resistance of colorectal cancer in human HCT-8/Fu cells, the IC50 values of 5-fluorouracil (5-Fu), oxaliplatin (L-OHP), and vincristine (VCR) were decreased form 6593 ± 53.8, 799 ± 48.9, and 247 ± 10.3 μM to 5350 ± 22.3 (3261 ± 56.9), 416 ± 16.6 (252 ± 15.6), and 144 ± 8.30 (83.8 ± 5.60) μM when HCT-8/Fu cells were pretreated with 0.5 (1.0) mg/mL BPIS for 12 h. The 12 phenolic acid compounds of BPIS were identified by ultraperformance liquid chromatography-triple-time of flight/mass spectrometry (UPLC-Triple-TOF/MS) method. Especially, the fraction of molecular weight (MW) < 200 of BPIS reversed the multidrug resistance in HCT-8/Fu cells, and ferulic acid and p-coumaric acid were the main active components, the IC50 values were 1.23 ± 0.195 and 2.68 ± 0.163 mg/mL, respectively. The present data implied that BPIS significantly enhanced the sensitivity of chemotherapeutic drugs through inhibiting cell proliferation, promoting cell apoptosis, and increasing the accumulation of rhodamine-123 (Rh-123) in HCT-8/Fu cells. Real-time polymerase chain reaction (RT-PCR) and Western blot data indicated that BPIS also decreased the expression levels of multidrug resistance protein 1 (MRP1), P-glycoprotein (P-gp), and breast cancer resistance protein (BCRP). Collectively, these results show that BPIS has potential ability to be used as a new drug-resistance reversal agent in colorectal cancer.

Indices of forage nutritional yield and water use efficiency amongst spring-sown annual forage crops in north-west China

Abstract Livestock production in China is increasing to meet demands for animal products, but is limited by feed resources. To explore additional forage options in north-west China, the biomass production and nutritive value of nine spring-sown annual crops (maize (Zea mays), sudan grass (Sorghum sudanense), small millet (Setaria italica), millet (Panicum milliaceum), soybean (Glycine max), common vetch (Vicia sativa), pea (Pisum sativum), oat (Avena sativa) and spring wheat (Triticum aestivum)) were compared under rainfed conditions over two years. Water use efficiencies for biomass (WUEDM) and nutritional yield indices, CP yield (WUECP) and relative feed value yield (WUERFV), were calculated. Maize produced the highest biomass yields of >10 t DM ha−1 and had the highest WUEDM. Biomass production was next highest in the other warm-season grasses such as sudan grass and millet species (6–9 t DM ha−1) and soybean (3–7 t DM ha−1), while spring wheat produced the most early biomass in spring (P

Potential of Three Trap Crops in Managing Nezara viridula (Hemiptera: Pentatomidae) on Tomatoes in Florida.

The southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae), is a serious insect pest of tomatoes in Florida. In this study, we examined the use of three species of trap crops to manage N. viridula in North Florida tomato crops in 2014 and 2015. We used striped sunflower (Helianthus annuus) (Asterales: Asteraceae) and wild game feed sorghum (Sorghum bicolor) (Poales: Poaceae) in both years, but different species of millet each year: browntop millet (Panicum ramosum) (Poales: Poaceae) in 2014 and pearl millet (Pennisetum glaucum) (Poales: Poaceae) in 2015. The number of stink bug adults collected from wild game feed sorghum exceeded the number from sunflower, and none were collected from either species of millet. Sorghum attracted a significantly higher number of adults than did striped sunflower; however, both sunflower and sorghum attracted the adults of N. viridula. Adults of the pest feed on the sorghum panicle and sunflower head (inflorescence). Although fewer stink bugs were found feeding on sunflower, the sunflower was found to be a good source of other natural enemies and pollinators and also attracted significantly greater numbers of the brown stink bug Euschistus servus (Say) (Hemiptera: Pentatomidae) (another pest of tomatoes). While this study demonstrated the effectiveness of sorghum, we recommend that sorghum be planted with another trap crop, preferably sunflower, for better preventive control of the southern green stink bug.

English

Foxtail millet (Setaria italica) is the second-most widely planted species of millet. It is nutritionally superior to conventional food grains and exhibits hypoglycaemic effect due to presence of higher proportion of unavailable complex carbohydrate and resistant starch. Vermicelli is a popular instant food product which is tasty and easy to make, liked by people of all walks of life, irrespective of age and changing lifestyles. Hence, an attempt was made to develop foxtail millet based value added vermicelli. Standardization trials indicated that acceptable foxtail millet vermicelli could be developed by substituting 50 per cent processed foxtail millet flour in the standard vermicelli recipe. In order to improve functional properties of vermicelli further different trials were carried out by replacing wheat semolina with black gram dhal flour. Black gram dal flour was incorporated at 5, 10, 15 and 20 per cent levels by substituting wheat semolina while level of foxtail millet flour was kept constant at 50 percent. Among all the trials, vermicelli with 20 percent black gram dhal flour was found to be highly acceptable. To improve nutritional quality of developed vermicelli an attempt was made to incorporate fenugreek seed powder at level of 1, 2 and 3 percent, among which vermicelli from 1 percent fenugreek seed powder was found to be acceptable as compared to other samples. Cooking, textural and sensory properties of formulated vermicelli were observed and compared with the control. Thus, the study presented an upshot of potentials of foxtail millet as a natural designer health food for patients suffering with life style diseases.

Cereals, calories and change: exploring approaches to quantification in Indus archaeobotany

Several major cereal groups have been identified as staples used by the pre-urban, urban and post-urban phase populations of the Indus Civilisation (3200–1500 BCE): wheat, barley, a range of small hulled millets and also rice, though their proportional exploitation is variable across space and over time. Traditional quantification methods examine the frequency, intensity and proportionality of the use of these crops and help ascertain the ‘relative importance’ of these cereals for Indus populations. However, this notion of ‘importance’ is abstracted from the daily lives of the people using these crops and may be biased by the differential production (as well as archaeological survival) of individual cereals. This paper outlines an alternative approach to quantifying Indus cereals by investigating proportions of calories. Cereals are predominantly composed of carbohydrates and therefore provided much of the daily caloric intake among many late Holocene farming populations. The four major cereal groups cultivated by Indus farmers, however, vary greatly in terms of calories per grain, and this has an impact on their proportional input to past diets. This paper demonstrates that, when converted to proportions of calories, the perceived ‘importance’ of cereals from five Indus sites changes dramatically, reducing the role of the previously dominant small hulled millet species and elevating the role of Triticoid grains. Although other factors will also have affected how a farmer perceived the role and importance of a crop, including its ecological tolerances, investments required to grow it, and the crop’s role in the economy, this papers suggests that some consideration of what cereals meant in terms of daily lives is needed alongside the more abstracted quantification methods that have traditionally been applied.

Genetic diversity of disease resistance genes in foxtail millet (Setaria italica L.)

Foxtail millet (Setaria italica L.) is a potential biofuel plant species, which is also one of the most commonly cultivated millet species for food and fodder. In this study we aimed to conduct a genome-wide identification of Coiled-coil, Nucleotide-binding site, Leucine-rice repeat (CNL) disease resistance genes (R-genes) in foxtail millet and study their evolutionary relationships. We identified 242 CNL genes with domains for NBS-LRR receptor function, with the addition of a few genes that contained transmembrane or zinc finger domains. Of the identified CNL genes, more than half formed gene clusters within the foxtail millet genome, with the majority showing evidence of tandem duplications. Syntenic analysis displayed chromosomal similarities among foxtail millet, rice, and barley, identifying strong syntenic relationships between foxtail millet and rice. Approximately 30% of the foxtail millet CNL gene clusters were found on chromosome Si08, exhibiting strong synteny with chromosome Os11 of rice. Selection pressure analysis showed a prevalence of purifying selection among all phylogenetic clades. We also identified the foxtail millet homologs of several well-studied R-genes in other species. The results from this study will have implications in research on CNL gene signaling pathways and development of durable resistance in foxtail millet and other crop species in general.

Broomcorn and foxtail millet were cultivated in Taiwan about 5000\xa0years ago

BackgroundArchaeobotanical remains of millet were found at the Nan-kuan-li East site in Tainan Science Park, southern Taiwan. This site, dated around 5000–4300 BP, is characterized by remains of the Tapenkeng culture, the earliest Neolithic culture found so far in Taiwan. A large number of millet-like carbonized and charred seeds with varied sizes and shapes were unearthed from the site by the flotation method. Since no millet grain was ever found archaeologically in Taiwan previously, this discovery is of great importance and significance. This paper is in an attempt to further analyze these plant remains for a clearer understanding of the agricultural practice of the ancient inhabitants of the Nan-kuan-li East site.ResultWe used light and scanning electron microscopy to examine the morphological features of some modern domesticated and unearthed seeds to compare and identify the archaeobotanical remains by three criteria: caryopsis shape, embryo notch, and morphology of lemma and palea. We also developed a new methodology for distinguishing the excavated foxtail and broomcorn millet seeds.ConclusionTwo domesticated millet, including broomcorn millet (Panicum miliaceum) and foxtail millet (Setaria italica), as well as one wild millet species, yellow foxtail (Setaria glauca), were identified in the unearthed seeds. Together with the millet remains, rice was also cultivated in the area. Archaeological evidence shows that millet and rice farming may have been important food sources for people living about 5000 years ago in southern Taiwan.

Comparative genetic analysis of wild finger millet accessions using finger millet and maize microsatellite markers

The genomic information available for finger millet is very scarce though the plant is a rich source of highly digestible proteins and dietary fibre with good amounts of soluble and insoluble fractions. In present study, 64 maize and finger millet genomic SSRs were used for cross transferability, identification of polymorphic markers and genetic diversity of finger millet, both cultivated and wild species. Out of 64 SSRs, only 43 (67%) were amplified across the finger millet genotypes. The PIC values of all the polymorphic loci across the 23 finger millet genotypes varied from 0.04 to 0.47 (average value 0.17). Based on the parameters of PIC values ≥ 0.26, gene diversity ≥0.43, inbreeding coefficient ≥ 0.60, the SSR loci UGEP33, UMC1858, UMC1805, and UMC2163 were found highly polymorphic. Comparison of SSR polymorphism in finger millet genotypes revealed that microsatellites of maize were more polymorphic and were able to identify more diversity in finger millet genotypes than the finger millet SSRs. Good correlations were found between genetic diversity analysis in differentiation of finger millet genotypes using finger millet and maize microsatellite markers. Dendrogram generated through UPGMA analysis grouped all the 23 genotypes clustered them into two major groups A and B with maximum similarity found between genotype pairs T552, T622 and T507, T74. The genotype pairs T671 and T760; T187 and T 631, T824 showed lowest similarity in finger millet which could be selected for hybrid plant production. The present study enriched the finger millet genomics by identifying suitable polymorphic markers of maize and finger millet, which can be used for diversity analysis, cultivar identification and QTL mapping studies.

The final sterilization of Earth

The image on this issue’s cover is a close-up of coral polyps. You can read on page 15 about the specially designed camera that took the picture. What the beautiful image evokes is in the brain of the beholder. In my case, coral polyps brought to mind a hypothesis published in 1842 by Charles Darwin.One of the scientific goals of the first voyage of HMS Beagle was to explain how coral atolls form. The question was puzzling. Unlike Australia’s Great Barrier Reef or Central America’s Great Maya Reef, which are located in shallow coastal waters, coral atolls are found in the deep ocean. Corals grow upward from the seafloor. If the water is too deep, the photosynthetic algae that live within the polyps and supply their energy can’t get enough light to live.Darwin theorized that coral atolls grew in a ring-shaped zone around the sloping sides of marine volcanoes that had once risen above the sea. Over time, the seamount subsides and becomes submerged. The still-growing coral, however, continues to reach upward. If the sea level falls or if the seafloor lifts up, the uppermost part of the ring of coral is pushed up above the surface to create an atoll.One of the ingredients of Darwin’s atoll theory was the idea from James Hutton, Charles Lyell, and other geologists that Earth’s crust was shaped in the past by physical processes that continue to operate in the present. Some of the processes, such as earthquakes and volcanoes, are sudden and violent, whereas others, like the formation of mountain ranges or the transformation of marine sediment into rock, play out gently over eons.Darwin’s leap to consider how living things might have changed on similarly long time scales is one of the greatest feats of scientific imagination. What is perhaps less well known is that some of Darwin’s successors have tried to predict how Earth’s biosphere will fare billions of years into the future.In five billion years’ time the Sun will turn into a red giant whose outer envelope will expand to engulf Earth in few-thousand-degree plasma. Before that fiery fate, as helium fusion supplants hydrogen fusion as the star’s principal source of energy, the Sun will shine more brightly and Earth’s surface temperature will rise.The hotter the Earth becomes, the more vigorously the hydrological cycle will spin—up to a point. When water molecules reach the stratosphere, UV photons will split them, and the hydrogen atoms will escape into space, never to rain down on Earth again. At that point, Earth will have lost its surface water and our planet’s sterilization will be complete.But life could end before then. In a paper published in 1982, James Lovelock and Michael Whitfield recognized that on a warmer Earth the weathering of silicate rocks would accelerate.11. J. E. Lovelock, M. Whitfield, Nature 296, 561 (1982). https://doi.org/10.1038/296561a0 Metallic cations released into the environment would bind to atmospheric carbon dioxide to form carbonates. The CO2 that plants need to survive would be sequestered out of their reach. Earth’s biosphere, Lovelock and Whitfield estimated, would collapse within 100 million years.Ten years later Ken Caldeira and James Kasting published a more elaborate derivation22. K. Caldeira, J. F. Kasting, Nature 360, 721 (1992). https://doi.org/10.1038/360721a0 of the future atmospheric concentration of CO2. Besides certain feedbacks, they also took into consideration the fact that some species of plant, including maize, millet, and other food crops, use a carbon fixation pathway, C4, that is more resistant to heat than the C3 pathway used by trees and considered by Lovelock and Whitfield. According to Caldeira and Kasting, Earth’s biosphere will be dead within 1.5 billion years at the latest.The prospect that Earth’s atmospheric CO2 will dwindle to the point that all the planet’s plants die off might be taken as justification for doing nothing to curb humankind’s emission of greenhouse gases. Some climate skeptics might argue that burning more fossil fuels would even forestall that fate. It can’t. Earth has far more silicate rocks than coal, oil, and natural gas.Despite their grim prognostication, Caldeira and Kasting ended on an optimistic note. It should be encouraging to humans, they wrote, “because it implies that we could survive for geologically long time periods if we can manage to cope with our other societal problems.”REFERENCESSection:ChooseTop of pageREFERENCES <<CITING ARTICLES1. J. E. Lovelock, M. Whitfield, Nature 296, 561 (1982). https://doi.org/10.1038/296561a0, Google ScholarCrossref, ISI2. K. Caldeira, J. F. Kasting, Nature 360, 721 (1992). https://doi.org/10.1038/360721a0, Google ScholarCrossref, ISI© 2016 American Institute of Physics.

Millets and Herders: The Origins of Plant Cultivation in Semiarid North Gujarat (India)

Botanical evidence suggests that North Gujarat (India) was a primary center of plant domestication during the mid-Holocene. However, lack of systematic archaeobotanical research and significant taphonomic processes have so far hampered the possibility of substantiating this hypothesis. This paper explores the role of plants in the subsistence strategies of early-middle Holocene populations in this semiarid region and the processes leading to plant cultivation. To do so, we carry out a multiproxy archaeobotanical study—integrating macro and microbotanical remains—at two hunter-gatherer and agropastoral occupations. The results show that the progressive weakening of the Indian summer monsoon ca. 7,000 years ago compelled human populations to adopt seminomadic pastoralism and plant cultivation, which resulted in the domestication of several small millet species, pulses, and sesame.

Dry land millets: A review of its drought tolerance

Drought is one of the major abiotic stresses affecting plant growth and reducing crop productivity, which has been estimated to affect 70% of crop yield.Tolerance to abiotic stresses is very complex, due to the intricate of interactions between stress factors and various molecular, biochemical and physiological phenomena affecting plant growth and development. Millets are hardy plants capable of growing where most other grain cereals would fail. In the present review, strategies used to adapt to drought stress and the damages caused at physiological, biochemical and molecular level are described. This review also describes drought tolerant varieties and genes identified in millet species and their performance in transgenic crops. The tolerance exhibited by hybrids of drought resistant landraces and high yielding elite germplasm is also included. It is concluded that a combination of transgenic breeding, marker assisted breeding and conventional breeding will be necessary for imparting tolerance to combat drought in future.

Leaf Expansion and Transpiration Responses of Millet Species to Soil Water Deficit

Plant processes, such as leaf expansion, stomatal conductance and transpiration, are affected by soil water, particularly in water–stressed environments. Quantifying the effects of soil water on plant processes, especially leaf expansion and transpiration, could be useful for crop modeling. In order to quantify the leaf expansion and transpiration in response to soil water deficit in three millet species, common (Panicum miliaceum L.), pearl (Pennisetum glaucum L.) and foxtail (Setaria italica L.) millets, a pot experiment was performed at the Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. The soil water status was characterized by the fraction of transpirable soil water (FTSW). Leaf area and transpiration were measured daily. Relative leaf area expansion (RL) and relative transpiration (RT) data were plotted against FTSW. Finally the FTSW thresholds for RL and RT were calculated using linear–plateau and logistic models. The results showed that the thresholds for RL and RT were 0.68 and 0.62, respectively, based on all measured data of the three millet species using the linear–plateau model, indicating that RL and RT were constant when FTSW decreased from 1 to the threshold point. Thereafter, until FTSW = 0, RL and RT declined linearly with a slope of 1.48 and 1.43, respectively. Although millet is cultivated as a resistant crop in arid, semiarid and marginal lands, it showed an early response to soil water deficit at high FTSW thresholds. As leaf expansion and transpiration can be considered morphological and physiological variables, respectively, the results in this study indicate that millet has strong morphological flexibility when faced with soil water deficit.