Tuesday Lecture – Cereal Grains Reading: Textbook, Chapter 5 The topic of class for this week will be members of the grass family, which as cereal crops provide more than half of all calories that humans consume. Members of the family are used in many other ways by people, including as forage grasses for livestock.

McClung Museum Field Trip – Review - Reciprocal effects of agricultural on plants and people Plants – “pre-adapted” by weedy habit  domesticated People – changes to society structure: stratification ritual uses of plants/arts, medicine - High yield agriculture – supports more people, but at the cost of good health (Dr. Crites: when corn became widespread, human health “went down the crapper”) The word cereal is derived from the name of the Roman goddess of agriculture, Ceres, and refers to the edible grains produced by annual grasses. A grain is a 1-seeded fruit in which the fruit and seed wall are fused together. (The term grain is also used to refer to similar 1-seeded fruits of a few other food plants, such as grain amaranths and buckwheat, but these are not grasses.)

Quiz Briefly describe 2 things that you learned during the field trip to the McClung Museum During his discussion of New World agriculture, Dr. Gary Crites of the Museum staff mentioned several cereal crops that originated in the New World – name one of them (by scientific or common name) The word cereal is derived from the name of the Roman goddess of agriculture, Ceres, and refers to the edible grains produced by annual grasses. A grain is a 1-seeded fruit in which the fruit and seed wall are fused together. (The term grain is also used to refer to similar 1-seeded fruits of a few other food plants, such as grain amaranths and buckwheat, but these are not grasses.)

What is a Cereal? See Fig. 5.1, p. 111 The word cereal is derived from the name of the Roman goddess of agriculture, Ceres, and refers to the edible grains produced by annual grasses. A grain is a 1-seeded fruit in which the fruit and seed wall are fused together. (The term grain is also used to refer to similar 1-seeded fruits of a few other food plants, such as grain amaranths and buckwheat, but these are not grasses.) See Fig. 5.1, p. 111

What is a Cereal? Ceres – Roman goddess of agriculture (in Greek, Demeter). Myth: mother of Persephone, who was kidnapped by Hades; Ceres went on strike to demand return of daughter; Persephone had eaten a pomegranate seed  forced to divide time – explanation for temperate seasons The word cereal is derived from the name of the Roman goddess of agriculture, Ceres, and refers to the edible grains produced by annual grasses. A grain is a 1-seeded fruit in which the fruit and seed wall are fused together. (The term grain is also used to refer to similar 1-seeded fruits of a few other food plants, such as grain amaranths and buckwheat, but these are not grasses.) See Fig. 5.1, p. 111

What is a Cereal? Ceres – Roman goddess of agriculture (in Greek, Demeter). Myth: mother of Persephone, who was kidnapped by Hades; Ceres went on strike to demand return of daughter; Persephone had eaten a pomegranate seed  forced to divide time – explanation for temperate seasons Grain = seeds/seedlike fruits of plants, particularly grasses The word cereal is derived from the name of the Roman goddess of agriculture, Ceres, and refers to the edible grains produced by annual grasses. A grain is a 1-seeded fruit in which the fruit and seed wall are fused together. (The term grain is also used to refer to similar 1-seeded fruits of a few other food plants, such as grain amaranths and buckwheat, but these are not grasses.) See Fig. 5.1, p. 111

What is a Cereal? Ceres – Roman goddess of agriculture (in Greek, Demeter). Myth: mother of Persephone, who was kidnapped by Hades; Ceres went on strike to demand return of daughter; Persephone had eaten a pomegranate seed  forced to divide time – explanation for temperate seasons Grain = seeds/seedlike fruits of plants, particularly grasses Cereal = edible grains produced by annual grasses The word cereal is derived from the name of the Roman goddess of agriculture, Ceres, and refers to the edible grains produced by annual grasses. A grain is a 1-seeded fruit in which the fruit and seed wall are fused together. (The term grain is also used to refer to similar 1-seeded fruits of a few other food plants, such as grain amaranths and buckwheat, but these are not grasses.) See Fig. 5.1, p. 111

What is a Cereal? Ceres – Roman goddess of agriculture (in Greek, Demeter). Myth: mother of Persephone, who was kidnapped by Hades; Ceres went on strike to demand return of daughter; Persephone had eaten a pomegranate seed  forced to divide time – explanation for temperate seasons Grain = seeds/seedlike fruits of plants, particularly grasses Cereal = edible grains produced by annual grasses Cereal Grain – redundant? The word cereal is derived from the name of the Roman goddess of agriculture, Ceres, and refers to the edible grains produced by annual grasses. A grain is a 1-seeded fruit in which the fruit and seed wall are fused together. (The term grain is also used to refer to similar 1-seeded fruits of a few other food plants, such as grain amaranths and buckwheat, but these are not grasses.) See Fig. 5.1, p. 111

Poaceae (Gramineae) – Grass Family The grass family is very large in terms of numbers of species, although not the largest. It is, however, clearly the most important family for people both ecologically and economically, and its members are found throughout the land surfaces of the globe.

Poaceae (Gramineae) – Grass Family Gramineae – traditional name for family The grass family is very large in terms of numbers of species, although not the largest. It is, however, clearly the most important family for people both ecologically and economically, and its members are found throughout the land surfaces of the globe.

Poaceae (Gramineae) – Grass Family Gramineae – traditional name for family Ranks: 4th (number of species) 1st (Number of individuals) 1st – Economic Importance The grass family is very large in terms of numbers of species, although not the largest. It is, however, clearly the most important family for people both ecologically and economically, and its members are found throughout the land surfaces of the globe.

Poaceae (Gramineae) – Grass Family Gramineae – traditional name for family Ranks: 4th (number of species) 1st (Number of individuals) 1st – Economic Importance Agrostology – Study of Grasses The grass family is very large in terms of numbers of species, although not the largest. It is, however, clearly the most important family for people both ecologically and economically, and its members are found throughout the land surfaces of the globe.

Grass Plant – Overall Structure See Fig. 5.2, p. 112 Grass plants have a structure that is highly distinctive and different from most other plants – there are terms that refer to specific structures in grasses. The vegetative characteristics contribute to the usefulness of grasses.

Grass Infloresence Structure See Fig. 5.2, p. 112 Almost all grasses are wind-pollinated, and their flowers and inflorescences are modified for this purpose. The grass inflorescence consists of a series of bracts (modified leaves) that enclose the flowers. The structure of these bracts and connecting structures is used to identify different grasses and also contributes important elements to how they are used.

Grass Infloresence Structure See Fig. 5.2, p. 112 Flower Almost all grasses are wind-pollinated, and their flowers and inflorescences are modified for this purpose. The grass inflorescence consists of a series of bracts (modified leaves) that enclose the flowers. The structure of these bracts and connecting structures is used to identify different grasses and also contributes important elements to how they are used.

Grain – Fruit of the Grass Family See Fig. 5.4, p. 112 Grain – Fruit of the Grass Family Understanding the grain (1-seeded fruit) of the grass family is essential to discussion of food plants of the family. Most of the grain is occupied by a storage tissue, the endosperm. Endosperm is typically triploid, and arises from the second of the two fertilization events characteristic of flowering plants (double fertilization). The endosperm in grasses typically is packed with starch granules. The embryonic plant, also called the germ, contains proteins and oils – in many grains this is stripped away before the grain is used. The aleurone layer contains the enzymes that can start the reaction that changes starch into sugar, a key step in using grains for specialized uses such as brewing beer. The fused fruit and seed wall is rich in fibers – like the germ, it is often stripped away from the grain before it is used in food products.

Grain – Fruit of the Grass Family See Fig. 5.4, p. 112 Grain – Fruit of the Grass Family Understanding the grain (1-seeded fruit) of the grass family is essential to discussion of food plants of the family. Most of the grain is occupied by a storage tissue, the endosperm. Endosperm is typically triploid, and arises from the second of the two fertilization events characteristic of flowering plants (double fertilization). The endosperm in grasses typically is packed with starch granules. The embryonic plant, also called the germ, contains proteins and oils – in many grains this is stripped away before the grain is used. The aleurone layer contains the enzymes that can start the reaction that changes starch into sugar, a key step in using grains for specialized uses such as brewing beer. The fused fruit and seed wall is rich in fibers – like the germ, it is often stripped away from the grain before it is used in food products.

Grain – Fruit of the Grass Family See Fig. 5.4, p. 112 Grain – Fruit of the Grass Family Understanding the grain (1-seeded fruit) of the grass family is essential to discussion of food plants of the family. Most of the grain is occupied by a storage tissue, the endosperm. Endosperm is typically triploid, and arises from the second of the two fertilization events characteristic of flowering plants (double fertilization). The endosperm in grasses typically is packed with starch granules. The embryonic plant, also called the germ, contains proteins and oils – in many grains this is stripped away before the grain is used. The aleurone layer contains the enzymes that can start the reaction that changes starch into sugar, a key step in using grains for specialized uses such as brewing beer. The fused fruit and seed wall is rich in fibers – like the germ, it is often stripped away from the grain before it is used in food products.

Grain – Fruit of the Grass Family See Fig. 5.4, p. 112 Grain – Fruit of the Grass Family Understanding the grain (1-seeded fruit) of the grass family is essential to discussion of food plants of the family. Most of the grain is occupied by a storage tissue, the endosperm. Endosperm is typically triploid, and arises from the second of the two fertilization events characteristic of flowering plants (double fertilization). The endosperm in grasses typically is packed with starch granules. The embryonic plant, also called the germ, contains proteins and oils – in many grains this is stripped away before the grain is used. The aleurone layer contains the enzymes that can start the reaction that changes starch into sugar, a key step in using grains for specialized uses such as brewing beer. The fused fruit and seed wall is rich in fibers – like the germ, it is often stripped away from the grain before it is used in food products.

Grain – Fruit of the Grass Family See Fig. 5.4, p. 112 Grain – Fruit of the Grass Family Understanding the grain (1-seeded fruit) of the grass family is essential to discussion of food plants of the family. Most of the grain is occupied by a storage tissue, the endosperm. Endosperm is typically triploid, and arises from the second of the two fertilization events characteristic of flowering plants (double fertilization). The endosperm in grasses typically is packed with starch granules. The embryonic plant, also called the germ, contains proteins and oils – in many grains this is stripped away before the grain is used. The aleurone layer contains the enzymes that can start the reaction that changes starch into sugar, a key step in using grains for specialized uses such as brewing beer. The fused fruit and seed wall is rich in fibers – like the germ, it is often stripped away from the grain before it is used in food products.

Changes in Cereal Grasses through Domestication 1. Simultaneous tillering or elimination of branching Different cereal grasses all exhibit a common syndrome of changes relative to their wild progenitors that are a prerequisite for their effective use in agriculture. These include changes so that all of the inflorescences on the crop are ready for harvest at one time; thickening of the stems so that the inflorescences do not topple into the soil before harvest; changes so that the seeds are not separated for dispersal (and thus remain easily available to be harvested); and changes so that the grains will detach readily from the inflorescence and its bracts when the crop is harvested. See Fig. 5.5, 5.6, 5.7, 5.8, pages 114-115

Changes in Cereal Grasses through Domestication 1. Simultaneous tillering or elimination of branching Different cereal grasses all exhibit a common syndrome of changes relative to their wild progenitors that are a prerequisite for their effective use in agriculture. These include changes so that all of the inflorescences on the crop are ready for harvest at one time; thickening of the stems so that the inflorescences do not topple into the soil before harvest; changes so that the seeds are not separated for dispersal (and thus remain easily available to be harvested); and changes so that the grains will detach readily from the inflorescence and its bracts when the crop is harvested. Reduced lodging See Fig. 5.5, 5.6, 5.7, 5.8, pages 114-115

Changes in Cereal Grasses through Domestication 1. Simultaneous tillering or elimination of branching Different cereal grasses all exhibit a common syndrome of changes relative to their wild progenitors that are a prerequisite for their effective use in agriculture. These include changes so that all of the inflorescences on the crop are ready for harvest at one time; thickening of the stems so that the inflorescences do not topple into the soil before harvest; changes so that the seeds are not separated for dispersal (and thus remain easily available to be harvested); and changes so that the grains will detach readily from the inflorescence and its bracts when the crop is harvested. Reduced lodging Non-shattering See Fig. 5.5, 5.6, 5.7, 5.8, pages 114-115

Changes in Cereal Grasses through Domestication 1. Simultaneous tillering or elimination of branching Different cereal grasses all exhibit a common syndrome of changes relative to their wild progenitors that are a prerequisite for their effective use in agriculture. These include changes so that all of the inflorescences on the crop are ready for harvest at one time; thickening of the stems so that the inflorescences do not topple into the soil before harvest; changes so that the seeds are not separated for dispersal (and thus remain easily available to be harvested); and changes so that the grains will detach readily from the inflorescence and its bracts when the crop is harvested. Reduced lodging Non-shattering Free-threshing See Fig. 5.5, 5.6, 5.7, 5.8, pages 114-115

Major Cereal Crops SeeTable. 5.2, p. 110 Barley – Hordeum vulgare Wheat – Triticum (T. aestivum, T. monococcum, T. durum) Rye – Secale cereale Oats – Avena sativa Rice – Oryza sativa Sorghum – Sorghum bicolor Millets – Eleusine coracana, Pennisetum glaucum, etc. Corn – Zea mays Each major agricultural center included one or more cereal crops among its major food plants. We will discuss the major ones that are still widely cultivated today. Of these, corn, rice, wheat, and barley are by far the most important.

Barley – Hordeum vulgare First King of Cereals Archaeological evidence suggests that barley was one of the first cereals to be widely cultivated. It was later superseded by wheat as the most important cereal for human food in areas where it is grown, although it is still a very important crop.

Barley – Hordeum vulgare The wild forms of barley are “2-rowed” – there is only 1 fertile floret each in the two clusters of 3 spikelets each that occur at every node. A change so that all of the florets are fertile produced “6-rowed” barley that is more productive. Barley tends to be grown in cooler areas – either in the temperate zones or at higher elevations in the tropics. Origin: near East (Fertile Crescent) Uses: Bread, Beer, Livestock feed See Fig. 5.9, p. 116 6-rowed 2-rowed

Wheat – The Staff of Life Wheat is arguably the foundation on which western civilization is based. By about 4,000 years ago it had become the dominant cereal of the eastern Mediterranean region, and was carried from there around the globe. Twin “ears” of wheat are depicted on older editions of the U.S. penny coin. “Wheat penny”

Evolution of Wheat See Fig. 5.10, p. 117 Wheat has an interesting history that is still being unraveled by biologists, and involved several significant evolutionary changes. The first wheats to be brought into cultivation were diploid species, with 7 pairs of chromosomes. An early, spontaneous change occurred involving a wild species (whose identity is still not known with certainty) to produce tetraploid forms. The tetraploids were more useful than the diploids because of changes that made them easier to harvest and that increased the amounts of the gluten proteins in their grains. Glutens cause doughs made from wheat flour to become elastic when kneaded – an essential element in raised breads. Tetraploid wheats today are used to produce flours for macaronis and other pastas. A further polyploidization event occurred that involved addition of a genome from a related genus, Aegilops (goat grasses) to produce our hexaploid bread wheats. The implications and effects of polyploidy are still an area of active study, and are significant to breeding efforts to incorporate genetic material from related wild diploids into tetraploid and hexaploid wheats. See Fig. 5.10, p. 117

Types of Wheat Einkorn – relictual cultivation only Emmer, Durum (tetraploid) “hard” wheat – used for macaroni Spelt, Bread Wheat (hexaploid) “soft” wheat - bread flour Higher ploidy  higher gluten content (gluten – protein) The uses of different wheats are closely tied to the quality of proteins in their grains as well as their levels of productivity. The diploid wheats (einkorn) are not widely cultivated. Tetraploid wheats are used for macaroni and other pastas, and are grown in areas of low rainfall. Bread wheats (T. aestivum) are known only from cultivation, and are widely grown as a source of flour for bread. See Fig. 5.10, 5.11 p. 117 Einkorn Emmer Spelt Bread

Wheat and its Pests Wheat rust, Puccinia graminis, is a major fungal disease that is spread by spores. It is controlled by selection of resistant cultivars (lower left) Various diseases and pests have limited the cultivation of wheat in North America. Studies in plant pathology combined with breeding work are an important element of success in wheat production.

Rye – Secale cereale Weed or First Cereal Crop? Rye is another cereal crop of the near East region. Although rye is thought to have originated as a weed of wheat or barley fields, recent archaeological evidence suggests that it may be as old or older than either of these. Rye flour is an essentially component in the traditional “black breads” of northern European regions. Rye has the advantage of growing well in cold and dry habitats. It also contains larger amounts of lysine, an essential amino acid, than some other cereals. It is not as widely cultivated as wheat or barley, however. Standard Wisdom: originated as weed; better in cool climates New Finds: 13,000 year old rye, in Syria  3,000 years older than other cereals

Rye, Witches, and Triticale See Fig. 5.14, p. 119 Rye with ergot fungus Rye is susceptible to a fungus called ergot in which the rye spikelet is taken over by the fruiting body of the fungus (above left). The fungus contains chemical components related to the drug LSD that cause hallucinations if ingested in low amounts (and serious disease and even death in larger amounts). Ergot is more problematic in cold, wet years, and an association has been shown between the incidence of “witch” incidents in earlier times with climate, leading some to suggest that ingestion of contaminated rye flour is an element of the story of the perception of people as witches. A happier event was the production of an artificially created octoploid by hybridization of bread wheat with rye. This plant, called triticale, has the advantage if producing higher yields of grain with better lysine content than wheat in marginal grain-growing regions. It is still under development as a crop, and is mostly used as an animal feed. Wheat Rye Triticale – intergeneric hybrid

Oats – A Weed Becomes (Somewhat) Respectable Oats is the last major Eurasian grain crop to appear in the archaeological record, and it is thought to be have been originally a weed of other grains. It is best adapted to cool climates and was probably domesticated in northern Europe. Like wheat, polyploidy is involved in its development, and current cultivars are hexaploid. Its greatest applications are as an animal feed. Recently, attention has been devoted to the potential that oat bran has for reducing cholesterol – it is now regarded as one of several sources of “soluble fiber” that can play such a role. Origin – weed in barley or wheat Adapted to cool climates  animal feed Romans: Germans “oat-eating barbarians”

Oats Close Up See Fig. 5.15, p. 120 Oat Spikelet – Glumes + Florets Oats have fairly large and open spikelets in which the bracts and florets can be seen. The oat fruit has the typical structure of a grass grain. As in other grains, the part of the grain (primarily endosperm) left after removal of the hull (bracts), pericarp (bran) and embryo (germ) is called a groat – oat groats that are rolled or cut so that they cook readily are sold as oatmeal.

Rice – The World’s Most Important Crop See Fig. 5.18, p. 122 More people depend on rice as a primary food crop than any other grain. Rice was the major cereal crop of the Far East, and appears to have been domesticated in the Yangtze River area of China as long as 12,000 years ago.

Rice Close Up Rice has the typical vegetative and reproductive structures found in members of the grass family. Although traditionally rice was eaten as a whole grain (“brown rice”), modern technology has encouraged the consumption of polished rice, in which the pericarp and embryo (germ) are removed (together with their nutrients and vitamins). Loss of vitamins in rice processing is associated with the increase of the disease beriberi, which is caused by lack of vitamin B1.

Processing Rice The photos to the left and right, above, show views of mature rice ready for harvest. The difference between polished (left) and unpolished grains are shown at lower right.

Rice – Next Steps for the Green Revolution Rice – Genomic Research Golden Rice – Boon or Bane? Pro: solve problem (vitamin A deficiency) using biotechnology Con: problem originated with technology (polishing rice) and can be reversed; problems exist with technology (“Frankenfoods”; new gene combinations); increased reliance on agrobusiness Rice, together with wheat, have been the focus crops of the Green Revolution. Recently, however, the yield increases have lagged behind human population growth in areas where rice is a dominant crop for human consumption. The completion of a complete sequence of the rice genome, announced in January 2001, holds promise to lead to breakthroughs for higher yields. The release of Golden Rice, a cultivar that has been genetically modified to produce higher levels of vitamin A, has ignited controversy over various aspects of GM crops.

Sorghum Likes it Hot and Dry Origin: Ethiopia Sorghum, whose common name is the same as its scientific one, is native to tropical Africa and was brought into cultivation in Ethiopia. It has been subject to selection for various different uses, including both food and non-food ones, leading to numerous distinctive types.

Main Types of Sorghum Four main types: grain sorghums sweet sorghum (animal feed) Sudan grass (related species) broomcorn The grain sorghums are used for human food; the sweet sorghums for animal feed; Sudan grass is a forage crop; and broomcorn is used to make brooms. See Fig. 5.22, 5.24, p. 125

Millets – A Mixed Bag See Table 5.4, p. 126 Millet is a general term used to describe several small cereal grains. Several of these were domesticated in sub-Saharan Africa and are still important food crops in the region. Of these, finger millet and pearl millet are the most significant. Finger millet – Eleusine coracana Pearl millet – Pennisetum glaucum

Thursday Lecture – Corn Reading: Textbook, Chapter 5 On Tuesday we will consider Zea mays, the major cereal crop of the New World region.