1. Starchy Staples

2. Starchy Staples Most plants store food reserves in the form of starch
Often these reserves are stored in underground organs
Some types of roots or modified stems

3. Starchy Staples Potato, sweet potato and cassava among top ten crops
All are tropical in origin but grown extensively in temperate areas today

4. Starchy Staples All propagated asexually
Highly productive > many tons per acre
Food insurance against some disasters such as fire, typhoons, or hail
High in carbohydrates, mostly starch, but low in protein and fat

5. Modified stems Variety of functions.
some specialized for asexual reproduction
some specialized for food storage
some for both
Available for renewed growth upon the return of favorable weather conditions
Modified stems, like erect stems, have recognizable nodes and internodes.

6. Stolons or runners
Above ground horizontal stems that produce buds and roots at the nodes
These buds develop into new plantlets
Area can be quickly invaded through this method of vegetative reproduction

7. Rhizomes Underground horizontal stems
Roots form all along the underside
Buds found at nodes can give rise to new plants
Rhizome may also be a food storage organ

8. Tubers Enlarged storage tips of a rhizome White potato is a tuber
"Eyes" of the potato are actually buds located at the nodes, and each bud can give rise to a new plant

9. Bulbs and corms Modified stems found in monocots
Bulbs are erect underground stems with both fleshy and papery leaves - food is stored in the fleshy leaves -- onions
Bulbs themselves can multiply
Corms store food reserves in the stem --no fleshy leaves -- taro
Corms can multiply

10. Storage roots
Tuberous roots modified fibrous roots that become fleshy and enlarged with food reserves -- sweet potato
can also function in asexual reproduction
Tap roots are food storing organs for biennial plants such as carrots, rutabagas, and turnips

11. WHITE POTATO Solanum tuberosum
Member of the family Solanaceae, Nightshade Family
Other members are tomato, eggplant, pepper, nightshade, and other poisonous plants

12. South American origins
Archeological evidence shows that 8000 years ago indigenous people living in the Andes Mts. collected wild potatoes (in what is now Peru)
At some point the potato became the staple food crop for the people in this area
When the Spanish conquered Peru in the 1530's, the potato was the staple of the Inca civilization spread over thousands of miles

13. Introduction to Europe
Potato introduced to Spain sometime during the middle to late 16th century
Potato cultivation slowly spread throughout Europe - only accepted as a food for humans in the 18th century
Lots of misinformation - Other members of the family known to be poisonous or hallucinogenic
Tuber is the only part safe to eat; all the above ground parts are poisonous

14. Potato in Ireland Readily accepted in Ireland
Established crop as early as 1625
Dietary staple for the Irish peasant throughout the 18th and the first half of the 19th century
Climate and soil ideal for the potato
Even small plot could feed a family

15. Ireland
Potato was so successful that it led to population increase - from 1.5 million to 8.5 million between 1760 and 1840
The poor subsisted on potatoes, some milk, and only occasionally fish or meat
Estimates - average adult consumed between 8 to 12 pounds of potatoes each day

16. Phytophthora infestans
Fungus causes the disease late blight of potato
Fungus attacks and destroys the leaves and stem causing them to blacken and decay in a short time and stopping tuber growth
Tubers are also attacked and rot in the ground or even later in storage
In cool wet weather, the fungus can kill a plant within a week.

17. Late blight disease in Europe
First appeared in Europe in 1844
Accidentally carried with new varieties of potato from Central or South America
First appeared in Ireland in August of 1845

18. Irish potato famine
Disease struck several times during the period of 1845 to 1849
Widespread destruction of the potato crop led to devastating famines among the Irish
Over one million died from starvation or from diseases that followed the famine
1.5 million Irish emigrated to other area- especially the United States, resulting in a 25-30% decline of the population

19. Potato in rest of Europe
Widely grown in Europe because it was encouraged by the aristocracy as a cheap food for the peasants
By the end of 18th century potato gained widespread acceptance throughout Europe
Potato blight devastated the crops in Europe but effects were not as severe as the Irish famine since the potato was not the sole dietary staple

20. Potato in the United States
Potato made its appearance in North America through the European colonies
There is some doubt as to the exact date of introduction 1621? or 1719?
Confusion in historical records between the white potato and the sweet potato
Word potato stems from the Arawak Indian word batata which actually referred to the sweet potato

21. United States today U.S. production about 5% of the world total
Potatoes grown in virtually every state
Top producing states are Idaho, Washington, and Maine
One-third of U.S. harvest consumed fresh
One-half is processed to make frozen French fries, potato chips, dehydrated flakes, and other products including potato starch.

22. Processed potatoes
Nothing new - Peruvian people from high in Andes Mts have made chuno, a freeze-dried dehydrated potato, for about 2000 years
Tubers are spread on the ground when a heavy frost is expected
Following freezing, the potatoes thaw during the day and are trampled to get rid of water - repeated until completely dried
Chuno can be stored for several years without spoiling

23. Solanum tuberosum Solanum, a large genus with over 2000 species
Member of the Solanaceae or nightshade family
Almost 6000 cultivars but most commercial growers plant a limited number of varieties
In the U.S, 12 account for 85% of the potato harvest

24. The potato plant
Bushy herbaceous annual with an alternate arrangement of large pinnately compound leaves - does best in cool climates
Two types of stems are produced
ordinary stems with leaves
underground rhizomes which end in tubers
Anatomically, the tuber is a modified version of a dicot stem

25. Potato cultivation
Propagated by "seed potatoes" - small pieces with at least one eye
Produces plants genetically identical to the parent and maintains the desired traits within a cultivar
Seed potatoes produced by farmers who specialize in growing only seed potatoes

26. Asexual reproduction
Advantages - faster and produces plants with desired qualities
Disadvantages - genetically identical plants share the same susceptibility to adverse environmental conditions and diseases
Most of the potatoes in Ireland were genetically identical - derived from one or two plants introduced into the country
A monoculture is always risky

27. Four familiar cultivars
Round white is an all purpose potato good for boiling, baking, or processing into chips, fries, or flakes
Russets (Idahos) elongate cylindrical tubers have a corky russet-colored skin and mealy texture - excellent baking potatoes and ideal for French fries
Round reds and long whites usually sold as new potatoes - harvested earlier in the growing season and have a very thin skin

28. Nutrients in potatoes
Rich in carbohydrates (about 25% of the fresh weight); parenchyma cells within the pith are filled with starch grains.
Low in proteins (only 2.5%) but good protein quality
Fat free - no cholesterol
Good source of vitamins, minerals, and fiber (which occur in the periderm)

29. Return of Late Blight
Late blight of potato has remained a major pathogen for both potato and tomato
Various fungicides developed to control the fungus
New strains of fungus have recently evolved that are resistant to the effective fungicides
Late blight once again poses a major threat for cultivation of potatoes

30. Sweet potato - Ipomoea batatas
Storage root
Vine in the morning glory family
Propagated vegetatively from “slips”
Requires a long, warm, growing season
Susceptible to chilling injury

31. Discovered by Columbus
Discovered on first voyage
Introduced to Spain on his return,
About 50 years earlier than the introduction of the white potato
Arawak peoples in Caribbean called it batata corrupted into the word potato
Originally “potato” was Ipomoea batatas but Solanum tuberosum later called that

32. Sweet potato
Following the introduction Widely grown in Spain and other Mediterranean countries
Considered a delicacy in Europe
Rumored to be an aphrodisiac, a claim that was later transferred to the white potato along with the name

33. Sweet potato Native to tropical South America
Cultivation several thousand years in Peru
Widely grown as a staple crop in Central America and tropical South America
During this same period also cultivated in several Pacific Islands and New Zealand
An earlier introduction by early seafaring natives? or natural dispersal of seeds?
Thor Heyerdahl's traveled from Peru to Polynesia in the reed raft Kon Tiki in 1947

34. Sweet potato today
Significant crop throughout the tropics and expanded to warm temperate regions
Used as livestock feed as well as an important food staple
China dominates the world's production
Important in several African countries
In the United States primarily grown in the South often called “yams”

35. Nutrition Rich in carbohydrates and certain vitamins and minerals -
Especially good sources Vitamin A and C
Some of the carbohydrates are present in the form of sugar
About 50% more calories than white potatoes but slightly less protein

36. Cassava - Manihot esculenta
Tuberous root - member of the spurge family (Euphorbiaceae)
Many names: manioc, tapioca, yuca
Vital food for millions in the tropics
Ranks fourth as a source of calories for humans in tropical countries
Tapioca pudding only familar cassava product in US.

37. Origin and spread of cassava
Origins in South America, probably Brazil;
May have been independently domesticated in Central America
Well established crop in the New World tropics long before the arrival of the Europeans

38. Cultivation today Brazil leading producer in South America
Portuguese introduced cassava into West Africa in the 16th century
Extensively cultivated in Africa today
Asia, especially Thailand and Indonesia, closely follows Africa in annual production with South America a distant third

39. Botany
Tall shrub with numerous tuberous roots that are similar in appearance to sweet potatoes but usually much larger

40. Propagation Propagated by stem cuttings - none of the root is used
Growth is fairly rapid and little care is needed following planting
Can also be cultivated from seed which can be a source of new genetic varieties
Roots harvested from 8 mos to 2 years

42. Environmental tolerance
Tolerant to a wide range of moisture and soil conditions
From hot lowerlands to cool highlands
Requires well drained soils to prevent root rot.
Tolerate extended dry periods ( up to 6 mos)
Resistant to many insects and fungal pathogens

43. Processing
Once harvested, roots subject to rapid decay and must be dried or processed by 24 hrs
Sweet or bitter varieties based on the concentration of poisonous hydrocyanic acid (HCN)
If not removed, this toxin can cause death by cyanide poisoning

44. Cyanogenic glycosides
The HCN is liberated by the action of enzymes upon cyanogenic glycosides present in cassava
Distinction between the sweet and bitter varieties is the concentration of the toxins
Environmental conditions are known to influence the production of cyanogenic glycosides

45. Removing the toxins
Sweet varieties with low HCN levels can be eaten with little preparation; peeling followed by boiling, steaming, or frying
Bitter varieties must undergo extensive preparation to detoxify before eating
Traditional methods of treating the peeled bitter roots vary and include drying, soaking, boiling, grating, draining, and fermenting, or combinations

47. Traditional preparation
In South America, the traditional preparation produces a meal called farinha
Peeled roots are grated and squeezed through a long cylindrical woven basket known as a tipiti
One end of the tipiti is tied to a tree while the other end is tied to a pole which is used to stretch the tipiti, thereby expressing juice from the grated pulp

49. Cassava Bread
Grated cassava meal is used to prepare a flat bread

50. Nutrients
Starch is the main nutrient - approximately 30% of the fresh weight
Very low in protein (1% or less) and
Can result in kwashiorkor - among peoples who rely on cassava exclusively

51. Other uses of cassava
Asia and the Americas also used for animal feed and for commercial starch production
Cassava starch has many applications in the food, textile, paper, and pharmaceuticals
Tapioca pudding made by cooking tapioca pearls with milk, eggs, sugar, and vanilla
The pearls are partly gelatinized cassava starch made by heating moist cassava flour in shallow pans

52. Yams - Dioscorea spp. True yams - Tuber crop
Important staples in many areas:
West Africa, southeast Asia, Pacific Islands, and Caribbean Islands
Genus has several hundred species of which ten are major food sources
Yams have been cultivated for over 5000 years in tropical Africa.

53. Yams
Tubers vary from size of potatoes to massive ones often weighing over 80 lbs
Prepared in ways similar to potatoes
20% starch with about 2% protein
Medically the tubers were an important source of sapogenins, a type of steroid used to make human sex hormones and cortisone

54. Taro - Colocasia esculenta
Corm (underground storage stem)
Member of the Araceae or arum family
Related to and resembles elephant's ears
Poi - the traditional dish of the native Hawaiians prepared from taro
Foods are also wrapped and cooked in the leaves during a Hawaiian feast or luau

55. Preparation
Corms are steamed, mashed, made into a dough, and allowed to ferment to prepare poi
Taro may also be cooked in ways similar to potatoes or processed into flour, chips, and breakfast foods
Nutritionally - around 25% carbohydrate, 2% protein and very little fat

56. Bananas Good source of energy since it’s rich in starch
Some converted to sugar as the fruit ripens
Good source of potassium

57. Bananas: the starchy fruit
Important dietary staple for millions in tropical countries
Bananas are true fruits
Starchy plantains are traditionally cooked and eaten as a vegetable
Africa leader in plaintain production
Cultivation of sweet banana greatest in Central America

58. Origin and early domestication
Native to southeast Asia
Among the first cultivated plants in area
Polynesians spread the banana throughout the Pacific islands
Cultivated in India for at least 2500 years

59. Spread of banana
Arabian traders introduced bananas into parts of Africa about 2000 yrs ago
Word "banana" comes from West Africa
Portuguese and Spanish colonizers spread bananas throughout tropical regions
Early in the 16th century they were introduced to the New World
Became established very early

60. Early 20th century
United Fruit Company (and other companies) developed extensive banana plantations in Central America along with corporate-run railroads and steamships
For 50 yrs United Fruit exerted control over the economies and governments of several countries - "banana republics"
Rise of nationalism starting in the 1950s led to the decline of United Fruit

61. Botany of banana
Produced by various species in the genus Musa in the Musaceae, the banana family.
Most cultivars are sterile triploids
Need tropical climate and constant moisture
Cultivated for the fruit, the fiber or even the foliage which is often used to wrap foods

62. Banana plant Often called a tree but large herbaceous monocot
May be 20 ft or more in height
"Trunk" not woody but is actually a rosette of overlapping, tightly packed leaf bases which arise from an underground corm.
Large leaves

63. Fruit production
Apical meristem converts from vegetative growth to flowering
Single monoeocious inflorescence develops
Flowering stalk contains 5 to 13 groups of flowers (often called hands or bunches)
Most groups contain female flowers that develop parthenocarpic fruit
Male flowers confined to the end of the inflorescence

64. Fruit Production

65. Propagation Fruit production ends the life of a plant
New suckers develop from the corm
Since the fruits are seedless these suckers are used in vegetative propagation
Suckers reach maturity in 9 to 12 months

66. Starchy Staples
Starchy staples are an important source of food for people in every area of the world
These starchy staples as well as many of the starchy grains are also grown for many non-food uses as well

67. Other uses for starch Adhesives Sizings (fillers or coatings)
cardboard, paper bags, gums for envelopes and stamps
Sizings (fillers or coatings)
manufacture of paper, cloth, thread, and yarn
strengthen the material, impart a smooth finish, or prepare the surface for dyes
Pharmaceutical industry as a binding and coating
Laundry starch
Production of sugar-based sweeteners
The fermentation by yeast produces alcohol

68. Summary
Modified stems and storage root function as food reserves, for asexual reproduction, and storage
Starchy staples include some of the world's foremost crops and play major roles in the human diet
Potato pivotal to developing societies from the ancient Incas in South America to the pre-industrial countries of Europe, especially 19th century Ireland