Seedless Fruits and Vegetables Timeline

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VOLUME 5, ISSUE 2 SeedlessSeedless FFruitsruits and VegetablesVegetables

An Integrated Curriculum For The Washington Post Newspaper In Education Program

How and Why: Seedless Fruits and Vegetables Timeline

Lesson: Seedless fruits and and the life cycle of leaves. Go 4,000 to 5,000 years ago: Egyptian vegetables have been developed to www.washpost.com/nie and hieroglyphics depict farmers by scientists to improve existing in lessons plans select Leaves. harvesting watermelons. Gradually varieties, to create new varieties they spread throughout the and to meet consumer demands. Read About Seedless Watermelons Mediterranean region, popular as Level: Low to high Give students a copy of “How Do food and as nature’s bottled water. Subjects: Science, health, You Grow Seedless Watermelon?” language arts written by Post science reporter 10th century: Watermelons reach China Related Activity: Art, home Rick Weiss. The following ques- economics, economics tions may be used with the Oct. 13th century: Watermelons 25, 2005, KidsPost article. spread through Europe This online guide is related to • For how many years have a new series of science-focused people cultivated watermelons? 16th century: Watermelons appear KidsPost articles. Students ask • Why was the watermelon in North America, probably the questions, scientists and particularly useful in North arriving on slave ships from Washington Post science writers Africa and the Middle East? Africa and the Caribbean give the answers. In addition to • What evidence exists that suggesting activities for using watermelons were valued in Egypt? 20th century: Scientists create the KidsPost articles, sidebars, • How many seeds may be seedless watermelon varieties timelines, graphs and charts, found in a regular watermelon? activities are provided for older • In what country was the first 21st century: New colors? New students in related disciplines. seedless watermelon developed? flavors? Seeds that taste like M&Ms? Where might you find seedless How many years did this team What would you like to see? fruits and vegetables in the pages of scientists work on this project of The Washington Post? In Food before they were successful? section recipes that encourage the • What procedure was used to mix of feta and goat cheeses with develop seedless watermelon? watercress, chopped red tomatoes • Weiss makes a comparison of and diced seedless watermelon. In seedless watermelons to mules. Science articles in which reporters List the ways in which mules and introduce new varieties of seedless watermelons are not alike. In grapes and eggplants. In Business what ways are mules and seed- section pages, where seedless less watermelons alike? Explain tomato fruit sales are compared to to students that the pairs of an profits from older varieties. In the analogy do not need to share a Reliable Source where we learn that large number of similar charac- Jennifer Lopez’s contract “rider teristics or qualities. Those that a few years ago specified white they do share should be distinct. couches, white roses, white candles, • For what reasons did scientists honey-peanut butter Balance Bars work to develop seedless water- and green seedless grapes.” melons, according to the article? The suggested questions • What are the white specks and activities in this guide found in seedless water- include the same variety as melons? Are they edible? Post coverage and the classes • Give evidence that the found in students’ schedules. American consumer has accepted Teachers may also wish to use seedless watermelons. FILE PHOTO — THE WASHINGTON POST The Post NIE online guide Leaves Seedless watermelons are harvested on a that focuses on photosynthesis CONTINUED ON PAGE 3 farm in Maryland.

2 October 25, 2005 VOLUME 5, ISSUE 2

An Integrated Curriculum For The Washington Post Newspaper In Education Program

CONTINUED FROM PAGE 2 One to two class periods later, GLOSSARY ask students to write a poem, Some important words about plant breeding After reading the article and ode or short essay addressing discussing the questions, perhaps the fruit or vegetable. Are some Diploid students could sample a slice of a showing signs of decay more (DIP-loid) Having a pair of each type of seedless watermelon. No chance of than others? You may wish to chromosome a seed spitting contest beginning. cut into the fruit or vegetable to write a more analytic piece, DNA Describe Seedless Fruits a dissection of the produce. (short for deoxyribonucleic acid, which is and Vegetables pronouced de-OX-e RI-bo-nu-clay-ic acid). The Visit a farmer’s market or the Illustrate Produce famous basic strands of life. DNA carries coded produce section of a local grocery Use the display of fruits and information about what characteristics living things will pass on, in its unique ladder shape. store so students can become vegetables for an art project. acquainted with the colors, Whether the medium is oil, water- Chromosomes textures, sizes and shapes of fruits color, pastels, pencils or torn paper, (pronounced CROE-ma-somes) The parts of living and vegetables. If you cannot a display of fruits and vegetables cells that are made up of bundles of DNA and visit a farmer’s market, set up a can inspire still life compositions. protein inside cells. Chromosomes carry DNA’s display of grapes, eggplants, pump- Either before or after the exercise, code on genes. Human cells have 23 pairs of kins, squash and other fruits and you may share examples of still life chromosomes. Regular watermelon plants have 22 vegetables in the classroom. You artwork from different periods and pairs and seedless ones have 33 pairs. may decide to have all be seedless countries. The examples could illus- Gene or mix them and see if students trate single fruit subjects, combi- (JEAN) Genes are the basic unit of heredity. Traits, can discern which are seedless nations of fruits and vegetables, such as whether a watermelon has seeds or not, from the exterior appearance. different lighting and setups. are determined by the information carried in genes. Help students to understand Chromosomes can contain hundreds of genes. the importance of reading the How Do They Do It? labels provided by produce Give students the illustrated Genetics providers. Compare and contrast “How a Seedless Watermelon Is (je-NET-ix) The branch of science that studies how several items through informa- Made” page. Discuss the steps traits are passed on tion found on their labels. that lead to a seedless water- Heredity You may also name the melon. Use the glossary that (heh-RED-i-tee). Passing on biological traits or produce using foreign languages. is provided in this guide. characteristics from parents to offspring (including Watermelon, for example, would parent plants) by passing on genes be pastèque (French) anguria Research (Italian), suika (Japanese), sandia Seedless fruits and vegetables (Spanish) and lubenica (Croatian). have been developed for consumer Parthenocarpy Ask each student to select one consumption. These new and (PAR-th-no-kar-pe) The production of fruit without fruit or vegetable to describe: improved varieties offer a wide fertilization • using the five senses and color, range from which to select and to • using similes, research. Give students “Making Pollination • using comparison and contrast, Better Plants.” This reproduc- (POL-eh-na-shun) Transfer of pollen from an anther • using connotations. ible serves as a starting point to a stigma of the same flower for exploration of the seedless Store the item in a brown paper varieties that have been devel- Tetraploid bag, labeled with each student’s oped and some of the individuals (TET-ra-ploid) A cell having four chromosome sets name. One to two class periods who have been involved. later, ask students to write a story Give students “Not a Seedy in which the fruit or vegetable is a One in the Bunch.” This activity participant. Include a description of involves Internet research the produce in its current condition. CONTINUED ON PAGE 4

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An Integrated Curriculum For The Washington Post Newspaper In Education Program

CONTINUED FROM PAGE 3 tables (See “Not a Seedy One in the Bunch” or have them do some research Resources skills and the disciplines of science, to create the list). Students may be economics, and language arts. You divided into four groups to create the www.eurekalert.org may wish to include knowledge of following types of dishes. Each recipe EurekAlert the vocabulary terms found in the should use two or more seedless fruits This global news agency of sidebar of this guide. Questions that and/or vegetables. Remind students the American Association for the research will address include: to consider flavor and coloring in their the Advancement of Science • What is the history of and recipes; for example, seedless grapes (AAAS) is a clearinghouse for science behind the development of are white, red and black in color. news and the latest science seedless fruits and vegetables? Depending on your course, students information from universities, • What is the economic and may even be asked to prepare the medical centers, journals, environmental impact of the dishes according to their recipes. government agencies, research and development? Provide information on the nutri- corporations and other • What countries and scientists tional value of each dish. Class agencies engaged in research. have been involved in development? members could sample each dish. • What other fruits and vegetables Give an award for the best dish. www.usda.gov have the potential to be seedless? • Create a recipe for a dish to be U.S. Department of Agriculture EurekAlert has a section of news served at a formal dinner. Prepare or Articles, reports, research for kids. This site is a good starting illustrate a centerpiece for the table including growing and point for research on recent develop- using seedless fruits and vegetables. marketing of U.S. farm and ments and discoveries in science. • Devise a recipe for a dish to be ranch products. Begun in served at a family dinner. Prepare or 1862, the USDA was called Take it to the Bank draw a picture of the table setting. the “people’s Department” by Examine the economics involved in • Create a dessert recipe using two President Lincoln since “58 development of seedless fruits and vege- or more seedless fruits. Prepare or illus- percent of the people were tables. Areas of consideration include: trate the dessert as it would be served. farmers who needed good • Why would horticulturists want to • Create a brown bag lunch dish seeds and information to grow develop seedless fruits and vegetables? that students would enjoy eating and their crops.” This would include no requirement be healthy for them. Craft or draw to pollinate, reduced dependence a picture of the lunch bag and the www.mypyramid.gov on bees and warm weather. container that would hold the dish. My Pyramid • What costs are involved in U.S. Dept. of Agriculture breeding new varieties or improving What Else? educational material for older strains? What is involved 1. What novelty vegetables exist and elementary school teachers. in research and development? which would you like to breed? How Poster, lessons, worksheets • Who benefits from about carrots that are yellow, maroon and CD. marketing, distribution and avail- or red? They exist. What about fruits? ability of new varieties? Would you like blackberry bushes • What environmental benefits without thorns? They exist. Read about 3. Pretend that you are the maker and drawbacks are involved? them, then think of something new. of candy-coated raisins. Why might you be interested in the develop- Create a Recipe 2. Phytochemicals are natural ment of a sweet, seedless grape? Seedless fruits and vegetables are compounds that prevent disease. What presented in the finest restaurants, research is being done on modifying 4. Learn more about the U.S. served at family dinners and tucked the content of vegetables to contain Department of Agriculture into brown bag lunches. Give students more or some phytochemicals? What world seed collection. “Revisiting Melon.” This Post Food if certain diseases could be stopped section article and recipe inspired the or slowed and health improved by activity that follows. Provide students eating more of these new varieties? with a list of seedless fruits and vege-

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An Integrated Curriculum For The Washington Post Newspaper In Education Program How Do You Grow Seedless Watermelon? Think of seedless wwatermelonsatermelons as the mules of the vvegetableegetable kingdom. Mules araree what yyouou ggetet when a male donkdonkeyey mates with a female horhorse.se. Mules araree born sterile, which means they canncannotot makemake babies when they grgrowow up. The only wwayay to makmakee mormoree mules is to start ooverver with a donkdonkeyey and a horhorse.se. SeedlessSeedless wwatermelonsatermelons wworkork the ssameame wway.ay. They araree the offspring of twtwoo differdifferentent kinds of wwatermelonatermelon plants. These watermelonswatermelons araree healthy as a mule, not to mention swsweeteet anandd delicious.delicious. But liklikee mules, they cancan’t’t makmakee mormoree of themsethemselves.lves. The farmer or ggardenerardener must start frfromom scrscratchatch each yyear.ear. ScientistsScientists doing eexperimentsxperiments in JJapanapan made the firfirstst seedless wwatermelonsatermelons about 70 yyearsears agago.o. But in some ways,ways, they araree the fruit of 5,000 yyearsears of wwork.ork. That’That’ss hohoww long people hahaveve been grgrowingowing -- and grgraduallyadually imprimprovingoving -- watermelonswatermelons as part of an agage-olde-old human effeffortort to makmakee betbetterter foodsfoods thrthroughough the scientific specialty knoknownwn as plant brbreeding.eeding. Ancient varietiesvarieties werewere full of seeds. But with a waterwater content of about 92 perpercentcent they wwereere incrincrediblyedibly vvaluablealuable to nomads iinn the North African and Middle Eastern deserts, who used thethemm as naturnaturalal canteens. SSomeome Egyptian pharpharaohsaohs wwereere buried with wwatermelons,atermelons, to servservee as snacksnackss in the afterafterlife.life. EvenEven todatoday,y, rregularegular wwatermelonsatermelons hahaveve up to 1,000 seeds per melon.melon. That’That’ss grgreateat if yyou’reou’re in the mood to do some spitspitting,ting, but a hassle if yyouou wwantant to scarf dodownwn mouthfuls of sugsugary,ary, ruby rreded fflesh.lesh. ScientistsScientists had another rreasoneason to ggetet rid of the seeds: The softer tissue surrsurroundingounding the seeds is the firfirstst to ggetet mushy as a wwatermelonatermelon agages.es. A seedless wwatermelon,atermelon, they rreckoned,eckoned, wouldwould stastayy swsweeteet and frfreshesh longlonger.er. It took JJapaneseapanese scientists about 15 yyearsears of complecomplexx breedingbreeding eexperimentsxperiments to come up with a memelonlon that wwasas truly seedless. They did it by crcrossingossing twtwoo vvarietiesarieties with vveryery differentdifferent numbernumberss of chrchromosomes,omosomes, which araree the bundles of DNA inside cecells.lls. TTodayoday seedless vvarietiesarieties account fforor mormoree than half of all wwatermelonatermelon ssalesales in the United States. (Thos(Thosee littlelittle white thingthingss yyouou see araree the shrunkshrunkenen outer huskhuskss of the seeds that neneverver wwere,ere, and araree fine to eateat.).) SeedlessSeedless memelonslons araree ggenerallyenerally swsweetereeter than orordinarydinary memelons,lons, in part because all that enerenergygy that wwouldould hahaveve ggoneone into making seeds can instead ggoo into making sugsugar.ar. ImprovementsImprovements kkeepeep coming. A neneww vvarietyariety of seedless watermelonwatermelon is as small as a softball -- making it easy to pack iinn a lunch -- and has a rind thatthat,, although vveryery thin, is so strstrongong that thrthreeee 10-y10-year-oldsear-olds with vveryery ggoodood balance could stand on one without brbreakingeaking itit.. Which, come to think of itit,, could be as much fun as spitspittingting seeds. —By Rick Weiss 5 October 25, 2005 VOLUME 5, ISSUE 2

An Integrated Curriculum For The Washington Post Newspaper In Education Program Making Better Plants

Kids tend to look like their moms and dads, and the same rule applies to plants. The passing of traits from generation to generation is called heredity. And the field of science that focuses on the rules of heredity is called genetics. For thousands of years, farmers and gardeners have taken advantage of W the rules of heredity to create new Biology of a watermelon plants with bigger and sweeter Chromosome H O W fruits and with greater resistance to disease, drought and insect pests. Scientists who do this are called Y plant breeders. These scientists use pollen from the best male plants to fertilize the best female plants. They have brought DNA us big juicy ears of corn (varieties from several hundred Cell years ago were about the size of your thumb) and blackberry bushes that don’t have thorns. In recent years, scientists have learned how to make new plant varieties even more efficiently by “genetic engineering.” They insert or delete pieces of DNA, the genetic material that is packed inside a plant’s chromosomes. Among their results: corn plants that make insect-killing chemicals in their leaves, so farmers don’t have to spray them, and soybeans that will not die when farmers accidentally splash them with weed killers. But those advances bring new concerns too. Pollen from some of these plants has already spread accidentally to nearby weeds, making those weeds stronger. Scientists are now developing ways to keep new plant traits where they belong.

MEET A PLANT BREEDER thing!” she says. Of course, she adds, not Kim Lewers used to play around in every experiment works. Sometimes you her yard, sprinkling dust-like par- end up wth a fruit or a fl ower that’s worse ticles of pollen from one fl ower onto than what you started with. “That’s one another so new fl owers with novel of the fun things about it. You never know color combinations would pop up quite what you’ll get.” the next spring. She went on to get Here’s a helpful hint from Kim’s years of a graduate degree in plant breeding breeding fruits for better fl avor: If you’re and today she works for the Depart- picking strawberries or other fruits to eat, pick them around 4 in the afternoon. ment of Agriculture’s Fruit Labora- USDA tory in Beltsville, Maryland. Kim Lewers works for the “That’s when the fruit is producing the “Plant breeding is the greatest USDA’s Fruit Laboratory. most sugars,” she says.

6 October 25, 2005 How a Seedless Watermelon is Made

There are several ways to produce seedless fruits and vegetables. Many are an exception to the normal fertilization process. Creation of seedless watermelons requires seeds and pollination, and makes use of parthenocarpy. Picking it yourself? Four o’clock in the Plant breeders are busy as bees producing triploid and tetraploid seeds. afternoon is the best time to pick a watermelon (same with strawberries and other fruits). That’s when the sugar content is at its highest.

A plant breeder treats the seedling 1 of a normal (seeded) watermelon Scientifically speaking, watermelons with a few drops of a chemical. A normal watermelon has 22 are both fruits AND vegetables. The chromosomes. The chemical plants themselves are vegetables (their doubles that plant’s chromosomes closest relatives are squash, pump- to 44. kins and gourds) but the part you eat is the “fruiting body” (or reproduc- The seedling grows tive organ) of that vegetable plant. 2 into a plant whose 44x flowers have plant 44 chromosomes. Bees fertilize the plant with pollen from a normal, 22-chromosome watermelon plant. Seeds inside the resulting 22x watermelon have 33 chromosomes. plant

The watermelon seeds with 33 chromosomes are then planted. Bees take pollen from a normal They grow into 33-chromosome plants, which are tthehe ““mulesmules” 3 22-chromosome plant and pollinate the 44x of tthehe pplantlant kkingdom.ingdom. 33-chromosome watermelon plant 33-chromosome seeds plant. The watermelons 33x that grow are seedless. 33x plant Finally! plant WHEW!

33x plant VOLUME 5, ISSUE 2

An Integrated Curriculum For The Washington Post Newspaper In Education Program Not a Seedy One in the Bunch

You might have eaten seedless fruits Sure, it’s scary to find black widows At least three people found the in your lunch or on a picnic. Your on store-bought grapes. But food spiders on bunches of red seedless mother may be fond of using seedless safety specialists and growers say the grapes from California purchased vegetables in favorite recipes. You poisonous spiders are less frightening recently at separate Shaw’s might even find them mentioned in than the alternative: a return to harsher supermarkets in suburbs west of news articles such as one recent one pesticides. Boston. that reported:

You are about to become an expert on one seedless fruit or vegetable. Select one of the items listed below that can be bought in a seedless variety.

Apple Banana Cantaloupe Cucumber Eggplant (aubergine) Grapefruit Grapes (white, red, black) Green peppers Orange Pineapple Tangerine Tomato “Washington Navel” orange Watermelon

Your research should include the following: • What other fruits and vegetables have the • What is the history of and science behind the potential to be seedless using the same method? development of the seedless fruit or vegetable? Is • What is the environmental, economic, scientific research completed or still in the development stage? and cultural impact of the research, genetic • What countries and scientists have been involved engineering and development? in its development? • What scientific method, genetic modification or natural function was used in creating this seedless fruit or vegetable?

8 October 25, 2005 VOLUME 5, ISSUE 2

An Integrated Curriculum For The Washington Post Newspaper In Education Program Revisiting Melon

By Stephanie Witt Sedgwick Grilled slices can serve as an edible On a large plate, combine the base for poached fish. When diced, the Mexican seasoning and cinnamon. Every year we have a Fourth of July fruit mixes well in chicken, seafood and Dredge the shrimp in the seasonings, party, and every year someone brings a fruit salads. and set aside. watermelon. Some years it rains, some Cooked down, watermelon can enrich In a medium bowl, combine the years it’s clear. The guest list changes, glazes, barbecue sauces and be used to watermelon, pineapple, bell pepper, but the watermelon always shows up. sweeten all manner of things such as jalapeno pepper, if desired, and It’s been a sort of guessing game in iced tea. cucumber. Cover and refrigerate. our house to wager on who’s bringing For dessert, slices can be layered In a small bowl, whisk together the the melon. With the chicken frying, with sorbet to create an alternative “ice lime juice, soy sauce, honey and olive the salads made and brownies piled cream” sandwich or with fruit for a oil until well combined; set aside. high, one could say the watermelon has cakeless trifle. When ready to cook the shrimp, always been, well, unwelcome. Watermelon, our unwelcome guest, prepare the grill. If using a gas grill, This year, looking at the sugar baby might just turn out to be the life of the preheat the grill to medium-high. sitting on the counter, I decided to give party. If using a charcoal grill, start the it a second chance. The melon could charcoal or wood briquettes. When be sliced and placed on the buffet as Shrimp and Watermelon Salad the briquettes are ready, distribute always, but there had to be more to do 4 servings the heated charcoal evenly under the with it than that. Here, bites of watermelon taste great cooking area for direct heat. Be sure to After all, watermelon’s attributes go with shrimp that has a little heat. If you’d oil the grate with nonstick spray oil. beyond a cooling, thirst-quenching slice rather use a grill pan on the stove to cook Thread the shrimp onto the soaked of something on a hot summer night. the shrimp, skip the bamboo skewers. bamboo skewers and grill, turning once, Weight Watchers has recently been Adapted from Delicious Salad Meals, by Dot for 5 to 6 minutes or until the shrimp touting its nutritive benefits as a fat- Vartan (Dorothy Jean Publishing, 2005). are just opaque. Remove the shrimp free, low-calorie, vitamin- and mineral- from the skewers. packed food as well as its versatility as 2 tablespoons Mexican seasoning (may Divide the lettuce among individual an ingredient. It was time for another substitute a mixture of cumin, dried plates and place the shrimp and look. onion, chili pepper and garlic powder) watermelon mixture on the lettuce. It has vitamins C, A, B6 and thiamine 1 teaspoon cinnamon Drizzle the dressing on top, and as well as lycopene — as much as 1 dozen jumbo shrimp, peeled, sprinkle with the chopped cilantro. 40 percent more of this antioxidant. deveined and tails removed Serve immediately. According to the Agricultural Research 2 cups cubed, seeded watermelon Service, scientists have found that One 20-ounce can pineapple chunks, drained Per serving: 306 calories, 27 g protein, lycopene in the diet correlates with 1/4 cup diced green or yellow bell pepper 39 g carbohydrates, 7 g fat, 172 mg a reduced incidence of certain types 1 teaspoon finely chopped and seeded cholesterol, 1 g saturated fat, 481 of cancer. And lycopene levels in fat jalapeno pepper (optional) mg sodium, 5 g dietary fiber tissue — an indicator of lycopene 1/2 cup peeled and diceddiced seedless cucumber consumption — have been linked with 2 tablespoons fresh lime juice a reduced risk of heart attacks. 2 tablespoons low-sodium soy sauce Plus, one cup of watermelon contains 2 tablespoons honey a total of 48 fat-free calories. 1 tablespoon olive oil Once I got to thinking, the 8 cups torn romaine lettuce possibilities unfolded: 2 tablespoons chopped cilantro The fruit can be pureed for a refreshing drink, a summer soup or as HaveHave rreadyeady 8 bamboo skskewersewers that the basis for a low-fat salad dressing. havehave been thorthoroughlyoughly soaksoakeded in wwater.ater.

9 July 25, 2005