Wheat Growth and ManagementSource from FAODownload and organized by: Li ShaochangJan,24, 2005
Wheat Growth and Management Source from FAO Download and organized by: Li Shaochang Jan, 24, 2005
CONTENTSChapter1.Wheatintheworld.Chapter 2.Botany of the wheat plant..MATUREPLANTTHESEED,GERMINATIONANDSEEDLINGEMERGENCROOTS8SHOOTAPEXDEVELOPMENTLEAVES.10THECULM14TILLERING15THE EAR.1721Chapter 3. Wheat growth and physiologyWHEATDEVELOPMENT2128WHEATGROWTHWHEATPHYSIOLOGYANDABIOTICSTRESS.3446Chapter 4. Management of irrigated wheat..46WHEATENVIRONMENTS47IRRIGATEDWHEATCROPPINGSYSTEMS.48CULTURALPRACTICES..56OPTIMUMANDSUSTAINABLEIRRIGATEDPRODUCTIONSYSTEMS..58Chapter5.Nitrogenmanagementin irrigated springwheat..APPROACHESTO IMPROVING NITROGEN-USEEFFICIENCY INIRRIGATED58WHEAT...74Chapter6.Harvestand storage managementofwheat.74HARVESTTECHNIQUES..STORAGETECHNIOUES76CROPCULTIVARSRESISTANTTOSTORAGEINSECTDAMAGE.8111
ii CONTENTS Chapter 1. Wheat in the world. 1 Chapter 2. Botany of the wheat plant . 4 MATURE PLANT .4 THE SEED, GERMINATION AND SEEDLING EMERGENCE.5 ROOTS .7 SHOOT APEX DEVELOPMENT .8 LEAVES.10 THE CULM.14 TILLERING .15 THE EAR.17 Chapter 3. Wheat growth and physiology . 21 WHEAT DEVELOPMENT.21 WHEAT GROWTH .28 WHEAT PHYSIOLOGY AND ABIOTIC STRESS.34 Chapter 4. Management of irrigated wheat . 46 WHEAT ENVIRONMENTS .46 IRRIGATED WHEAT CROPPING SYSTEMS .47 CULTURAL PRACTICES.48 OPTIMUM AND SUSTAINABLE IRRIGATED PRODUCTION SYSTEMS .56 Chapter 5. Nitrogen management in irrigated spring wheat. 58 APPROACHES TO IMPROVING NITROGEN-USE EFFICIENCY IN IRRIGATED WHEAT .58 Chapter 6. Harvest and storage management of wheat . 74 HARVEST TECHNIQUES.74 STORAGE TECHNIQUES.76 CROP CULTIVARS RESISTANT TO STORAGE INSECT DAMAGE.81
Chapter1.WheatintheworldB.C.CurtisThe cultivation of wheat (Triticum spp.) reaches far back into history. Wheat was oneof the first domesticated food crops and for 8 o00 years has been the basic staple food ofthe major civilizations of Europe, West Asia and North Africa. Today,wheat is grown onmoreland areathananyothercommercial crop andcontinuesto bethemostimportantfood grain source for humans. Its production leads all crops, including rice, maize andpotatoes.Although the crop is most successful between the latitudes of 30° and 60°N and 27°and 40°s (Nuttonson, 1955), wheat can be grown beyond these limits, from within theArctic Circle to higher elevations near the equator. Development research by theInternational Maize and Wheat Improvement Center (CIMMYT) during the past twodecades(SaundersandHettel.1994)hasshownthatwheatproductioninmuchwarmerareasistechnologicallyfeasible.Inaltitude,thecropisgrownfromsealeveltomorethan3000masl,and ithasbeen reported at4570masl inTibet (Percival, 1921).Theoptimumgrowing temperature is about 25°C, with minimumand maximum growthtemperatures of 3°to 4°C and 30°to32C,respectively (Briggle, 1980).Wheat is adaptedto a broad range of moisture conditions from xerophytic to littoral. Although aboutthree-fourths of the land area where wheat is grown receives an average of between 375and 875 mm of annual precipitation, it can be grown in most locations where precipitationranges from 250 to 1750 mm (Leonard and Martin, 1963).Optimal production requires anadequate source of moisture availability during the growing season; however, too muchprecipitation can lead to yield losses from disease and root problems. Cultivars of widelydiffering pedigreearegrown undervaried conditions of soil and climateand show widetraitvariations. Although wheat is being harvested somewhere in the world in any given month,harvestinthetemperate zones occursbetweenApril andSeptemberintheNorthernHemisphere and between October and January in the Southern Hemisphere (Percival,1921)Classification into spring or winter wheat is common and traditionally refers to theseasonduringwhichthe cropisgrown.Forwinterwheat, heading isdelayeduntiltheplantexperiencesaperiodofcoldwintertemperatures(0°to5C).Itisplantedintheautumntogerminateanddevelopintoyoungplantsthatremaininthevegetativephaseduringthewinterandresumegrowthinearlyspring.Thisprovidestheadvantageof usingautumnmoisture for germination and making effective use of early spring sunshine, warmth andrainfall.Spring wheat, asthename implies,is usuallyplanted inthespringandmatures inlatesummerbut can besown in autumn in countriesthatexperiencemild winters,such asinSouthAsia,NorthAfrica,theMiddleEastandthelowerlatitudes.Wheat is special in several ways. Wheat is grown on more than 240 million ha, largerthan for any other crop, and world trade is greater than for all other crops combined. Theraised bread loaf is possible because the wheat kernel contains gluten, an elastic form ofprotein that traps minute bubbles of carbon dioxide when fermentation occurs in leaveneddough, causing the dough to rise (Hanson et al., 1982). It is the best of the cereal foods and
1 Chapter 1. Wheat in the world B.C. Curtis The cultivation of wheat (Triticum spp.) reaches far back into history. Wheat was one of the first domesticated food crops and for 8 000 years has been the basic staple food of the major civilizations of Europe, West Asia and North Africa. Today, wheat is grown on more land area than any other commercial crop and continues to be the most important food grain source for humans. Its production leads all crops, including rice, maize and potatoes. Although the crop is most successful between the latitudes of 30° and 60°N and 27° and 40°S (Nuttonson, 1955), wheat can be grown beyond these limits, from within the Arctic Circle to higher elevations near the equator. Development research by the International Maize and Wheat Improvement Center (CIMMYT) during the past two decades (Saunders and Hettel, 1994) has shown that wheat production in much warmer areas is technologically feasible. In altitude, the crop is grown from sea level to more than 3 000 masl, and it has been reported at 4 570 masl in Tibet (Percival, 1921). The optimum growing temperature is about 25°C, with minimum and maximum growth temperatures of 3° to 4°C and 30° to 32°C, respectively (Briggle, 1980). Wheat is adapted to a broad range of moisture conditions from xerophytic to littoral. Although about three-fourths of the land area where wheat is grown receives an average of between 375 and 875 mm of annual precipitation, it can be grown in most locations where precipitation ranges from 250 to 1 750 mm (Leonard and Martin, 1963). Optimal production requires an adequate source of moisture availability during the growing season; however, too much precipitation can lead to yield losses from disease and root problems. Cultivars of widely differing pedigree are grown under varied conditions of soil and climate and show wide trait variations. Although wheat is being harvested somewhere in the world in any given month, harvest in the temperate zones occurs between April and September in the Northern Hemisphere and between October and January in the Southern Hemisphere (Percival, 1921). Classification into spring or winter wheat is common and traditionally refers to the season during which the crop is grown. For winter wheat, heading is delayed until the plant experiences a period of cold winter temperatures (0° to 5°C). It is planted in the autumn to germinate and develop into young plants that remain in the vegetative phase during the winter and resume growth in early spring. This provides the advantage of using autumn moisture for germination and making effective use of early spring sunshine, warmth and rainfall. Spring wheat, as the name implies, is usually planted in the spring and matures in late summer but can be sown in autumn in countries that experience mild winters, such as in South Asia, North Africa, the Middle East and the lower latitudes. Wheat is special in several ways. Wheat is grown on more than 240 million ha, larger than for any other crop, and world trade is greater than for all other crops combined. The raised bread loaf is possible because the wheat kernel contains gluten, an elastic form of protein that traps minute bubbles of carbon dioxide when fermentation occurs in leavened dough, causing the dough to rise (Hanson et al., 1982). It is the best of the cereal foods and
providesmorenourishmentforhumansthananyotherfood source.Wheat isamajordietcomponent because of the wheat plant's agronomic adaptability,ease of grain storage andease of converting grain into flour for making edible, palatable, interesting and satisfyingfoods.Doughsproducedfrombreadwheatflourdifferfromthosemadefromothercerealsin their unique viscoelastic properties (Orth and Shellenberger, 1988).Wheat is the mostimportantsourceofcarbohydrateinamajorityofcountries.Wheatstarchiseasilydigestedasismostwheatprotein.Wheatcontainsminerals,vitaminsandfats(lipids),andwithasmall amount of animal or legume protein added is highly nutritious.A predominatelywheat-baseddiet ishigherinfibrethanameat-baseddiet(Johnsonetal.,1978)(sauro ro uonenod600500(ey uogiu) ealy400.Area300Production2001000电名-YearsFigure1.1Worldwidewheatareaandproduction(Source:CIMMYT,1996.)Wheat is also a popular source of animal feed, particularly in years where harvests areadversely affected by rain and significant quantities of the grain are made unsuitable forfood use. Such low-grade grain is often used by industry to make adhesives, paperadditives,severalother productsand even intheproductionof alcohol.Wheat-producingcountriesChina has the largest land area devoted to wheat production, followed closely by theUnited States,IndiaandtheRussianFederation.KazakhstanandCanada,rankingfifthand sixth, produce wheat on about half the area of the top four countries. In recent years,Chinawith an averageproduction ofmore than100million tonnes annually ranks faraheadof the United States andIndia,each averagingnear 6o million tonnes.Productionincreases inChinahavebeendramaticinrecentyears;productionin1995was3percenthigher than in1994.Among the larger land area producers, China's yield was 3.5 tonnes/ha, while theUnited States, India and Russian Federation produced 2.5, and 1.5 tonnes/ha,respectively
2 provides more nourishment for humans than any other food source. Wheat is a major diet component because of the wheat plant’s agronomic adaptability, ease of grain storage and ease of converting grain into flour for making edible, palatable, interesting and satisfying foods. Doughs produced from bread wheat flour differ from those made from other cereals in their unique viscoelastic properties (Orth and Shellenberger, 1988). Wheat is the most important source of carbohydrate in a majority of countries. Wheat starch is easily digested, as is most wheat protein. Wheat contains minerals, vitamins and fats (lipids), and with a small amount of animal or legume protein added is highly nutritious. A predominately wheat-based diet is higher in fibre than a meat-based diet (Johnson et al., 1978). Wheat is also a popular source of animal feed, particularly in years where harvests are adversely affected by rain and significant quantities of the grain are made unsuitable for food use. Such low-grade grain is often used by industry to make adhesives, paper additives, several other products and even in the production of alcohol. Wheat-producing countries China has the largest land area devoted to wheat production, followed closely by the United States, India and the Russian Federation. Kazakhstan and Canada, ranking fifth and sixth, produce wheat on about half the area of the top four countries. In recent years, China with an average production of more than 100 million tonnes annually ranks far ahead of the United States and India, each averaging near 60 million tonnes. Production increases in China have been dramatic in recent years; production in 1995 was 3 percent higher than in 1994. Among the larger land area producers, China's yield was 3.5 tonnes/ha, while the United States, India and Russian Federation produced 2.5, and 1.5 tonnes/ha, respectively. Figure 1.1 Worldwide wheat area and production (Source: CIMMYT, 1996.)
World tradeAlthough most wheat is consumed within the country where it is produced, roughlyone-fifthof the annual cropis exported.Worldwheattradewasestimatedat 108 milliontonnesin1995,mostofwhichwasimportedbydevelopingcountries.Despiteincreaseinproductionduringthepastthreedecades,developingcountriesaccountfortwo-thirdsofallwheat imports, which is up from less than half in 1961. China, the world's largest wheatproducer,isalsotheworld'slargestwheat importer,averagingmorethan10milliontonnesannually since 1980 (CIMMYT,1996).Other countries importing more than 5million tonnesannuallyincludetheRussianFederation,Egypt,JapanandBrazil.The United States,Canada,Franceand Australia continue tobe the largest exportingcountries, ranging from 32.7 to 10.2 million tonnes, respectively.Except for France, thewheatimportedfromthesehigh-incomecountries is usuallyaqualityproductpurchasedtosupplement and enhancethe use-potential of locally grown wheat. Canada is consideredan important source of high-quality,high-protein wheat for importing countries.The UnitedStates produces a widerange of hard andsoft wheat possessinggrain protein ranging from7to8percent insoftwheatto19to20percent inhardwheats(Johnsonetal.,1978)WheatutilizationWorld wheat utilization or consumption, defined as food, feed, seed and processeduses, as well as waste, has remained near 550 million tonnes since 1990.Consumptionworldwidehas increased rapidly since the early1960s.Wheat consumption indevelopingcountries rose 35 percent during the period 1963-1976. This primarily resulted fromincreasedurbanizationandanassociatedshiftintastesandpreferencestowheatoverriceand coarse grains, such as maize and sorghum. Also important was the increased adoptionof wheat as a food in countries that had consumed little wheat in the past. The influence ofurbanizationonwheatconsumptionwas mostclearlyseen insub-SaharanAfricawherepercaput consumptiongrowthrates in thelate1970sandearly1980sexceeded6percentannually.Annualconsumptiongrowthratesinthoseareashavenowdeceleratedtonearzero orless,while averageper caputconsumption remains near1okg/year.Urbanconsumers tend to prefer convenience-type foods that require little or no preparation(Curtis, 1982). From the mid-1980s to the present, the annual growth of wheatconsumption in all developing countries has decelerated from about 5 percent toless than2 percent. In high-income countries with mature food wheat markets, changes inconsumption take place slowly over time and aredriven by population growth and changingdietary preferences (CIMMYT,1996)
3 World trade Although most wheat is consumed within the country where it is produced, roughly one-fifth of the annual crop is exported. World wheat trade was estimated at 108 million tonnes in 1995, most of which was imported by developing countries. Despite increase in production during the past three decades, developing countries account for two-thirds of all wheat imports, which is up from less than half in 1961. China, the world’s largest wheat producer, is also the world’s largest wheat importer, averaging more than 10 million tonnes annually since 1980 (CIMMYT, 1996). Other countries importing more than 5 million tonnes annually include the Russian Federation, Egypt, Japan and Brazil. The United States, Canada, France and Australia continue to be the largest exporting countries, ranging from 32.7 to 10.2 million tonnes, respectively. Except for France, the wheat imported from these high-income countries is usually a quality product purchased to supplement and enhance the use-potential of locally grown wheat. Canada is considered an important source of high-quality, high-protein wheat for importing countries. The United States produces a wide range of hard and soft wheat possessing grain protein ranging from 7 to 8 percent in soft wheat to 19 to 20 percent in hard wheats (Johnson et al., 1978). Wheat utilization World wheat utilization or consumption, defined as food, feed, seed and processed uses, as well as waste, has remained near 550 million tonnes since 1990. Consumption worldwide has increased rapidly since the early 1960s. Wheat consumption in developing countries rose 35 percent during the period 1963-1976. This primarily resulted from increased urbanization and an associated shift in tastes and preferences to wheat over rice and coarse grains, such as maize and sorghum. Also important was the increased adoption of wheat as a food in countries that had consumed little wheat in the past. The influence of urbanization on wheat consumption was most clearly seen in sub-Saharan Africa where per caput consumption growth rates in the late 1970s and early 1980s exceeded 6 percent annually. Annual consumption growth rates in those areas have now decelerated to near zero or less, while average per caput consumption remains near 10 kg/year. Urban consumers tend to prefer convenience-type foods that require little or no preparation (Curtis, 1982). From the mid-1980s to the present, the annual growth of wheat consumption in all developing countries has decelerated from about 5 percent to less than 2 percent. In high-income countries with mature food wheat markets, changes in consumption take place slowly over time and are driven by population growth and changing dietary preferences (CIMMYT, 1996)