1663 Chapters
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34: Phytophthora infestans Population Changes in Kenya Pose Challenges to Existing Potato Blight Control Strategies



Phytophthora infestans Population

Changes in Kenya Pose Challenges to

Existing Potato Blight Control Strategies

M. Nyongesa,1* C. Lung’aho,2 L. Wasilwa,3 M. Mbiyu,1

J. Onditi1 and S. Otieno1


Kenya Agricultural and Livestock Research Organization (KALRO), Limuru,

Kenya; 2International Potato Center Sub-Saharan Africa (CIP-SSA),

Chimoio, Mozambique; 3KALRO, Nairobi, Kenya


Potato blight caused by Phytophthora infestans remains the leading biotic constraint to production of potato (Solanum tuberosum), the second most important food crop in Kenya. Until recently, the local population of P. infestans in Kenya was a typical US-1 clonal lineage of A1 mating type associated with the worldwide dispersal of the pathogen in the 1970s. Up to this point, blight management strategies were based on key phenotypic characteristics of the US-1 clonal lineage, namely fungicide sensitivity and virulence to the potato host. For example, although large-scale resistance to phenylamide fungicides

(e.g. metalaxyl) has been widely reported globally, field resistance to metalaxyl is yet to be reported in

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Medium 9780253006042

14 - Over The Mountains of the Moon

Simon J. Knell Indiana University Press ePub

“Over the Mountains

Of the Moon,

Down the Valley of the Shadow,

Ride, boldly ride,”

The shade replied –

“If you seek for Eldorado!”

“Eldorado” (1849)


IN THE MID-1980S, OUT OF SIGHT OF THOSE DEBATING THE meaning of the first Scottish animals, the next big step was being taken in a part of the world that had thus far proven itself completely lacking in these extraordinary fossils: South Africa. Here, along a dirt road in the Cedarberg Mountains, some two hundred kilometers north of Cape Town, Geological Survey officers Danie Barnardo, Jan Bredell, and Hannes Theron came across a new borrow pit for road metal exposing the soft and rarely seen Upper Ordovician Soom Shale.1 They stopped to investigate and found their curiosity rewarded with some intriguing fossils reminiscent of graptolites. Graptolites are one of those classic groups of extinct animals all paleontologists study at some point in their training. Tiny, colonial – bearing a passing resemblance to corals and bryozoans – their fossil remains are most common in shales, where they look like minute flattened saw blades. Theron sent a specimen to Barrie Rickards at Cambridge University in the UK, an expert on this group, to see if they really were graptolites. Rickards said they were not.

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Medium 9781603442909


Buster, Noreen A. Texas A&M University Press ePub

Impacts of Fluid and Gas Expulsion

Harry H. Roberts

Our understanding of the geology of the northern and northwestern Gulf of Mexico continental slope has taken a quantum leap forward since Fishery Bulletin volume 89 (Bulletin 89) was published in 1954. Single-trace echo-sounder profiling, single-point soundings, and data from coring, trawls, and grab samples formed the database from which most interpretations of continental slope geology were made. Less than a decade after World War II, seismic data were starting to be routinely acquired from marine settings, and attention was focused on the Gulf of Mexico because it was a proven hydrocarbon-producing province. Salvador (1991) indicated that the first offshore seismic-reflection survey was in 1944. Since then, the petroleum industry, government (U.S. Geological Survey), and academic groups (particularly the Institute for Geophysics, University of Texas) have acquired seismic-reflection data from throughout the Gulf. These surveys have been instrumental in establishing the geologic framework for the Gulf basin since little direct geological data were available for most of the deep Gulf. It was not until the 1960s to 1970s that adequate seismic-reflection and refraction data became available to define the geology of the deep Gulf as a thick sedimentary unit overlying an acoustic basement consisting of oceanic crust or transitional crust (Buffler 1991).

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Medium 9780253002358

19 Creationist Makeovers

Rudolf A. Raff Indiana University Press ePub

By the 1960s the scene had shift ed again. The shock of America being beaten into space by the Russian launch of Sputnik I, the first artificial satellite ever placed in orbit, thrust the quality of our science versus their science into the hysteria of Cold War rhetoric. On the plus side, the Sputnik debacle at least prompted thinking about a renewal in public school science education. I know that I benefited from the boom in science education funding that followed. The creationists, once so loud, had vanished from the public eye in the years following the Scopes Trial, because they had for all practical purposes won and no longer needed to be active. Publishers had cooled creationist fervor by letting evolution slip away from school textbooks. Nevertheless, creationists lay like dormant termites within the walls of American life. When new curricula and high school biology texts eventually restored the teaching of evolution as a fundamental idea of biology, creationism reappeared in fully energized righteousness.

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3: Development of Dual-purpose Sweetpotato Varieties through Participatory Breeding in Rwanda



Development of Dual-purpose

Sweetpotato Varieties through

Participatory Breeding in Rwanda

D. Shumbusha,1* J. Ndirigwe,2 L. Kankundiye,2

A. Musabyemungu2 and R.O.M. Mwanga3


Rwanda Agriculture Board (RAB), Huye, Rwanda;


RAB, Kigali, Rwanda; 3International Potato Center Sub-Saharan

Africa (CIP-SSA), Kampala, Uganda


Sweetpotato forms a major part of the diet of both rural and urban communities in Rwanda. Moreover, it is expected that the crop could become more important than it is already now, especially for farmers operating in mixed crop-livestock systems. The interest in sweetpotato as an animal feed is associated with the implementation of a policy regarding zero grazing practices as one of the ways to reduce soil erosion. This research was conducted to develop dual-purpose sweetpotato varieties through a participatory approach, using an accelerated breeding scheme. Sixty parents comprising local cultivars and introduced germplasm were used in a crossing block to generate true seeds. In total, 5380 well-established genotypes were selected from the seedling nursery and planted in an observational trial at Rubona,

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Medium 9780253012821

15 Visible Time

John Sallis Indiana University Press ePub




Not many leaves have yet fallen. Most are still green, even if beginning to show fringes of orange and yellow. Yet there are already a few trees that have donned their fall colors, displaying them brilliantly on days that are bright and clear, attesting visibly to the arrival of the season. Though the sun now stays a bit lower in the sky and the character of the light is noticeably different from that of summer, there is still, on bright, clear days, more than ample sunlight to let the blaze of color appear in all its radiance. Though the light itself seems more transparent than ever, the shining of color that its presence releases is unmatched by any other that nature has to offer. With the arrival of these bright, clear autumn days, it is as if the glorious yellows, oranges, and reds had been held in store throughout the summer, as if they had been carefully prepared by nature to announce the advent and then the progress of the new season. Within a couple of weeks the color will have reached its high point, and only the evergreens will have escaped nature’s brush entirely. Yet by then the leaves will also have begun to fall.

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17 What are the Factors that Dictate the Choice of Coping Strategies for Extreme Climate Events? The Case of Farmers in the Nile Basin of Ethiopia

Fuhrer, J.; Gregory, P.J., Editors; Fuhrer, J.; Gregory, P.J. CAB International PDF


What are the Factors that Dictate the Choice of Coping Strategies for Extreme Climate Events? The

Case of Farmers in the Nile

Basin of Ethiopia

Temesgen Tadesse Deressa

Guest Scholar, Africa Growth Initiative, Global Economy and

Development, Brookings Institute, Washington, DC, USA

17.1 Introduction

Droughts in Ethiopia can reduce household farm production by up to 90% of a normal year’s output (World Bank, 2003) and lead to the death of livestock and humans. The recorded history of drought in Ethiopia dates back to 250 bc. Since then, droughts have occurred in different parts of the country at different times (Webb and von

Braun, 1994). Studies show that the frequency of drought has increased over the past few decades, especially in the lowlands

(Lautze et al., 2003; NMS, 2007). In addition to drought, floods and hailstorms also reduce yields significantly during excessively rainy seasons.

In response to these natural calamities, farmers in Ethiopia have developed different coping strategies. Several studies have identified the primary coping strategies employed by farmers during extreme climate events, especially drought. The country-level study conducted by the Ministry of Finance and Economic Development (MoFED, 2007) on the ability of farmers to cope with shocks revealed that the main coping strategies included the sale of animals, loans from relatives, the sale of crop outputs and cash savings. A study by Belay et al. (2005) revealed that arid and semi-arid pastoralists in Ethiopia temporarily migrated, adopted

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Medium 9781845939946

7: Mites and Plant Damage

Vacante, V. CABI PDF

7   Mites and Plant Damage

Pest mites sensu stricto belong to the Tetranychoidea and

Eriophyoidea, both of which have mouthparts that are able to pierce plant tissues and suck out their contents. Other mite groups (Acaridae, Erythraeidae, Penthaleidae, etc.) have dif­ ferent mouthparts that are not strictly adapted to phytophagy, but are nevertheless also able to cause severe damage. The feeding mechanism, together with the plant response, determine the damage typology. Plant damage by mite pests has been

­extensively investigated in the Tetranychoidea and Eriophyoidea, but less so in the Tarsonemidae and other minor phytophagous groups. Sometimes, the symptoms can be easily taken for boron deficiency, or they may be confused with virus symptoms or even with herbicide action, such as on the new leaves of papaya infested by the broad mite, Polyphagotarsonemus latus (Banks).

The main part of this chapter is devoted to an account of the damage to plants that is caused by the main phytophagous groups of mites (Tetranychoidea, Eriophyoidea) and others

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Medium 9781603444750

14. Bobwhites and Other Wildlife

Hernández, Fidel Texas A&M University Press ePub

Figure 14.1. Brush is an important component of white-tailed deer habitat. It provides not only a dependable source of food but also important thermal and escape cover. (Photograph by David G. Hewitt)

THOUGH A NOBLE and valuable bird, the bobwhite is not the only important wild animal in cattle country. Sportsmen and sportswomen spend thousands of hours hunting whitetails, a species that raises hundreds of millions of dollars for landowners and merchants and increases the value of Texas real estate by millions. Wild turkeys provide countless hours of recreation in fall and spring. The opening of mourning dove season is no less important than spring break or Super Bowl weekend to many people. Likewise, Texas is blessed with untold numbers of nongame animals that enrich our lives and attract tourist dollars. Ecotourism such as birding and nature photography has become a billion-dollar industry.

Many people want to manage for several species of wildlife. Indeed, hunting leases are more valuable to lessor and lessee alike if there are high populations of more than one game species. People practicing “broad-spectrum” management will surely have questions about the recommendations in this book. How does bobwhite management affect deer? Turkeys? Doves? Nongame species? How does the management of these species affect bobwhites? This chapter addresses these questions.

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Medium 9781780646688


Hall, H.K.; Funt, R.C. CABI PDF


Blackberries: An Introduction

Kim E. Hummer*

U.S. Department of Agriculture, Agricultural Research Service,

National Clonal Germplasm Repository, Corvallis, Oregon, USA

What was known as a favorite seasonal specialty fruit crop for many in the northern hemisphere can now be purchased in grocery stores throughout the year. What was historically gathered from the wild in Europe and North America has expanded into commercial cultivation and is now available globally.

Enhanced germplasm is providing a wealth of traits to create new growth and production opportunities. New cultivars have been developed with unusual qualities and great changes in crop production have occurred recently.

In addition, production regions have expanded internationally in areas where innovative methods must be used to produce a crop for commercial production.

Classification and Distribution

Blackberries are members of Rubus subgenus Rubus (previously called subgenus Eubatus), while raspberries, their close relatives, are grouped in Rubus subgenus Idaeobatus. From a horticultural standpoint, each blackberry fruit is an aggregation of drupelets. Each drupelet is derived from one ovary that produces one hard-coated seed (pyrene). The seed is incased in a fleshy mesocarp with a surrounding exocarp (fruit skin). The drupelets are attached to a receptacle (torus). When the fruit is ripe, the drupelets remain attached to the receptacle, breaking away (dehiscing) from the stem (petiole) as a single unit ready for consumption. In contrast, the drupelets of raspberries separate from the receptacle. Raspberry drupelets are held together by small hairs and form a hollow, edible ‘cap.’

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Medium 9781780641645

1 Introduction

Ziska, L.H., Editor; Dukes, J.S., Editor CAB International PDF



Jeffrey S. Dukes1 and Lewis H. Ziska2


of Forestry and Natural Resources & Department of

Biological Sciences, Purdue University, West Lafayette, Indiana,

USA; 2Crop Systems and Global Change Laboratory, USDA-ARS,

Beltsville, Maryland, USA

As we write this, the global population has reached 7.1 billion. At present rates, approximately 5 million new individuals will be added each month, every month, for the foreseeable future. (www.census.gov/ popclock).

Ultimately, it is our rapidly increasing population and our need to increase the production of food, feed, fibre and fuel from a finite set of natural resources that are driving the environmental issues in this book, and that give these issues urgency. We need to transition to a sustainable society if we are to provide for this population (or even a smaller one) into the future. Such sustainability is necessary if we are to preserve our planet’s ecosystem services, maintain its capacity to produce food and protect its biodiversity.

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Medium 9781780641935

7 Crop Protection: Pest and Disease Management

Heuvelink, E. CABI PDF


Crop Protection: Pest and Disease


Gary E. Vallad, Gerben Messelink and Hugh A. Smith


According to the Food and Agriculture Organization (FAO) of the United

Nations (FAOSTAT database), nearly 177 million metric tons (t) of tomatoes were produced globally from 4.8 million hectares in 2016, an average yield of

37 t of tomatoes for every hectare of land in production throughout the world.

The level of tomato production throughout the world demonstrates the cultural importance of this New World vegetable (see also Chapter 1). The efficiency of tomato production, represented here as the average yield of fruit per hectare of land, varies greatly throughout the world, ranging from 1.5 t/ha for Somalia to

650 t/ha for greenhouses in The Netherlands. This vast discrepancy is further illustrated by the fact that Somalia produces tomatoes on an estimated 11,200 ha of open field production, compared with only 1750 ha of mostly greenhouse production in The Netherlands (FAOSTAT database). It is logical to assume that much of the discrepancy in production efficiency observed globally is directly related to the level of key inputs that have become standard for modern agriculture, including infrastructure (irrigation systems and protected structures), machinery, fertilizer and the assorted pesticides utilized for the management of weeds, pests and diseases. It is paramount that food production keeps up with global population growth; and an expanding middle-class population in many developing areas of the world is likely to increase the demand for tomatoes.

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Hall, H.K.; Funt, R.C. CABI PDF


Soil and Water Management

Richard C. Funt1,* and David S. Ross2


Ohio State University, Columbus, Ohio, USA; 2University of Maryland,

College Park, Maryland, USA


Each grower must intelligently weigh certain fundamentals in site and soil selection that are important for the success of a blackberry production unit. A farm may grow different crops for different markets, and therefore requires a management plan for the location of the infrastructure for the water supply and how water is to be applied to different soil types and different crops. A site should be chosen with the soil characteristics needed for the best long-term blackberry production (Slate et al., 1949) (see Chapters 8 and 9).

An effective management plan should include the future expansion of the business in regards to water usage, movement of vehicles across main irrigation lines, size of irrigation equipment, and the rotation and/or expansion of crops. These need to be oriented to the type of production and marketing system that the grower selects. In general, the grower needs to have both longterm and short-term economic planning horizons to be effective and efficient with an operation. Soil and water management over the short and long term is very important.

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Geologic History of the Gulf of Mexico

Buster, Noreen A. Texas A&M University Press ePub

Dale E. Bird, Kevin Burke, Stuart A. Hall, and John F. Casey

The formation of the Gulf of Mexico basin was preceded by the Late Triassic breakup of Pangea, which began with the collapse of the Appalachian Mountains (ca. 230 Ma; Dewey 1988). Gondwanan terranes of the southern part of the Gulf States, eastern Mexico, and the Yucatan Peninsula remained sutured onto the North American continent as it drifted away from the African-Arabian-South American continent (or Residual Gondwana, Burke et al. 2003). Early seafloor spreading in the central Atlantic Ocean, from about 180 Ma to 160 Ma, included 2 jumps of the seafloor-spreading center to new locations. The timing of the latter ridge jump (ca. 160 Ma) correlates with initial rifting and rotation of the Yucatan block.

The Gulf of Mexico ocean basin is almost completely bounded by continental crust. Its shape requires that at least one ocean-continent transform boundary was active while the basin was opening (Fig. 1.1). Evolutionary models differ between those that require the basin to open by rotation along a single ocean-continent transform boundary (counterclockwise rotation of the Yucatan block), and those that require the basin to open by rotation along a pair of subparallel ocean-continent transform boundaries (essentially northwest-southeast motion of the Yucatan block). Although many models have been proposed, most workers now agree that counterclockwise rotation of the Yucatan Peninsula block away from the North American Plate, involving a single ocean-continent transform boundary, led to the formation of the basin; many of these workers suggest that this rotation occurred between 160 Ma (Oxfordian) and 140 Ma (Berriasian-Valanginian) about a pole located within 5 of Miami, Florida (Humphris 1979; Shepherd 1983; Pindell 1985, 1994; Dunbar and Sawyer 1987; Salvador 1987, 1991; Burke 1988; Ross and Scotese 1988; Christenson 1990; Buffler and Thomas 1994; Hall and Najmuddin 1994; Marton and Buffler 1994). Evidence cited for this model of basin evolution includes: (1) paleomagnetic data from the Chiapas massif of the Yucatan Peninsula (Gose et al. 1982; Molina-Garza et al. 1992), (2) fracture zone trends interpreted from magnetic data (Sheperd 1983; Hall and Najmuddin 1994), (3) non-rigid tectonic reconstructions (Dunbar and Sawyer 1987; Marton and Buffler 1994), and (4) kinematic reconstructions making use of geological constraints, well data, and geophysical data such as seismic refraction, gravity, and magnetics (Pindell 1985, 1994; Christenson 1990; Marton and Buffler 1994).

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7 Evaluating the Dinosaur Track Record: An Integrative Approach to Understanding the Regional and Global Distribution, Scientific Importance, Preservation, and Management of Tracksites

Daniel Ma Edited by Peter L Falkingham Indiana University Press ePub

7.1. The Dinosaur Track Road in Teruel (Spain) footprint sites.

Evaluating the Dinosaur Track Record: An Integrative Approach to Understanding the Regional and Global Distribution, Scientific Importance, Preservation, and Management of Tracksites


Luis Alcalá, Martin G. Lockley, Alberto Cobos, Luis Mampel, and Rafael Royo-Torres

MANY PAPERS ON FOSSIL TRACKS, FROM MANY REGIONS of the world have been published in the last two decades, and this rapid increase in documentation has itself generated the idea of a dinosaur “footprint renaissance” marked by a landslide of new discoveries and documentation. Many of these papers mention the significance of these sites in terms of selected variables such as size of site, number of tracks, new or unknown ichnotaxa, new stratigraphic or geographic occurrence, trackmaker behavioral implications, and so forth. However, the significance of fossil tracksites is often not comprehensively discussed or evaluated in such a way as to address all relevant criteria and facilitate comparison with other sites. In this chapter we describe an approach for evaluating tracksites.

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