eChapters

Key facts

    
•    Though water is the most widely occurring substance on earth, freshwater accounts for only 2.5% whereas the rest of water is saltwater. The agriculture sector uses more than 75% of freshwater available. 
    
•    The current observed climate change impacts on water resources include increased precipitation at high latitudes and temperate areas, decreasing precipitation at low latitudes; decreasing snow covers, and glaciers in most regions; decreasing flows in some river basins; floods and droughts in some countries and significant decreases in lake and river size in Africa.
    
•    A number of climate models projected that a doubling of atmospheric concentrations of CO₂ would increase global precipitation by at least 5%.  The precipitation is expected to increase in some areas, such as, at high latitudes and in the tropics (south east monsoon regions and over the tropical Pacific), whereas the precipitation is likely to decrease in the sub-tropics (e.g. much of North Africa and northern Sahara).

Key Facts
    
•    The United Nations Framework Convention on Climate Change (UNFCCC) defines ‘climate change’ as a ‘Change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods’.
    
•    The main green house gases (GHG) that have caused the global climate change or global warming are carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (NO₂).
    
•    CO₂ is the principal anthropogenic greenhouse gas that affects the Earths radiative balance. It is the reference gas against which other GHGs are measured and therefore has a Global Warming Potential (GWP) of 1. CH₄ and N₂O have a GWP of 21 and 310 respectively.
    
•    CO₂ is responsible for most of the enhanced green house effect of more than 50%, CH4 about 10 to 15% and NO2 about 4%.
    
•    The global atmospheric concentrations of carbon-dioxide, methane and nitrous oxide have increased since 1750, CO₂ increased from a pre-industrial value of 280 ppm to 379 ppm in 2005, CH₄ increased from 715 ppb to 1774 ppb and NO₂ increased from 270 ppb to 319 ppb in 2005.

Key facts
        
Agriculture and livestock
    
·    The Intergovernmental Panel on Climate Change (IPCC) defines adaptation as ‘adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderates harm or exploits beneficial opportunities’. The adaptation can be considered as tackling the effects of climate change, whereas mitigation is tackling the cause of climate change such as reducing the sources or enhancing the sinks of greenhouse gases. There could be different types of adaptation such as autonomous (spontaneous) and planned adaptation (policy decision).
    
·    Autonomous adaptation includes altering varieties and/or species those are more appropriate to the altered thermal regime or with increased resistance to heat shock and drought; altering the timing or location of cropping activities; altering fertilizer rates to maintain grain or fruit quality consistent with the climate and altering amounts and timing of irrigation and other water management practices; diversifying income by integrating other farming activities such as livestock raising, integrated agriculture and aquaculture/fish farming; development and use of varieties and species resistant to pests and diseases, wider use of technologies to ‘harvest’ water, conserve soil moisture (e.g. crop residue retention) and to use water more effectively in areas where rainfall is projected to decrease and using seasonal climate forecasting to reduce production risk.

Key facts
    
·    The Food and Agriculture Organization (FAO) defines food security as a ’situation that exists when all people, at all times, have physical, social and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life’. There are four dimensions of food security: Food Availability (availability of sufficient food for all people at all times, i.e. production); Food Accessibility (physical and economic access to food at all times, i.e. affordability), Food Utilization (access to food that is nutritious, safe and produced in environmentally sustainable ways, i.e. nutrients in food and food safety); and Food Stability (reliability of adequate food supply).
    
·    Agriculture is important for food security since it provides food for the people and is the primary source of livelihood for 36% of the world’s total workforce. In the heavily populated countries such as Asia and the Pacific, about 40% to 50%, and in sub-Saharan Africa, about two-thirds of the working population make their living from agriculture.
    
·    Agriculture, livestock and fisheries production are all sensitive to climate and are affected by its changes. Climate change will increase hunger and malnutrition, emergence of new pests and diseases and will threaten fishing and aquaculture industries.

Key Facts
        
Agricultural food
    
·    There are multiple pathways through which climate-related factors may impact food contamination and food safety, food quality, foodborne diseases including changes in temperature and precipitation patterns, increased frequency and intensity of extreme weather events, ocean warming and acidification and changes in the transport pathways of complex contaminants.
    
·    All or most foodborne pathogens and their associated diseases are linked to changing environmental conditions, the notable of which are campylobacteriosis, salmonellosis and vibriosis.
    
·    An estimated 30% of reported cases of salmonellosis across much of continental Europe have been attributed to warm temperatures, especially when they exceed a threshold of 6°C above average. Likewise both in Australia and Canada a positive correlation was found between increasing temperature and incidence of salmonellosis.
    
·    Zoonosis such as Rift Valley Fever (RVF), West Nile Fever, tick-borne diseases and non-zoonotic animal diseases such as Blue tongue, African horse sickness, African swine fever are examples of animal diseases whose distribution is expected to be strongly influenced by climate change and variability.
    
·    Mycotoxin is a toxic secondary metabolite produced by filamentous fungi, commonly known as moulds and may contaminate agricultural commodities (food) by growing on them both before and after harvest, whenever the humidity and temperature are permissive. The most prominent mycotoxins are aflatoxins, deoxynivalenol, zearalenone, ochratoxin-A, fumonisin, and patulin.
    
·    The humans ingestion of mycotoxins occur through consumption of the mycotoxin contaminated plant-based foods, such as grains, maize, barley, rice, coffee, nuts and their residues, and metabolites in animal-derived foods, for example aflatoxin M1 (AFM1) in milk and meat products. In addition, mycotoxins may occur in beer and wine.

Key facts

Agriculture
    
·    Agriculture production (plant growth) is highly dependent on climate since crop growth is influenced by solar radiation, temperature and precipitation and sensitive to climate variability and weather extremes (droughts, floods, severe storms).
    
·    Climate change is projected to have an effect on local agriculture and the net result could be harmful (e.g. frequent droughts, salinization of agriculture land due to sea level rise) or beneficial, (e.g. enhance CO₂ and higher yield, longer growing season, increased precipitation) or mixed.
    
·    Climate change or a doubling of GHGs (2 x CO₂) is projected to cause both gains and losses of agriculture land.
    
·    Each crop has a specific temperature range at which vegetative and reproductive growth will proceed at the optimal rate and exposures to extreme temperatures during these phases can impact growth and yield. Higher temperatures during the reproductive stage of development can affect pollen viability, fertilization and grain or fruit formation. 
    
·    Warming generally allow plants to grow faster that are below their optimum temperature, however for cereal crops faster growth means there is less time for the grain itself to grow and mature, reducing yields. 
    
·    Night-time temperatures are rising faster than daytime temperatures and are expected to continue rise in the future. According to International Rice Research Institute (IRRI), Philippines, the rise of night time temperature decreases rice yield by 10% for each 1°C increase in growing-season night time temperature in the dry season.

Key Facts
    
·    The United Nations Framework Convention on Climate Change (UNFCCC) defines ‘climate change’ as a ‘Change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over the comparable time periods’.
    
·    The main green house gases (GHGs) that have caused the global climate change or global warming are carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O).
    
·    CO₂ is the principal anthropogenic GHG that affects the earth’s radiative balance. It is the reference gas against which other GHGs are measured and therefore has a Global Warming Potential (GWP) of 1. CH₄ and N₂O have a GWP of 21 and 310 respectively.
    
·    CO₂ is responsible for most of the enhanced green house effect of more than 50%, CH₄ for about 10-15% and N₂O for about 8%.
    
·    The global atmospheric concentrations of CO₂, CH₄ and N₂O have increased since 1750. While CO₂ increased from a pre-industrial value of 280 ppm to 379 ppm in 2005, CH₄ increased from 715 ppb to 1774 ppb and N₂O increased from 270 ppb to 319 ppb during the same period.

18.1. INTRODUCTION

Plant genetic resources (PGRs) are the foundation for the development of a food and nutritionally secured society. Food is the foremost important to sustain life and livelihood followed by shelter and cloth. Thus, the slogan of 3Fs may be modified as, “Food, Frame (shelter) and Fibre (cloth)”. All these 3Fs we can get from PGRs. There must be balance between demands and resources. Gradually the demand for basic needs increasing. So, we have to improve the PGRs to cope with the increasing demands. PGRs are the foundation for the development of these 3Fs. India is a country rich in crop biodiversity and genetic resources. The status of Germplasm accessions in the National Gene Bank is being presented in Table 18.1.

17.1. INTRODUCTION

Yam bean is one of the adaptable, low-maintenance, and nutritious food crop grown in moderate soil. It has many synonyms, in India it is known as Mishrikand (Hindi), Keshar or Ram-kaseru or Shankalu (Bengali). The root crops produced by legumes have long recognized as important and the FAO (1979) has recommended them as a source of human nutrition. The tuber is rich in starch (15-20%), 3-4% sugar, and have considerable amount of protein (2-3%). The harvested crop keeps well for months under ambient temperature. Kale (2006) observed relatively high iron contents in storage roots (up to 130 mg/kg of storage root dry matter). It can also be used for alcohol production.

The crop is very hardy, resistant to common insect pests and diseases. Most important is that the crop is not grazed neither by goats nor cows. The crop grows well in hot-humid environment and requires long, warm frost-free growing season. A moist, light textural soil is preferred for production of tuberous roots. As a legume crop, it can be grown without nitrogen fertilizer. Under good growing condition its root nodules habour symbiotic colonies of nitrogen-fixing bacteria- Rhizobium spp. (Nielsen et al., 1998b). A season crop of yam beans can release as much as 53 tons of usable nitrogen per acre into the soil. Mycorrhyzae also associated with the crop, thus facilitating phosphorus uptake. Thus, yam bean is highly suited to the needs of small farmers, and from both an ecological and a socioeconomic perspective

16.1. INTRODUCTION

Millets are a large part of the basic diet for farm households in the world's poorest people in the poorest countries. The production of millets on average for the 5 years have been given in Table 16.1. Top consuming countries are India, Nigeria, Niger and China. However, just because a country is a top global consumer does not mean that millet is a significant source of calories for them. India and China are rank as the 1st and 4th consumers of millet, but due to their population size they rank 11th and 38th in per-capita consumption, accordingly.

Millet particularly the finger millet) is an excellent dietary source of calcium, iron, manganese, and methionine-  an amino acid lacking in the diets of hundred of millions of the poor who live on starchy foods such as cassava, plantain, polished rice, and maize meal. Millet use is diverse, including in cereals (including porridge and kasha), soups, breads and stuffings, fermented beverages, and baby food.

15.1. INTRODUCTION

Finger millet Eleusine indica (L.) is an Old World cereal grass commonly known as ‘finger millet’, is one of the staple food crop especially in India and Africa, which is widely grown in the arid regions of Asia and Africa and important minor millet grown in India.  Eleusine, the generic name, is obtained after the “Eleusine” the Greek Goddess of cereals and the common name finger millet is derived from the finger like branching of the panicle. It is also know by Goosegrass, Yardgrass, Wiregrass, Silver Crabgrass, Crowfoot Grass. It is commonly known as Finger millet in English, Kelvaragu in Tamil, Nachani in Marathi etc. Some Indian varieties of finger millet are Kempu ragi, Ragalli shivalli, Pichakaddi etc.  This crop is one among the hardiest crops which can with stand severe drought conditions and can also grow well under scanty rainfall condition. However with good irrigation facilities the yield of finger millet matches with crops like rice. Finger millet seeds remain free of pests and insects for a long duration extending up to 50 years hence serving as a food reserve in case of tough situations like famine.

14.1. INTRODUCTION

Barley (Hordeum vulgare L. emend. Bowden) is one the most important ancient crops and played very important role in the development of agriculture and human civilization. It has also played crucial role in the progress of science of agriculture, physiology, genetics, plant breeding and malting and brewing science. It is the fourth most cereal crop after rice, wheat and maize in acreages and production in the world.  It is grown and used all around the world in many countries and has fed livestock, poultry and people since ancient time.  Barley was domesticated about 10,000 years ago in the Fertile Crescent of the Near East. Fertile Crescent is considered the first of at least seven primary centres of agriculture origin in the world (Smith, 1998; Baik and Ulrich, 2008). Barley is best known around the world as a feed grain and a premier grains for malting and brewing. When most people think of composition of beer, they only think of barley over other cereals. Although utilization of barley for food is relatively low as compared to other cereals today, throughout its history barley has remained an important and major food source poor people living in Western and Eastern Asia and Northern and Eastern Himalayan region nation like Tibet, Nepal and in Northern and Eastern Africa (Newman and Newman, 2006, 2008). Moreover, there has been resurgence of interest and use of barley as food primarily in the developed world due to an increasing emphasis on incorporating the diversity in consumption of whole grain in people’s diets due to its health benefits.

13.1. INTRODUCTION

Pearl millet crop has a wide adaptability to local environments. It is hardy and can be grown in areas which are very hot and dry and on soils too poor for sorghum. Pearl millet is considered more efficient in utilization of soil moisture and has a higher level of heat tolerance than even sorghum and maize. It is adapted to warm and dry climate but most of the area under the crop is in drought- prone areas of the world. In these areas, pearl millet is usually grown with limited inputs, sparse rainfall, low soil fertility, and also face disease and pest problems, with correspondingly poor yields.
 
The low average yields are primarily a result of the hot, dry conditions where pearl millet is mostly grown, rather than pearl millet plant’s capability. Pearl millet hybrids grown under better conditions yield 3000 to 4000 kg/ha compared to 300 to 800 kg/ha when moisture and soil fertility become limiting factors. A majority of the subsistence farmers who typically cultivate this crop are unable to take advantage of high yield potential because they have limited options for improving their management practices. Pearl millet production can be increased through growing varieties/hybrids with improved tolerance to drought, diseases and responding to higher rates of fertilizer applications.

12.1. INTRODUCTION

Sorghum [Sorghum bicolor (L.) Moench] is an important food/feed/fodder crop in more than 90 countries across the world and it is one of the cheapest sources of energy and micronutrients (Reddy et al., 2009; Ashok Kumar et al., 2011). Considerable efforts have been made to improve sorghum productivity through genetic enhancement and crop production and protection research all over the globe. Sorghum being an often cross-pollinated crop with cross pollination up to 2-15% depending on genotype and environment (House 1985), initially, pure-lines were the target products although phenomenon of heterosis was demonstrated in sorghum as early as in 1927 (Conner and Karper, 1927). Predominant self-pollinating nature of sorghum with tiny florets with single seed per emasculation and pollination prevented commercial exploitation of heterosis for commercial sorghum production. However, the discovery of a stable and heritable cytoplasmic-nuclear male-sterility (CMS) mechanism (Stephens and Holland, 1954), enabling large-scale, economic hybrid seed production gave a fillip to the exploitation of heterosis since early 1960s. The first commercial sorghum hybrid CSH 1 was released in 1964 in India. Using CMS mechanism, large number of commercial hybrids have been developed and released/marketed for commercial cultivation in all sorghum growing regions with strong Indian National Agricultural Research Systems (NARS).

11.1. INTRODUCTION

Sorghum [Sorghum bicolor (L.) Moench] is the fifth most important cereal crop and is the dietary staple of more than 500 million people in over 90 countries, primarily in the developing world. It is grown on 47 m ha in 104 countries in Africa, Asia, Oceania, and the Americas. Among those, USA, Nigeria, India, Mexico, Sudan, China, and Argentina are the major sorghum producers globally. Sorghum grain is mostly used directly for food (55%), and is consumed in the form of porridges (thick or thin) and flat breads; however sorghum is also an important feed grain (33%), especially in Australia and the Americas. Stover (crop residue after grain harvest) is an important fodder source to both milch and draft animals in mixed crop-livestock systems. Sorghum is also a good source of green fodder due to its quick growth and high yield and quality of biomass. Of late, sorghum with sugar-rich juicy stalks (called sweet sorghum) is emerging as an important biofuel crop. Thus sorghum is a unique crop with multiple uses as food, feed, fodder, fuel and fiber. Sorghum is generally grown in rainy season (spring) but in India it is grown in both rainy and postrainy seasons. The postrainy season sorghum grain is prized for its food value (Reddy et al., 2009).

10.1. INTRODUCTION

The development of hybrid breeding methodology in maize and its successful application to exploit heterosis is considered as significant achievement of plant breeding in the present century. 
Even though Beal (1880) suggested for commercial cultivation of F1 varietal hybrids. It was Shull (1909) on the basis of his experiment gave pure line method of corn breeding, which laid foundation for present day hybrid breeding. Pure line methods of maize breeding involve three steps. 
    
·    Large scale inbreeding to obtain many homozygous/nearly homozygous inbred lines. 
    
·    Testing the selected inbred lines in all possible crosses.
    
·    Practical utilization of inbred lines in seed production of single cross hybrids.

9.1. INTRODUCTION

Maize (Zea mays L. ssp. mays 2n = 20), known as corn in some countries is an important cereal crop of the world. The scientific name from Greek word ‘Zea’ for a kind of grain and West Indian word ‘malnis’ for corn. Maize was domesticated in Mesoamerica and hence formed the Mesoamerican people’s identity and later it spread throughout American continent. Maize is widely cultivated throughout the world and a greater weight of maize is produced each year than any other cereal grain. USA produces almost half of the world’s harvest (42.5%) and other top producing countries include China, Brazil, Mexico, Argentina, India and France. During the year 2007, worldwide maize productivity was around 4970 kg per ha. Maize is the only cereal that can be harvested and used at various stages of plant development. The crop can be cultivated on a wide area from 580 N to 400 S from below sea level to altitudes higher than 3000 m and in areas with 250 mm to more than 5000 mm of rainfall per year (Shaw, 1988, Dowswell et al., 1996).

8.1. INTRODUCTION

Exploitation of heterosis through development of hybrid wheat is one of the most attractive options to increase wheat productivity. The efforts on developments of hybrid wheat started in early fifties (Kihara, 1951; Fukasawa, 1953) through cytoplasmic male sterility system (Livers and Heyne, 1968). Later, in seventies, research works from public as well as private sectors have shifted their efforts to the use of gametocide (chemically hybridizing agent-CHA), and a number of gametocides were tested in eighties. In wheat, heterosis is especially interesting for grain yield and for the resistance of plants to both parasites and climate risks (Rousset, 1986). With this advantage in mind, the first phase of hybrid wheat development started in the United States in 1975. Chronological events of wheat hybrid development have been given in Table 8.1. Subsequently, a number of hybrid wheat has been released in countries such as Argentina, France, and United States (Pickett, 1993).

7.1. INTRODUCTION

The cultivation of wheat (Triticum spp.) reaches far back into history. Wheat was one of the first domesticated food crops and for 8000 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.

Wheat is special in several ways. It 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 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.

6.1. INTRODUCTION

After introduction of TN-1 (Taichung Native-1), Jaya, IR8 and other high yielding rice varieties during sixties and seventies, the productivity increased drastically and remained at plateau since last three decades. With no possibility to extend land area for rice cultivation in Asia, there is some scope for production advantages in rice through further expansion of high yielding varieties coverage in Pakistan, Thailand and India, expansion of area under irrigation in Bangladesh, Cambodia, India, Myanmar, the Philippines, Thailand and Vietnam, or expansion of boro rice in Bangladesh, India and Myanmar. Thus, utilization of heterosis has become one of the main methods for increasing yield. Hybrid is one of the viable and proven technologies to improve rice productivity. China is the first successful country to produce hybrid rice in appreciable quantity. This technology not only helped China to increase the rice productivity, but also to save land for crop diversification. The 'National Food Security Mission' has been launched envisaging increase of annual rice production by 10 million tons by 2011-'12. Here, hybrid rice may play important role to achieve the assigned target.