eChapters

INTRODUCTION

Climate change is one of the most important global environmental challenges facing humanity with implications for food production, natural ecosystems, freshwater supply, health, habitat destruction biodiversity, etc. According to the latest scientific assessment, the earth’s climate system has demonstrably changed on both global and regional scales since the pre-industrial era. Since the very beginning of civilization, land resources have been under tremendous pressure for food and forest products. Anthropogenic activities have affected the biosphere through changes in the landuse and forest management activities, thus altering the natural balance of greenhouse gases in the atmosphere. The environmental security thus, has become a serious concern across the globe. The meteorological records have shown significant increase in the environmental temperature referred to as the global warming. Human activities have increased green house gases and raised global temperature by 0.50 C over the past 100 yr, which may increase by 1.4 to 5.8°C during the next century (Bhadwal and Singh 2002). Evidence of this global crisis include the rise in global sea levels by 3.4 mm yr-1 ((http://climate. nasa.gov/vital-signs/sea-level/) through the melting of the world’s snow peaks and glaciers, which poses a threat to millions living in coastal areas. A drastic effect on splitting of huge glacier in the Antarctica has already been registered, which has thrown a challenge to save the earth, lest the very survival of the mankind will be jeopardized. Each degree rise in temperature will displace the limits of tolerance of land species some 125 km towards the poles or 150 m vertically on mountains. The Inter-governmental Panel on Climate Change (IPCC) estimates that 20 to 30 per cent of plants and animals could be at risk of extinction if average global temperatures reach the projected levels (Hawkes et al., 2000).

Greenhouse gas emission is likely to rise by 25-90% by 2030 relative to 2000 and the earth could warm by 3° C at the end of this century. Even with a temperature rise of 1-2.5° C, the Intergovernmental Panel on Climate Change predict serious disastrous effects, including reduction in crop yields in tropical and subtropical areas leading to increased risk of food shortage, spread of climate responsive diseases such as malaria, and an increased risk of extinction of 20-30% of all biodiversity present on earth (IPCC, 2007). Carbon dioxide is the most important among all greenhouse gases. Carbon sequestration may be defined as the process of removing C from the atmosphere and depositing it in a reservoir. It entails the transfer of atmospheric carbon dioxide, and its secure storage in long-lived pools (UNFCCC, 2007).

From the agroforestry point of view, carbon sequestration involves primarily the uptake of atmospheric CO₂ during photosynthesis and transfer of fixed carbon into vegetation and soil pools for ‘secure’ storage. It occurs in two major segments of agroforestry systems; aboveground and belowground. The total amount sequestered in each part differs greatly depending on a number of factors including the region, the type of system, site quality, and previous land-use (Nair, 2012). On average, the soil and aboveground parts are estimated to hold major portions, roughly 60 and 30%, respectively, of the total carbon stored in tree-based land-use systems (Lal, 2010). Sequestering CO₂ from atmosphere through natural techniques such as afforestation, reforestation, natural regeneration of forests and the adaptive agriculture is more economically and ecologically sound in increasing the carbon storage capacity of the terrestrial ecosystems (Dhyani, 2014). Although carbon sequestration through afforestation and reforestation of degraded natural forests has long been considered useful in climate change mitigation, agroforestry offers some distinct advantages (Murthy et al., 2013). The carbon in the aboveground and belowground biomass in an agroforestry system is generally much higher than the equivalent land use without trees. An agroforestry system has higher carbon sequestration potential than pastures or field crops (Kirby and Potvin, 2007).

ABSTRACT

The increasing level of green house gases in general CO₂ in particular has raised concerns about the vulnerability of human, animal and plant life. These concerns have prompted the Governments world over to take the appropriate measures to save them from perspective destruction. Forests though serve as source and sink of the CO₂, there is need to synthesize the impact of climate change on forests and the role of forests in global carbon cycle. Climate change needs to become part of decision making in forest management. Also, the agroforestry, a potential carbon sequestration activity is lagging behind, there is a growing interest in it in countries that have not only ratified Kyoto Protocol but also facing many other ecological problems on their private working land. The Clean Development Mechanism (CDM) offers benefits through sink credits and reduces the negative impact of climate change, therefore, necessary institutional arrangements should be put in place to use CDM projects effectively for generating resources through afforestation and reforestation projects for the well being of present as well as future generation. Forest/agroforestry scientists/managers need to realize the current degree of vulnerability and start thinking about their ability to cope with the impacts. Governments have initiated negotiations on policy actions to reduce the green house gases and addressed the vulnerabilities of the ecological, economic and social systems to climate change. It may be one of the least expensive ways for industries to off-set their carbon emission and tree growers to benefit through the carbon trade. Despite the fact that the certain aspects under Kyoto Protocol are still under clarification and negotiation, the forest plantations will play an important role in carbon sequestration and the implementation of Kyoto Protocol. Since the development of plantation is a slow process, the dividends will only be realized after a gap therefore the new plantation should be taken up without delay and the old one be managed as per their silvicultural rotation.

The young seedling stock and rooted cuttings as well as nursery plants require proper care and nourishment. The operations to be performed regularly in nurseries are as follows.

1. Shifting of plants: The nursery plants grown in the pots or polybags are to be shifted once in 2-3 months to avoid root penetration into the soil. If the taproot penetrates deep into the soil, the chances of mortality increases. Hence shifting of grafts and potted plants has to be done at the said intervals
2. Removal of rootstock sprouts: Once has to keep a constant watch on the sprouts arising on the rootstock, which are to be nipped off as and when, observed, to encourage rapid growth of scion shoots.
3. Irrigation: The young tender seedlings are exacting in their water requirement. Proper and judicious irrigation is an important indicator of a healthy nursery, which solves many problems in the nursery. There are many methods adopted in nurseries. However, it depends upon water availability, kind of nursery plants and its growth stage, etc. These methods are flow or flood irrigation, furrow irrigation, overhead irrigation through rose cans, automizers or sprinkler systems, etc.

Carnation (Dianthus caryophyllus L.) is a member of the family Caryophyllaceae. Dianthus word was first coined by Theophrastus from Greek word “dios” meaning divine and “anthos” meaning flower. It is a half hardy, perennial plant, propagated commercially by terminal cuttings. It is being produced as a cut flower in the world. Carnation cut flower trade contributed about 15% of the world flower market. Till now, new carnation varieties have been produced mainly through conventional breeding method. The breeding procedure typically consists of hybridization, self-pollination and selection (Holly and Baker, 1992). The breeding programme did not get enough momentum due to heterozygosity, limited gene pool and inadequate knowledge of genetic make up. However genetic engineering and molecular breeding have opened the way to achieve novel colour and good vase life of flowers.

ORIGIN AND DISTRIBUTION

It is native of Mediterranean region and its distribution is restricted to Greece, Italy, Sicily and Sardinia (Tutin et al., 1993). According to Pliny, the centre of origin of carnation is Spain. The generic name Dianthus comes from writing of the Theophrastus who lived about 300 BC; dios, divine and anthos, flower; the flower of the gods. The species name caryophyllus is coined from Greek word Caryon, nut and phyllon, leaf. Linnaeus chose the species name, caryophyllus, after the genus of clove, as the fragrance from carnation is reminiscent of clove. The common word carnation probably comes from a Greek word coronation because of its use as decorating the crowns of Greek athletes during ancient times. Carnation has been cultivated for over 2000 years and today commercial cultivation is the result of 200 years of improvement and breeding. During sixteenth century its improvement work was started in various countries. The gardens of Italy, France, Germany, Holland and England have contributed much to the development of cultivars. The natural climates for carnation occur near 30^o N or S latitudes of equator and on the western edges of the continents.

A. Case study: Breeding for disease resistance and yield improvement in Black pepper (Piper nigrum)
Black pepper (Piper nigrum) is one of the most important spice crops globally, often referred to as the “King of Spices.” However, its production is frequently threatened by various diseases, particularly Phytophthora foot rot, which can cause significant yield losses. Over the years, extensive breeding efforts have focused on developing disease-resistant and high-yielding varieties of black pepper.
1. Background
• Primary disease concern: Phytophthora foot rot (caused by Phytophthora capsici) is a major disease affecting black pepper, leading to root and stem rot, defoliation, and ultimately, plant death. Other diseases include slow
decline (caused by nematodes and fungal pathogens) and viral infections.
• Yield challenges: The average yield of black pepper is relatively low, primarily due to the susceptibility of many traditional varieties to diseases and pests, along with poor management practices and climatic challenges.
2. Objectives of breeding programs
• Disease resistance: To develop varieties resistant to Phytophthora foot rot and other significant diseases.
• Yield improvement: To increase the overall productivity of black pepper plants, focusing on higher berry yield, larger berries, and better quality.
• Quality enhancement: To maintain or improve the quality of black pepper in terms of essential oil content, piperine content, and other flavour components.
 

Cashew apple, a highly potential nutritional source, is almost entirely wasted now. In Goa, cashew apple juice is fermented and distilled for production of alcohol. Cashew apple is juicy and swollen. It is a rich reserve of vitamins and minerals. The cashew apple is the peduncle of the nut. Normally the apple is 8 to 10 fold large by weight compared to cashew nut, at ripe stage. Cashew apples can be of different size and shape. The ripe apple is very juicy and fibrous with thin skin. When fully ripe, it gets detached from the pedicel and falls down. In Brazil, cashew is a popular fresh fruit and dwarf types are being evaluated to fulfil the market requirements of fresh cashew apple in terms of red colour, high sugar, low tannin etc.

Global Scenario

Globally, India’s share in the cashew area and production is 20 per cent and 16 per cent, respectively. India occupies the largest area followed by Ivory Coast (19%), Brazil (16%), Indonesia (12%), Vietnam (7%), Nigeria (7%), Benin (5%), Guinea-Bissau (5%), Mozambique (2%) and Philippines (1%). The highest production was from Vietnam (30%) followed by Nigeria (19%), India (16%), Ivory Coast (11%), Brazil (5%), Indonesia (3%), Philippines (3%), Guinea-Bissau (3%), Benin (2%) and Mozambique (2%). Sometimes back, India was credited as largest producer, processor and exporter of cashew in the world but as other cashew producing countries also acquired the know-how of processing and entered in the international market, currently the India’s share in the International market has shrank to 30 per cent only. On the other hand, the domestic consumption in India has increased considerably, owing to largest consumption of cashew kernel. Every year, over 7-8 lakh tonnes of raw cashew nut are imported mainly from African countries and exporting cashew kernel to USA and UK after processing (Saroj, 2013).

Pattern of Growth Flushes in a Bearing Tree

Two or three peak periods of growth are usually observed in a bearing cashew tree, even though under favourable conditions the stray shoot growth may occur almost every month. The pattern of growth of a bearing tree consists of a generative flower flush (reproductive) and a vegetative flush. The vegetative flush, consisting of lateral shoots, always develops soon after the main crop has matured. Flowering is terminal and is universally preceded by the vegetative flush.

There are two types of branching in cashew, intensive and extensive.

Brief History of Cashew Nut Processing Industry in India

As is known in the Cashew Trade Circles, cashewnut was not an indigenous product of India. A few hundred years back, the Portuguese brought it to Goa in India, from Brazil. The Portuguese also took it to their other colonies in Africa viz. Mozambique on the East Coast and Angola on the West Coast. In Mozambique, it spread all over the territory i.e. from Lourenco in the South to Ibo in the North and thence to British East Africa (now Tanzania) and Kenya. Though, now it is known as cashewnut, still in Mozambique and India, it is known by its original Portuguese name ‘CAJU’.

Cashew research in India dates back to 1950’s when Indian Council of Agricultural Research sanctioned ad-hoc schemes in the then composite Madras, Travancore, Cochin and Bombay States. Thus, Kottarakkara (Kerala) in 1952; Ullal (Karnataka in 1953 and Vengurla (Maharashtra) in 1957 came into being as pioneering cashew centres in the country. More research schemes were started with ICAR’s assistance in 1955 at Bapatla (Andhra Pradesh) and in 1956 at Deragaon (now shifted to Kothiali) in Assam. During the period, Central Food Technological Research Institute, Mysore and National Chemical Laboratory, Pune were also engaged in developing technologies for economic utilisation of cashew apple and Cashew Nut Shell Liquid (CNSL). In the second phase of strengthening cashew research in India, the ICAR started All India Spices and Cashewnut Improvement Project in 1971 linking countrywide network among different research centres. Collection, conservation and evaluation of germplasm, hybridization and selection, vegetative propagation, and nutritional studies were the primary areas under this programme.

Maharashtra, the first state was to release cashew variety under the name Vengurla-1 through Dr. Balasaheb Sawant Konkan Krishi Vidyapeeth, Dapoli in the year 1974. So far, 8 varieties have been released from Regional Fruit Research Station, Vengurla (M.S.), of which, Vengurla-4, Vengurla-6, Vengurla-7 and Vengurla-8 are widely accepted for commercial plantation.

• Cashew kernel contains 47% fat, 21% protein and 22% carbohydrates.
• Cashew kernel does not have cholesterol.
• Collection of fallen nuts is known as Gllining.
• India is the largest producer as well exporter of raw cashew nut.
• The USA is the largest importer of cashew nut kernels in the world.
• Cashew is restricted to altitude below 700 m where the temperature does not fall below 20°C for prolong period.
• pH more than 8.0 is not suitable for its commercial cultivation.
• Pruning period: August-September
• Steam method is the most popular method of roasting.
• Best quality whole kernels kernels are obtained from drum roasting.
• Maximum recovery of oil is done using oil bath roasting.
• Inflorescence: Polygamomonocious
• Cashew nut is the III most important agriculture commodity exported from India.
• Broma dryer is a commonly used drier for drying of the kernel.
• The moisture content of the dried kernelranges between 2% to 4%.

Cashew (Anacardium occidentale), is an evergreen tree in the family Anacardiaceae. It is grown for its edible fruits (nuts). Cashew originates from North-East Brazil (Salam and Peter, 2010). As a fast growing woody perennial, is characterized by spreading branches. Cashew trees can reach a height of 12 m and have an economic lifespan of 25 years. A Canopy of cashew develops irregular if not checked properly. In later stage, its canopy shape and size become difficult to manage (Nalini et al., 1999). Manipulation of canopy size and shape by means of pruning and training for its containment and better yield was not felt as a necessary orchard management technique for cashew. Majority of the older plantations are of seedling origin of non-descript material and have poor genetic potentiality. They have become senile. Such plantations can be rejuvenated provided they are managed properly and not very old (Gurupasand et al., 2012). If the plantations are of improved varieties having good genetic make-up such plantations can be rejuvenated by limb pruning or if they are genetically low yielders they need to be top-worked by beheading and grafting with better material for improving the yield performance.

Cattleya belongs to the family Orchidaceae. It is highly important in floriculture and has been cultivated since the 19^th century. The name “Cattleya” was given in the honour of “Sir William Cattley”. Cattleyas have earned the reputation as the “Queen of Orchids” and are known to the public as the ultimate in floral corsages. While no longer the reigning queen of the orchid floral industry it is difficult not to be impressed by a well-flowered Cattleya. No longer limited to white and various shades of lavender and purple, high quality flowers occur in all colours except true blue and black and in a wide range of plant sizes. They are widely known for their large, showy flowers and were used extensively in hybridization for the cut-flower trade until the 1980s when pot plants became more popular.

ORIGIN AND DISTRIBUTION

The genus was named in 1824 by John Lindley after Sir William Cattley who received and was the first to bloom a specimen of Cattleya labiata. William Swainson had discovered the new plant in Pernambuco, Brazil, in 1817 and shipped to the Glasgow Botanic Gardens for identification. After the first importation from Mr. Swainson, no more plants similar to the original Cattleya labiata were discovered for many decades, although many varieties of this species were found. Each variety differed in some way from the plant of Mr. Cattley, either in colour, blooming season or some similar horticultural aspect. Brazil is the centre of distribution, where more than half the species are found (Pabst and Dungs, 1975 and Cruz et al., 2003). They are found naturally only in the western hemisphere, occurring along with Laelias in three major regions of Tropical America i.e. Mexico and Guatemala, northern part of South America from the western Cordilleras of Colombia to British Guiana and the maritime provinces of southern Brazil. Within these three large regions are found most of the species of Cattleya except for C. dowiana in Costa Rica and C. skinneri var. autumnalis from Panama. The plants occur at considerable elevation where the mean temperature is much lower than the mean temperature for the latitude at sea level.

The low productivity of perennial fruits has been attributed to various factors, like small size of holdings, preponderance of old and senile trees and poor management of inputs such as water, nutrients and pesticides. Thickly-shaded mango orchards in Malihabad areas of Uttar Pradesh (Kalloo et al., 2005; Mishra, 2013), lanky as well as sick tall unproductive litchi orchards in Muzaffarpur and its adjoining areas in Bihar (Kumar, 2008), seedling orchards of guava and citrus fruits throughout the country, including disease-affected aonla and other perennial fruit plantations are commonly seen in large tracts in different parts of the country (Pandey et al., 2013; Singh 2007). In pomegranate, the old orchards become non- productive due to incidence of pests and diseases, and negligence (Hiwale, 2009).

The traditional trend of orcharding for most of the tropical and subtropical evergreen perennial fruit trees, in general, are regarded as not responsive to pruning. However, a number of observations made in recent decades have conclusively proved the effectiveness of this important operation in maintaining the sustained fruit yield and keeping the plant well within manageable limits. The efforts have been made to deal perennial fruits in quite details wherever deemed necessary. Climatic factors have been found to affect significantly on fruit bearing as a result of pruning treatments. Though, this aspect is one of the most misconceived and least understood when seen with shoot emergence and shoot physiology for perenation and phase change from vegetative to reproductive. Correct pruning may easily spell the difference between success and failure, yet many growers undertake infinite pains to get the best out of their trees but the neglect to give their consideration to important practice. It is obviously needless to mention here that their such efforts end in futility. For better understanding of principles and practices of pruning, it would be imperative to trace out its historical background. The present level of understanding about pruning has been developed through ages with the increased understanding of growth and developmental processes of fruit plants.

Since historical times, Indian spices have been contributed not only to the country’s wealth and prosperity but also to the subcontinent itself as a whole. Spices precisely witnessed many wars, bloodshed, armoury alongwith the glowing accounts and adventurous voyage by Pliny, Ptolemy, Marco Polo, Vasco da Gamma and other travelers. The Southern parts of India, especially the Malabar Coast, with its abundance of the World’s best pepper, cinnamon and ginger was enormously creating impact of a plethora of spices which attracted the foreign trade and continue even today by creating a unique brand value globally. In the past, invaders travelled to India by overcoming many odds and barriers with the prime focus on capturing spice trade and dominating the trade scenario of those days throughout the world. As a result, gradually Indian spices travelled far and wide to traditional destinations by providing flavor, aroma, pungency, taste and colour to a variety of foods and beverages.

It was the end of 18^th century, from when scientific research began on the idea of origin of cultivated plants. The pioneers of this field were Darwin, Alphonse de Candolle, N.I Vavilov and many more. Charles Darwin wrote his famous book ‘On the Origin of Species by Means of Natural Selection’, or the ‘Preservation of Favoured Races in the Struggle for Life’ published on 24^th November 1859. According to him, cultivated plants may have originated from its wild form after a series of intense modifications. Afterwards, a Swiss botanist Alphonse de Candolle studied 247 cultivated plant species and documented his work in the book “Origin of cultivated plants” in 1886. Later, Vavilov first identified the Centres of origin. He could determine the origin of plants by analyzing the pattern of variation and proposed that, crop plants have been evolved from their wild species in the geographic region of the greatest genetic diversity of that particular plant. That area is known as the primary centres of origin of the particular plant. But, some crop species were found to show substantial genetic diversity even though they did not originate there. Such areas are known as secondary centres of origin for that particular species.

Need for certification

Forest restoration and reforestation experts know the effect the right seed source can have on the long-term economic and ecological success of tree planting efforts. However, unlike stock quality (such as size and health), genetic quality (seed source) cannot be observed by the consumer at the time of stock purchase. Where once the provincial government controlled the source of seed and its destination through the provincial nursery system, seed supply is now in the private sector, and the source is unknown or a matter of trust. Tree planting in general needs help, and the wrong seed source is only one of the many reasons that your planting project may not be successful. Besides, the identity of the source will be tracked throughout the chain of custody until it is presented, as a labeled, certified product to the consumer. The seed source may be from a single parent tree or preferably from a large healthy stand of trees. But if seed is bulked from many locations, the label on the resulting seedlings can only indicate the greater area. For example if a nursery bulked its seed from many counties across a specific place, they can only certify and market that crop as? specific place? not as one from a specific county that may have been a source for the seed. For this reason we will have to encourage collectors and growers to bulk only by tree seed zones to promote certification program for the context of successful tree planting.

India has a wide agroclimatic range i.e. temperate, subtropical and tropical, enabling to achieve horticulture diversification. India is second in fruit and vegetable production at global level. The percentage share of horticulture output in agriculture has become 33%, (Horti statistics, 2018). However, productivity in most of the horticulture commodities is very low below world productivity, as we have not concentrated intensively on some major aspects to achieve competitiveness in horticulture for expansion in international trade.

India has potential to lead the world in horticulture. Horticulture is mostly concerned in different aspects of human beings such as provision of nutritious food to achieve a balanced diet; rural employment, integral part of rainfed and dry land areas, wealth generation through the activities of production, processing, marketing, servicing, and related sectors, economically important in export related activities and associated with all the elements of the supply chain etc. 

A. Biotic and abiotic stresses in spices
1. Black pepper
1a. Challenges of biotic stress in Black pepper breeding
The status and future prospects of breeding for biotic stress resistance in black pepper are essential areas of research due to the significant impact of pests and diseases on black pepper crops. Biotic stress, caused by pathogens, pests, and weeds, can severely affect the yield and quality of black pepper, making the development of resistant varieties a critical objective for breeders.
Current status
1. Research efforts: There have been considerable efforts to identify and develop black pepper varieties that are resistant to various biotic stresses. These include resistance to diseases like Phytophthora foot rot (caused by
Phytophthora capsici), quick wilt, nematode infections, and pest attacks like the pollu beetle.
2. Breeding techniques: Traditional breeding methods have been complemented by molecular breeding techniques. Marker-assisted selection (MAS) is increasingly used to accelerate the development of resistant varieties. The integration of genomic tools has also enhanced the efficiency of identifying resistance genes and their incorporation into high-yielding varieties.
3. Resistance sources: Several resistant genotypes have been identified, but their commercial success is still limited. The genetic diversity within black pepper and related species is explored to find novel resistance genes that can be introduced into cultivated varieties.

Cell walls mainly consist of cellulose, hemicellulose, and lignin in a 4:3:3 ratio. This ratio differs from sources such as hardwood, softwood, and herbs. Besides these three components, natural lignocellulosic materials contain a small amount of pectin, nitrogenous compounds, and the secret ash.

1. Cellulose

2. Hemicellulose

3. Lignin

Cellulose

Cellulose is a glucan polymer consisting of linear chains of 1,4-ß -bonded anhydroglucose units. Cellulose is the structural component of the primary cell wall of the green plants.About 33% of all plant matter is cellulose (the cellulose content of cotton fiber is 90%, that of wood is 40-50% and that of dried hemp is approximately 45%. Cellulose is a straight chain polymer.The number of sugar units in one molecular chain is referred to as the degree of polymerization (DP).Cellulose is insoluble in most solvents including strong alkali. It is difficult to isolate from wood in pure form because it is intimately associated with the lignin and hemicelluloses.