eChapters

13.1 Introduction

Climate change is emerging out to be the greatest challenge to humanity. Climate change may be a change in the mean of the various climatic parameters such as temperature, precipitation, relative humidity, atmospheric gases composition etc. and in properties over a longer period and a larger geographical area. It can also be referred to as any change in climate over time, whether due to natural variability or because of human activity. Climate change is a global challenge threatening sustainability of agriculture and its impact is realized more in the fragile and vulnerable ecosystems. The resource poor small and marginal farmers are more prone to climatic aberrations than other farmers. Predicted population growth over the next 50 years will raise food demand globally higher (Trostle 2008), which is complicated by environmental changes such as climate, biodiversity, water availability, land use, atmospheric and other pollutants, and sea level rise (Misselhorn et al. 2012). Climate change has emerged as a serious global environmental issue having impact on all forms of life. It increases the greenhouse gases like carbon dioxide, nitrous oxide, ozone and methane which may cause impact in terms of increased temperature, more demand for water and increase in biotic and abiotic stresses. It has direct impact on agriculture and horticulture. Due to climate change, low production of horticultural crops is featured. Due to severe cold wave, horticultural crops suffer a yield loss of 10-100% depending upon crop and variety (Hazarika 2013). Mitigation strategies aim to reduce the impact of changes to climate and the associated risks from anthropogenic (human) processes. Adaptive capacity is defined as ‘‘the ability of a system to adjust to climate change (including climate variability and extremes), to moderate potential damages, to take advantage of opportunities, or to cope with the consequences’’ (IPCC 2001, p. 982).

Growth and development of any horticultural crop is mostly depending upon two chief natural factors i.e. climate and soil, which decides success or failure. Therefore, understanding about climate and soil requirements for different horticultural crops for optimum growth and development is a prerequisite for profitable farming.

There is often confusion between weather and climate. Weather describes the condition of the atmosphere over a short period of time e.g. from day to day or week to week. It is current atmospheric conditions including temperature, rainfall, wind, humidity, sky condition at a given place. Climate on the other hand, is the average condition of weather over a longer period of time. Climate is the sum of all the statistical weather information that helps to describe a place or region.

Climate includes different factors namely temperature (minimum & maximum),

Introduction

Climate resilience is the capacity of a system, community, or person to foresee, prepare for, react to, and recover from the consequences of climate change while simultaneously preserving critical functions and minimising long-term harm. This ability is described as the ability to adapt to climate change. In order to handle the issues that are brought about by a changing climate, which include increasing temperatures, severe weather events, rising sea levels, and altering weather patterns, it is necessary to take a proactive approach.

Global warming and climate change are becoming major challenges in the front of global community to deal with. Climate change is no more a myth but it is reality. The IPCC, 5^th assessment report clearly stated that “evidence of climate- change impacts is strongest and most comprehensive for natural systems”. Natural and human systems of almost all continents in the world have been affected by climate change in recent decades (IPCC, 2014). Agriculture is essential for sustainability of human life on earth but change in climate is threatening its sustainability. In recent decades all aspects of food security has been potentially affected by climate change, including food access, utilization, and price stability. It has been projected that in absence of adaptation measure, increases in local temperature by 2°C or more above late-20^th-century levels will negatively impact production of the major crops in tropical and temperate regions.

Agriculture is one of the major economic activities responsible for food security and livelihood for millions of people. Success, production and productivity of agricultural crops are highly dependent on climate, soil and water. Thus climate change will have adverse effect on agricultural crops. High atmospheric temperature, unpredicted erratic rainfall, rapid soil degradation and evolution of new insect and pests due to climate change will offer new challenge to sustain agriculture. Many part of the world and India is already experiencing impact of climate change on agricultural crops (like early maturity, geographical shift and occurrence of new pests) and these impacts are predicted to increase rapidly in future. The increasing concern about adverse impact of climate change on food security has led to extensive research and documentation of impact of climate change on field crops like rice, wheat and maize. While the clear and holistic idea about impact of climate change on horticultural crops like vegetables and fruits are not well documented especially in developing countries like India.

Climate Change: Understanding our Earth and Atmosphere

Our Mother Earth is the fifth largest planet in the solar system and the third from the sun. It is also the sole planet whose name comes from old English language only, and not from names of any other celestial bodies, whose names originated mostly from Greek/Roman mythology. Earth has a diameter of 6378 km, of which the earth crust (uppermost skin) is only 24 km. Earth is the only planet where water exists as liquid and 71% of its surface is covered by water. The earth’s atmosphere is made up mostly of nitrogen (77%) and oxygen (21%) gases. CO₂ consists of a very small (trace) fraction (0.03%) of atmosphere, but is most vital for the life cycle. When earth was created, it has got much higher CO₂ than today, and all of them have been sequestered in rocks as carbonates and dissolved in oceans and a negligible amount is distributed in plant communities. This extremely small quantity of CO₂ is keeping life on earth, by maintaining earth’s temperature at a comfortable 14°C (without CO₂, earth’s temperature would have been -21°C). This effect is called the ‘greenhouse effect’, revolving which all issues of climate change exist. It is also to be noted that water vapour is also an important greenhouse gas (GHG). It is to also to be noted that in spite of substantial increase in solar constant, earth’s average temperature has remained stable for billions of years. It is understood that this was possible through variation in CO₂, and it is the biological processes (Earth biosphere) that controlled the environment over years (Gaia hypothesis).

Climate change presents horticulture with increasing challenges including heat stress, water scarcity, erratic rainfall, extreme weather, new pest pressures, and changing crop suitability. This chapter examines strategies for developing climate-resilient horticultural systems through improved cultivars, efficient irrigation, protected cultivation, mulching, canopy management, soil-health practices, and diversification. Climate-smart production also requires better forecasting, monitoring, risk management, and resource efficiency. Future horticulture is expected to integrate biotechnology, artificial intelligence, precision agriculture, automation, renewable energy, and resilient production systems. The chapter emphasizes adaptation rather than dependence on a single technology, promoting integrated approaches that maintain productivity, quality, profitability, and ecological sustainability under changing climatic conditions.

Climbers

Climbers are group of plants which have weak stems and ability to climb up the support with the help of modified organs for sunlight and air, twiners differ from climber in the way that they do not posses such modified organs but twine around the support cover it and reach the top. Climber are woody or herbaceous plant which climb up the trees and other tall objects with the help of support of their special modified organ, such as tendrils, root, thorns, rootlets, hooks etc.

Tendrils- Bigonia gracilis, Clematis paniculata etc.

Thorns- Bougainvillea species, Climbing roses etc.

Rootlets- Ficus repens etc.

Hooks- Gallium aperine, Rubus australis etc.

Climbers and twiners are important group of plants. Climbers and twiners add the beuty, colour or fragrance in the garden and artificial structure like garden wall, topiary, arches, pergola etc. are made with the help of climbers.

ABSTRACT

Astudy was conducted to establish the regeneration capacity of pseudobulb segments of a Dendrobium hybrid orchid (D. nobile L. x D. chrysotoxum L.) in vitro on full strength (MS) and half strength (½ MS) Murashige and Skoog medium. Pseudobulb segments having 0.3-0.5 cm length cut from the in vitro maintained hybrid orchid were inoculated on both media supplemented with different concentrations and combinations of NAA, BAP and Kn. On MS medium the pseudobulb segments failed to respond, however, in ½ MS medium the explants responded well. Responding explants were maximum (35%) on the medium ½MS + 0.1 mgl^-1 NAA + 0.5 mgl^-1 BAP. An average of two (2) shoot buds per explant were regenerated on ½ MS + 2.0 mgl^-1Kn and ½ MS + 0.1 mgl^-1 NAA + 1.0 mgl^-1 BAP. The regenerated plantlets grew healthily on subculture after separation from the pseudobulb segments.

ABSTRACT

There has been conscious effort to discover and apply biological pesticides for the control of insect predation. Insecticidal proteins/ genes from Bacillus thuringiensis have been deployed as sprays and through transgenic route for crop protection against insect attack and have been successful in protecting the crop damage and environment pollution. However, impending fear of development of resistance to Bt proteins by insects has prompted search for new insecticidal proteins. In this context we are exploring and analysing components of insect immunity as targets for restricting insect feeding behaviour. Insects encounter several microbes during different stages of growth and development. Incidental entry of these microbes elicits a host defense response, which mainly consists of a phenoloxidase (PO) pathway. The invasion of the microbe is recognized by a specific protein, which activates the PO pathway consisting of prophenoloxidase (PPO) & prophenoloxidase activating enzyme (PPAE). Understanding the mechanism of insect immunity will allow us to discover potential targets for inactivating the mechanism of immune action in insects and make them vulnerable to natural microbial infection.

An agronomically important polyphagous pest, Heliothis armigera (Bollworm) was chosen in the present work for studying the components of insect immunity. H. armigera is the most important insect pest of the developing world accounting for heavy damage on various crops including cotton, vegetables, tobacco, potato, groundnut, chickpea and pigeon pea. We have isolated full-length cDNA encoding prophenoloxidase (PPO) and a partial cDNA encoding PPAE from haemocytes of 5th instar larvae of H. armigera. The open reading frame (ORF) of PPO gene is 2.1 kb, which encodes for a 698 amino acid protein with a molecular mass of 77 kDa. Computer-assisted analysis revealed the presence of 60 amino acid long propeptide at the N terminus of protein and 2 copper binding motifs but no signal peptide was detected. The gene was cloned and expressed in a bacterial expression vector pET43b under the induction of IPTG. The SDS-PAGE analysis showed that the protein is expressing in the supernatant in its native form. The expressed enzyme is catalytically active on 4-Methylcatechol upon activation by cetyl pyridinium chloride (CPC). The regulatory role played enzyme in insect immunity is being examined.

ABSTRACT

Production of cardamom in India has been greatly affected by Cardamom mosaic virus (CdMV). The conventional breeding program to develop resistance is a lengthy process. An alternative approach is to develop transgenic cardamom through introduction and expression of viral sequences in the plant. The coat protein (CP) gene of all the CdMV isolates have been cloned in pGEMT vector and sequenced. Sequence comparison studies of the eight isolates of CdMV in their CP and 3’UTR showed that, Kursupara isolate is highly variable from the rest of the isolates (Jacob et al., 2003). Hence the present study was undertaken to introduce the Kursupara CP gene of CdMV into cardamom plants in order to develop pathogen-derived resistance in cardamom. The CP gene of the Kursupara isolate of the virus was amplified with and without the 3’untranslated region (3’UTR) from the viral clone. These PCR products were cloned into the pXcmkn12 vector and sub cloned in to a plant expression vector (pAHC17) at the BamHI site, under maize ubiquitin promoter. Work is in progress towards the biolistic transformation of cardamom with these constructs.

ABSTRACT

The cry1A genes of Bacillus thuringiensis (Bt) are widely used to engineer lepidopteran insect resistance in crop plants including horticultural crops. Continuous exposure of a single kind of Bt toxin can lead to resistance development in insect pest. Due to the difference in structure and unique insecticidal mechanism, cry2A genes are promising candidates for management of resistance development. Since India is rich in biodiversity and genetic resources, indigenous Bt strains are valuable tool for identification of novel cry genes. The present study describes the cloning of cry2Ab from a new indigenous strain of Bt, 14RI. The presence of cry2Ab gene in Bt strain 14RI was confirmed by PCR with primers specific to its internal region. Primers corresponding to the flaking region of cry2Ab were used for amplification of cry2Ab orf from the Bt strain 14RI. The amplified cry2Ab orf was first cloned into the T/A cloning vector, and then fused to the downstream of the cry2Aa promoter along with its orf1 and orf2 in the Bt shuttle vector pHT1301. Acrystalliferous Bt strain 4Q7 has been transformed with recombinant pHT1301 to express the cry2Ab of Bt strain 14RI.

ABSTRACT

The present study was conducted to screen fungal isolates for chitinolytic activity and to clone full-length endochitinase gene from fungus. Among the ten isolates tested (Trichoderma harzianum 1, 2, 3, Trichoderma koningii, Trichoderma virens, Trichoderma viride, Aspergillus oryzae Metarshizium verrucasia, Bauveria bassiana, Nomuraea releyi), Trichoderma koningii showed higest colloidal chitin hydrolysis when screened in Mandels and Reese (1969) salts supplemented with colloidal chitin as the sole carbon source followed by Aspergillus oryzae. Nomuraea releyi showed least chitinolytic activity. Other isolates were on par with each other. The use of diagnostic primers showed specific amplification of 260 bp in Trichoderma harzianum isolates 1,2 and3, Trichoderma koningii and Trichoderma virens, which confirmed presence of endochitinase gene.

Attempts were made to clone full-length endochitinase gene from isolates showing chitinolytic activity. A unique amplicon of 1.7Kb from Trichoderma virens was cloned into linear pTZ57R/T vector with T over hangs. The confirmation of clones was made through blue/white colony assay, plasmid mini-preparation and PCR amplification of these plasmids, sequencing and BLAST search at NCBI. Among the clones confirmed, pSAV804 was sequenced that showed 98% homology with other reported endochitinase genes from Trichoderma spp at DNA and protein level. 85.7% of the protein is conserved. The ORF of the sequence comprises of 822 bases, which deduces 274 amino acids. The position of primer sequence in the insert and BLAST results confirmed the reverse orientation in the vector. The endochitinase gene now needs to clone into the expression and plant expression vectors for further studies.

Clove bean is christened so because of the resemblance of its thickened pedicel to the cloves of spice grown in isolated pockets of Kerala. This crop is neglected so long and remained unexploited though it has good potential for development. The tender and swollen pedicel of the fruit is used as a delicious vegetable vernacularly known as michi in Hindi and Bengali, garyo in Gujarati, kattuthali in Tamil, gariya in Marathi and nithya vazhuthana in Malayalam.

This vegetable grows from sea level as in Western Coasts of Kerala to an altitude of 1700 m amol in the Himalayas (Kirthikar and Basu 1935). The crop grows in the Gangetic plains and in Deccan hills. It is distributed in warmer parts of South and South East Asia including Upper Myanmar, Nepal, Sri Lanka, China and Japan. (Raizada and Saxena 1978).

Stem-borer: Sahyadrassus malabaricus: Hepialidae

Presence of the pest is understood when chewed tissue is seen at at the col­lar region. The mouth of the tunnel in which the borer feeds show pieces of bark, wood and frass particles held together by silk. The saplings break off at the point of injury. When the main stem is attacked, there is mat-like frass at basal region of stem. Larvae girdle main stem and bores downward killing the tree.

Adult moth is peculiar and hangs vertically down by the support of two pairs of legs. Egg period is for 7-10 days, and larvae live for about 10 months inside the larval tunnels. They pupate for 3-5 weeks.

Genus : Syzygium 
Species : aromaticum
Family : Myrtaceae
Chromosome No. : 2n = unknown

Origin and Distribution

The wild species are found growing wild in New Guinea and its cultivation was found on some islands of Moluccas. By the 17th century its cultivation has spread to number of other islands and from Moluccas crop reached Asia. The Britishers further introduced it to in India, Sumatra, Sri Lanka and other countries of south east Asia. Through French, the crop reached Mauritius which further spread to Madagascar, Zanzibar (Africa) and finally reached tropical America (Brazil).

Uses
Chinese valued clove as a spice. In India, regarded as an important spice, dried clove buds or after grinding are used to flavour food, valued for medical purposes (flower and fruit) in south east Asia.

Cluster bean [Cyamopsis tetragonoloba (L.) Taub.] popularly known as guar is a drought hardy, deep-rooted, summer annual legume, grown as feed, fodder, green manure, vegetable and seed in the dry habitats of Rajasthan, Haryana, Gujarat and Punjab and to a limited extent in Uttar Pradesh, Madhya Pradesh and Tamil Nadu. In addition to its major cultivation in India, the crop is grown as a cash crop in different countries like Australia, Brazil and South Africa. The crop is exceptionally known for its higher adaptation towards poor and erratic rains, low inputs and less care. Its other multi uses are soil enrichment in cropping systems, industrial uses, social and dietary uses. These qualities have made it as the most favoured crop of marginal farmers in the arid areas. Being a leguminous annual, its primary use is soil health enrichment through atmospheric nitrogen fixation; on an average basis it is estimated to be  30 kg N ha-1. The young pods of Cluster bean are a source of delicious vegetable from late summer to middle of rainy season. The pods are sweet and can often be cooked as those of Phaseolus bean pods and are a very good source of vitamin A, calcium, iron, phosphorus and ascorbic acid with enriched nutritional value.

Cocoa, Theobroma cacao is an important commercial plantation crop of humid tropics. It was introduced as a mixed crop in India and is cultivated in coconut and arecanut plantations large scale from 1970 onwards. It is grown as an under- storey intercrop with sufficient shade in southern states of India. Tamil Nadu is the major cocoa producing state in India. Some pests of economic importance are described hereunder:

Mealy bugs, Planococcus lilacinus (Ckll.) and P. citri (Pseudococcidae: Hemiptera)

These two species are most prevalent in all cocoa growing tracts of the country. Beside cocoa, it also infests coffee, citrus, guava, mango, etc. The adult female is an oval wingless insect which measures 4mm in length. The body colour is chocolate brown and the dorsal body surface is covered with thick waxy covering (Plate 14g). The male is winged and free living.

Coconut is a traditional plantation crop of India and assumes the status of a high value commercial crop. In India, most of the acreage under coconut palm (90%) lies in the four southern states i.e., Kerala, Tamil Nadu, Karnataka and Andhra Pradesh. Kerala ranks first in area (53.76%) and production (45%) followed by Tamil Nadu, Karnataka and Andhra Pradesh. Coconut is mostly a crop of small farmers in India, the average size of a holding being 0.22 ha. More than 90% of the five million coconut holdings in the country are less than one ha in size. The income derived from such small holdings is not sufficient to sustain even the small families.

1) Bud Rot
Diagnostic Symptoms
• Severe on young palms.
• Yellowish green discoloration of the heart leaf or crown leaf.
• The basal tissues of the leaf rot quickly and can be easily separated from the crown.
• Spindle withers and droop down.
• Older leaves develop irregular, water soaked spots which are sunken in nature.
• The leaves and sheath in the central spindle fall off leaving an outer whorl of green leaves.
• The withered central shoot can be pulled out very easily from the crown.
• The central crown may rot and in few months the tree may wilt.
• Young nuts fail to mature and fall (Fig.1).

Coconut (Cocos nucifera L.) is sacredly considered as Kalpavriksha as it supplements the human beings.The popular name coconut is considered to be derived from Spanish word Coco implying “monkey face” which designates reference to the triple scars embossed on the shell which are identical to two eyes and a nose on the monkey’s face. Coconut belongs to family Arecaceae. Coconut palm has been the platform of a critical and sustainable life support system in the humid tropical parts of India. It is undoubtedly the most utilized plant on planet earth in context of number and wide range of products encompassing from the edible kernel, oil, shell liquid which is used as a refreshing drink, sweet sap and endless derivative of foliage, trunk and fiber utilized for widespread utility in agriculture field.

The production of coconut has continued to expand under the traditional niches of marginal land holders and subsistent farmers in the Southern states of our country. Coconut possesses unique capacity to survive and grow in typically distinct soil conditions while it broadly restricts to the regions possessing medium and high rainfall situations. Coconut plays a pivotal role in the economy of India. India is the leading producer of coconut around the globe possessing 31% share with a production of 20440 million nuts from an area of 1975 thousand hectares. Coconut industry supplements sustenance and livelihood to around 12 million people in India. Coconut is aptly known as Kalpavriksha which sensibly means that each and every part of a coconut is utilizable to support the mankind. The leaves of coconut palms get its utility for thatching of house in traditional ways. Besides this, baskets, sheds and husk are utilized for making coir products. Charcoal and activated carbon are made from shell. Coconut is used daily as a traditional ingredient in local cuisines of various Indian States. The other utility products of coconut include virgin coconut oil, dark chocolate etc. The adoption of these products has generated both income of farmers and employment in coconut sector.